Document And Entity Information
Document And Entity Information | 9 Months Ended |
Sep. 30, 2018shares | |
Entity Registrant Name | ALLIANT ENERGY CORP |
Entity Central Index Key | 352,541 |
Current Fiscal Year End Date | --12-31 |
Entity Filer Category | Large Accelerated Filer |
Entity Common Stock, Shares Outstanding | 235,936,447 |
Document Fiscal Year Focus | 2,018 |
Document Fiscal Period Focus | Q3 |
Document Type | 10-Q |
Amendment Flag | false |
Document Period End Date | Sep. 30, 2018 |
IPL [Member] | |
Entity Registrant Name | INTERSTATE POWER & LIGHT CO |
Entity Central Index Key | 52,485 |
Entity Filer Category | Non-accelerated Filer |
Entity Common Stock, Shares Outstanding | 13,370,788 |
WPL [Member] | |
Entity Registrant Name | WISCONSIN POWER & LIGHT CO |
Entity Central Index Key | 107,832 |
Entity Filer Category | Non-accelerated Filer |
Entity Common Stock, Shares Outstanding | 13,236,601 |
Condensed Consolidated Statemen
Condensed Consolidated Statements Of Income - USD ($) shares in Millions, $ in Millions | 3 Months Ended | 9 Months Ended | ||
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | |
Revenues: | ||||
Electric utility | $ 861.2 | $ 840.6 | $ 2,296.2 | $ 2,199.1 |
Gas utility | 44.8 | 45.8 | 299 | 262.7 |
Other utility | 12.3 | 11.2 | 36.2 | 34.4 |
Non-utility | 10.3 | 9.3 | 29.6 | 29.9 |
Total revenues | 928.6 | 906.9 | 2,661 | 2,526.1 |
Operating expenses: | ||||
Electric production fuel and purchased power | 227.8 | 222.6 | 639.5 | 614.7 |
Electric transmission service | 129.1 | 121 | 375.2 | 363.3 |
Cost of gas sold | 11.3 | 15 | 150 | 135.5 |
Other operation and maintenance | 148.4 | 164.3 | 468.8 | 453.6 |
Depreciation and amortization | 129 | 120.7 | 376.4 | 342.7 |
Taxes other than income taxes | 26.9 | 27 | 78.1 | 79.1 |
Total operating expenses | 672.5 | 670.6 | 2,088 | 1,988.9 |
Operating income | 256.1 | 236.3 | 573 | 537.2 |
Other (income) and deductions: | ||||
Interest expense | 63.3 | 53.9 | 183.8 | 159 |
Equity income from unconsolidated investments, net | (9.8) | (10.1) | (41.6) | (32.9) |
Allowance for funds used during construction | (18.8) | (9.6) | (51.8) | (36.7) |
Other | 1.6 | 4.6 | 6 | 13.1 |
Total other (income) and deductions | 36.3 | 38.8 | 96.4 | 102.5 |
Income from continuing operations before income taxes | 219.8 | 197.5 | 476.6 | 434.7 |
Income tax expense (benefit) | 11.7 | 26.1 | 42.1 | 64.9 |
Income from continuing operations, net of tax | 208.1 | 171.4 | 434.5 | 369.8 |
Income from discontinued operations, net of tax | 0 | 0 | 0 | 1.4 |
Net income | 208.1 | 171.4 | 434.5 | 371.2 |
Preferred dividend requirements of Interstate Power and Light Company | 2.6 | 2.6 | 7.7 | 7.7 |
Net income attributable to common shareowners | $ 205.5 | $ 168.8 | $ 426.8 | $ 363.5 |
Weighted average number of common shares outstanding (basic and diluted) (in shares) | 235.2 | 231 | 232.9 | 229.2 |
Earnings per weighted average common share attributable to Alliant Energy common shareowners (basic and diluted): | ||||
Income from continuing operations, net of tax (basic and diluted) (in dollars per share) | $ 0.87 | $ 0.73 | $ 1.83 | $ 1.58 |
Income from discontinued operations, net of tax (basic and diluted) (in dollars per share) | 0 | 0 | 0 | 0.01 |
Earnings per weighted average common share attributable to Alliant Energy common shareowners (basic and diluted) (in dollars per share) | $ 0.87 | $ 0.73 | $ 1.83 | $ 1.59 |
Amounts attributable to common shareowners: | ||||
Income from continuing operations, net of tax | $ 205.5 | $ 168.8 | $ 426.8 | $ 362.1 |
Income from discontinued operations, net of tax | 0 | 0 | 0 | 1.4 |
Net income attributable to common shareowners | 205.5 | 168.8 | 426.8 | 363.5 |
IPL [Member] | ||||
Revenues: | ||||
Electric utility | 509.2 | 489 | 1,337 | 1,217.6 |
Gas utility | 26.7 | 27.4 | 177 | 147.2 |
Other utility | 11.7 | 11 | 34.2 | 33.3 |
Total revenues | 547.6 | 527.4 | 1,548.2 | 1,398.1 |
Operating expenses: | ||||
Electric production fuel and purchased power | 122.5 | 122.5 | 354 | 330 |
Electric transmission service | 92.8 | 78.2 | 268 | 235 |
Cost of gas sold | 6.4 | 9.9 | 83.8 | 74.6 |
Other operation and maintenance | 94.6 | 102.4 | 297.1 | 283.2 |
Depreciation and amortization | 73.9 | 66.2 | 209.2 | 181 |
Taxes other than income taxes | 14.3 | 14.4 | 39.7 | 41.1 |
Total operating expenses | 404.5 | 393.6 | 1,251.8 | 1,144.9 |
Operating income | 143.1 | 133.8 | 296.4 | 253.2 |
Other (income) and deductions: | ||||
Interest expense | 30.4 | 27.9 | 90.6 | 83.5 |
Allowance for funds used during construction | (11) | (4.7) | (28.3) | (25.1) |
Other | 0.5 | 1.9 | 2 | 5.3 |
Total other (income) and deductions | 19.9 | 25.1 | 64.3 | 63.7 |
Income from continuing operations before income taxes | 123.2 | 108.7 | 232.1 | 189.5 |
Income tax expense (benefit) | (5.9) | (14.3) | (0.5) | (18.6) |
Net income | 129.1 | 123 | 232.6 | 208.1 |
Preferred dividend requirements of Interstate Power and Light Company | 2.6 | 2.6 | 7.7 | 7.7 |
Net income attributable to common shareowners | 126.5 | 120.4 | 224.9 | 200.4 |
Amounts attributable to common shareowners: | ||||
Net income attributable to common shareowners | 126.5 | 120.4 | 224.9 | 200.4 |
WPL [Member] | ||||
Revenues: | ||||
Electric utility | 352 | 351.6 | 959.2 | 981.5 |
Gas utility | 18.1 | 18.4 | 122 | 115.5 |
Other utility | 0.6 | 0.2 | 2 | 1.1 |
Total revenues | 370.7 | 370.2 | 1,083.2 | 1,098.1 |
Operating expenses: | ||||
Electric production fuel and purchased power | 105.3 | 100.1 | 285.5 | 284.7 |
Electric transmission service | 36.3 | 42.8 | 107.2 | 128.3 |
Cost of gas sold | 4.9 | 5.1 | 66.2 | 60.9 |
Other operation and maintenance | 54.2 | 63.3 | 172.8 | 171.8 |
Depreciation and amortization | 54.1 | 53.6 | 164.2 | 158.8 |
Taxes other than income taxes | 11.7 | 11.8 | 35.7 | 35.3 |
Total operating expenses | 266.5 | 276.7 | 831.6 | 839.8 |
Operating income | 104.2 | 93.5 | 251.6 | 258.3 |
Other (income) and deductions: | ||||
Interest expense | 24.2 | 23.1 | 73.5 | 69.1 |
Allowance for funds used during construction | (7.8) | (4.9) | (23.5) | (11.6) |
Other | 1.3 | 2.5 | 3.4 | 7.3 |
Total other (income) and deductions | 17.7 | 20.7 | 53.4 | 64.8 |
Income from continuing operations before income taxes | 86.5 | 72.8 | 198.2 | 193.5 |
Income tax expense (benefit) | 10.2 | 23 | 28.1 | 60.1 |
Net income | 170.1 | 133.4 | ||
Net income attributable to common shareowners | 76.3 | 49.8 | 170.1 | 133.4 |
Amounts attributable to common shareowners: | ||||
Net income attributable to common shareowners | $ 76.3 | $ 49.8 | $ 170.1 | $ 133.4 |
Condensed Consolidated Balance
Condensed Consolidated Balance Sheets - USD ($) $ in Millions | Sep. 30, 2018 | Dec. 31, 2017 |
Current assets: | ||
Cash and cash equivalents | $ 239.7 | $ 27.9 |
Accounts receivable, less allowance for doubtful accounts | 465.3 | 482.8 |
Production fuel, at weighted average cost | 61.3 | 72.3 |
Gas stored underground, at weighted average cost | 43 | 44.5 |
Materials and supplies, at weighted average cost | 106.8 | 105.6 |
Regulatory assets | 82.2 | 84.3 |
Other | 126.5 | 87.7 |
Total current assets | 1,124.8 | 905.1 |
Property, plant and equipment, net | 12,005.2 | 11,234.5 |
Investments: | ||
ATC Holdings | 285.9 | 274.2 |
Other | 138.1 | 121.9 |
Total investments | 424 | 396.1 |
Other assets: | ||
Regulatory assets | 1,612.5 | 1,582.4 |
Deferred charges and other | 103.3 | 69.7 |
Total other assets | 1,715.8 | 1,652.1 |
Total assets | 15,269.8 | 14,187.8 |
Current liabilities: | ||
Current maturities of long-term debt | 506.1 | 855.7 |
Commercial paper | 136.8 | 320.2 |
Other short-term borrowings | 0 | 95 |
Accounts payable | 498.1 | 477.3 |
Regulatory liabilities | 151.7 | 140 |
Other | 255.6 | 260.8 |
Total current liabilities | 1,548.3 | 2,149 |
Long-term debt, net (excluding current portion) | 5,248.2 | 4,010.6 |
Other liabilities: | ||
Deferred tax liabilities | 1,575.2 | 1,478.4 |
Regulatory liabilities | 1,353.9 | 1,357.2 |
Pension and other benefit obligations | 487 | 504 |
Other | 286.8 | 306.4 |
Total other liabilities | 3,702.9 | 3,646 |
Commitments and contingencies (Note 13) | ||
Common equity: | ||
Common stock | 2.4 | 2.3 |
Additional paid-in capital | 2,038.2 | 1,845.5 |
Retained earnings | 2,539.5 | 2,346 |
Accumulated other comprehensive loss | (0.2) | (0.5) |
Shares in deferred compensation trust - 377,723 and 463,365 shares at a weighted average cost of $25.27 and $23.91 per share | (9.5) | (11.1) |
Total common equity | 4,570.4 | 4,182.2 |
Cumulative preferred stock of Interstate Power and Light Company | 200 | 200 |
Total equity | 4,770.4 | 4,382.2 |
Total liabilities and equity | 15,269.8 | 14,187.8 |
IPL [Member] | ||
Current assets: | ||
Cash and cash equivalents | 232.7 | 3.6 |
Accounts receivable, less allowance for doubtful accounts | 277.3 | 264.9 |
Production fuel, at weighted average cost | 42.6 | 52.4 |
Gas stored underground, at weighted average cost | 25.4 | 20.3 |
Materials and supplies, at weighted average cost | 59.3 | 60.6 |
Regulatory assets | 40.3 | 41.9 |
Other | 38 | 32.3 |
Total current assets | 715.6 | 476 |
Property, plant and equipment, net | 6,432.9 | 5,926.2 |
Other assets: | ||
Regulatory assets | 1,209.6 | 1,189.7 |
Deferred charges and other | 20.1 | 14.1 |
Total other assets | 1,229.7 | 1,203.8 |
Total assets | 8,378.2 | 7,606 |
Current liabilities: | ||
Current maturities of long-term debt | 250 | 350 |
Commercial paper | 0 | |
Accounts payable | 279 | 220.3 |
Regulatory liabilities | 95.9 | 69.7 |
Other | 173.8 | 187.7 |
Total current liabilities | 798.7 | 827.7 |
Long-term debt, net (excluding current portion) | 2,551.8 | 2,056 |
Other liabilities: | ||
Deferred tax liabilities | 933 | 910.7 |
Regulatory liabilities | 666.7 | 685.7 |
Pension and other benefit obligations | 168.3 | 173.8 |
Other | 221 | 242.4 |
Total other liabilities | 1,989 | 2,012.6 |
Commitments and contingencies (Note 13) | ||
Common equity: | ||
Common stock | 33.4 | 33.4 |
Additional paid-in capital | 2,027.8 | 1,797.8 |
Retained earnings | 777.5 | 678.5 |
Total common equity | 2,838.7 | 2,509.7 |
Cumulative preferred stock of Interstate Power and Light Company | 200 | 200 |
Total equity | 3,038.7 | 2,709.7 |
Total liabilities and equity | 8,378.2 | 7,606 |
WPL [Member] | ||
Current assets: | ||
Cash and cash equivalents | 6.4 | 23.1 |
Accounts receivable, less allowance for doubtful accounts | 180.6 | 212.2 |
Production fuel, at weighted average cost | 18.7 | 19.9 |
Gas stored underground, at weighted average cost | 17.6 | 24.2 |
Materials and supplies, at weighted average cost | 44.5 | 42.1 |
Regulatory assets | 41.9 | 42.4 |
Prepaid gross receipts tax | 30.7 | 41.3 |
Other | 60.5 | 13.4 |
Total current assets | 400.9 | 418.6 |
Property, plant and equipment, net | 5,183.3 | 4,917.9 |
Other assets: | ||
Regulatory assets | 402.9 | 392.7 |
Deferred charges and other | 57.1 | 27.3 |
Total other assets | 460 | 420 |
Total assets | 6,044.2 | 5,756.5 |
Current liabilities: | ||
Current maturities of long-term debt | 250 | 0 |
Commercial paper | 38.4 | 25 |
Accounts payable | 162.4 | 201.7 |
Regulatory liabilities | 55.8 | 70.3 |
Other | 95.1 | 99.2 |
Total current liabilities | 601.7 | 396.2 |
Long-term debt, net (excluding current portion) | 1,584.5 | 1,833.4 |
Other liabilities: | ||
Deferred tax liabilities | 579.6 | 522.4 |
Regulatory liabilities | 687.2 | 671.5 |
Capital lease obligations - Sheboygan Falls Energy Facility | 62 | 70.2 |
Pension and other benefit obligations | 207 | 213.7 |
Other | 175.6 | 167.6 |
Total other liabilities | 1,711.4 | 1,645.4 |
Commitments and contingencies (Note 13) | ||
Common equity: | ||
Common stock | 66.2 | 66.2 |
Additional paid-in capital | 1,309 | 1,109 |
Retained earnings | 771.4 | 706.3 |
Total common equity | 2,146.6 | 1,881.5 |
Total liabilities and equity | $ 6,044.2 | $ 5,756.5 |
Condensed Consolidated Balanc_2
Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares | Sep. 30, 2018 | Dec. 31, 2017 |
Common stock, par value | $ 0.01 | $ 0.01 |
Common stock, shares authorized (in shares) | 480,000,000 | 480,000,000 |
Common stock, shares outstanding (in shares) | 235,936,447 | 231,348,646 |
Shares in deferred compensation trust (in shares) | 377,723 | 463,365 |
Shares in deferred compensation trust, weighted average cost per share (in dollars per share) | $ 25.27 | $ 23.91 |
IPL [Member] | ||
Common stock, par value | $ 2.50 | $ 2.50 |
Common stock, shares authorized (in shares) | 24,000,000 | 24,000,000 |
Common stock, shares outstanding (in shares) | 13,370,788 | 13,370,788 |
WPL [Member] | ||
Common stock, par value | $ 5 | $ 5 |
Common stock, shares authorized (in shares) | 18,000,000 | 18,000,000 |
Common stock, shares outstanding (in shares) | 13,236,601 | 13,236,601 |
Condensed Consolidated Statem_2
Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended | 9 Months Ended | 12 Months Ended | |||||
Sep. 30, 2018 | Mar. 31, 2018 | Sep. 30, 2017 | Mar. 31, 2017 | Jun. 30, 2018 | Jun. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | Dec. 31, 2017 | |
Cash flows from operating activities: | |||||||||
Net income | $ 208.1 | $ 171.4 | $ 434.5 | $ 371.2 | |||||
Adjustments to reconcile net income to net cash flows from operating activities: | |||||||||
Depreciation and amortization | 376.4 | 342.7 | |||||||
Deferred tax expense and tax credits | 62.5 | 102.7 | |||||||
Equity income from unconsolidated investments, net | (9.8) | (10.1) | (41.6) | (32.9) | |||||
Other | 8.2 | 25.8 | |||||||
Other changes in assets and liabilities: | |||||||||
Accounts receivable | (325.2) | (268.3) | |||||||
Regulatory assets | 27.4 | (108.9) | |||||||
Accounts payable | (47.3) | 3.8 | |||||||
Regulatory liabilities | 14.7 | (64.8) | |||||||
Deferred income taxes | 32.7 | 101 | |||||||
Other | (100.1) | (21) | |||||||
Net cash flows from operating activities | $ 156.3 | $ 173.5 | $ 274.4 | $ 249.8 | 442.2 | 451.3 | |||
Cash flows used for investing activities: | |||||||||
Utility business construction and acquisition expenditures | (1,080.2) | (892.5) | |||||||
Other construction and acquisition expenditures | (47.8) | (156.9) | |||||||
Cash receipts on sold receivables | 337.2 | 432.1 | |||||||
Other | (24.9) | (21.8) | |||||||
Net cash flows used for investing activities | (815.7) | (639.1) | |||||||
Cash flows from financing activities: | |||||||||
Common stock dividends | (233.3) | (215.7) | |||||||
Proceeds from issuance of common stock, net | 191.3 | 143.2 | |||||||
Proceeds from issuance of long-term debt | 1,500 | 0 | |||||||
Payments to retire long-term debt | (603.1) | (2.5) | |||||||
Net change in commercial paper and other short-term borrowings | (278.4) | 281.2 | |||||||
Other | 10.9 | (16.3) | |||||||
Net cash flows from financing activities | 587.4 | 189.9 | |||||||
Net increase (decrease) in cash, cash equivalents and restricted cash | 213.9 | 2.1 | |||||||
Cash, cash equivalents and restricted cash at beginning of period | 33.9 | 13.1 | 33.9 | 13.1 | 33.9 | 13.1 | $ 13.1 | ||
Cash, cash equivalents and restricted cash at end of period | 247.8 | 15.2 | 247.8 | 15.2 | 33.9 | ||||
Supplemental cash flows information: | |||||||||
Interest, net of capitalized interest | (171.6) | (158.5) | |||||||
Income taxes, net | (5) | (11.4) | |||||||
Significant non-cash investing and financing activities: | |||||||||
Accrued capital expenditures | 236.2 | 197.2 | |||||||
Beneficial interest obtained in exchange for securitized accounts receivable | 243.7 | 115.3 | |||||||
IPL [Member] | |||||||||
Cash flows from operating activities: | |||||||||
Net income | 129.1 | 123 | 232.6 | 208.1 | |||||
Adjustments to reconcile net income to net cash flows from operating activities: | |||||||||
Depreciation and amortization | 209.2 | 181 | |||||||
Other | (18.6) | 26.2 | |||||||
Other changes in assets and liabilities: | |||||||||
Accounts receivable | (353.2) | (328.7) | |||||||
Regulatory assets | 14 | (107.8) | |||||||
Accounts payable | (34.5) | 11.6 | |||||||
Regulatory liabilities | 7.5 | (49.6) | |||||||
Deferred income taxes | 22.9 | 88.9 | |||||||
Other | (41) | 8.7 | |||||||
Net cash flows from operating activities | 1.8 | 16.1 | 12.8 | 15.8 | 38.9 | 38.4 | |||
Cash flows used for investing activities: | |||||||||
Utility business construction and acquisition expenditures | (635.2) | (470.1) | |||||||
Cash receipts on sold receivables | 337.2 | 432.1 | |||||||
Other | (30.9) | (21.6) | |||||||
Net cash flows used for investing activities | (328.9) | (59.6) | |||||||
Cash flows from financing activities: | |||||||||
Common stock dividends | (125.9) | (117) | |||||||
Capital contributions from parent | 230 | 100 | |||||||
Proceeds from issuance of long-term debt | 500 | 0 | |||||||
Payments to retire long-term debt | (100) | 0 | |||||||
Net change in commercial paper and other short-term borrowings | 0 | 44 | |||||||
Other | 15 | (2.6) | |||||||
Net cash flows from financing activities | 519.1 | 24.4 | |||||||
Net increase (decrease) in cash, cash equivalents and restricted cash | 229.1 | 3.2 | |||||||
Cash, cash equivalents and restricted cash at beginning of period | 7.2 | 4.2 | 7.2 | 4.2 | 7.2 | 4.2 | 4.2 | ||
Cash, cash equivalents and restricted cash at end of period | 236.3 | 7.4 | 236.3 | 7.4 | 7.2 | ||||
Supplemental cash flows information: | |||||||||
Interest, net of capitalized interest | (89.1) | (84.1) | |||||||
Income taxes, net | (2.4) | 13.2 | |||||||
Significant non-cash investing and financing activities: | |||||||||
Accrued capital expenditures | 142.4 | 71 | |||||||
Beneficial interest obtained in exchange for securitized accounts receivable | 243.7 | 115.3 | |||||||
WPL [Member] | |||||||||
Cash flows from operating activities: | |||||||||
Net income | 170.1 | 133.4 | |||||||
Adjustments to reconcile net income to net cash flows from operating activities: | |||||||||
Depreciation and amortization | 164.2 | 158.8 | |||||||
Deferred tax expense and tax credits | 50.3 | 60.1 | |||||||
Other | (12) | 4.8 | |||||||
Other changes in assets and liabilities: | |||||||||
Accounts receivable | 29.7 | 41.8 | |||||||
Regulatory assets | 13.4 | (1.1) | |||||||
Other | (70.2) | (36.6) | |||||||
Net cash flows from operating activities | 345.5 | 361.2 | |||||||
Cash flows used for investing activities: | |||||||||
Utility business construction and acquisition expenditures | (445) | (454) | |||||||
Other | (23.7) | (18.6) | |||||||
Net cash flows used for investing activities | (468.7) | (472.6) | |||||||
Cash flows from financing activities: | |||||||||
Common stock dividends | (105) | (94.5) | |||||||
Capital contributions from parent | 200 | 40 | |||||||
Net change in commercial paper and other short-term borrowings | 13.4 | 172.3 | |||||||
Other | (1.7) | (9.8) | |||||||
Net cash flows from financing activities | 106.7 | 108 | |||||||
Net increase (decrease) in cash, cash equivalents and restricted cash | (16.5) | (3.4) | |||||||
Cash, cash equivalents and restricted cash at beginning of period | $ 24.2 | $ 6.9 | $ 24.2 | $ 6.9 | 24.2 | 6.9 | 6.9 | ||
Cash, cash equivalents and restricted cash at end of period | $ 7.7 | $ 3.5 | 7.7 | 3.5 | $ 24.2 | ||||
Supplemental cash flows information: | |||||||||
Interest, net of capitalized interest | (68.5) | (68.1) | |||||||
Income taxes, net | (11.2) | (20.2) | |||||||
Significant non-cash investing and financing activities: | |||||||||
Accrued capital expenditures | $ 86.2 | $ 122.3 |
Summary Of Significant Accounti
Summary Of Significant Accounting Policies | 9 Months Ended |
Sep. 30, 2018 | |
Summary Of Significant Accounting Policies | SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES NOTE 1(a) General - The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted, although management believes that the disclosures are adequate to make the information presented not misleading. These Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the latest combined Annual Report on Form 10-K. In the opinion of management, all adjustments, which unless otherwise noted are normal and recurring in nature, necessary for a fair presentation of the results of operations, financial position and cash flows have been made. Results for the nine months ended September 30, 2018 are not necessarily indicative of results that may be expected for the year ending December 31, 2018 . A change in management’s estimates or assumptions could have a material impact on financial condition and results of operations during the period in which such change occurred. Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes, including modifications to the presentation of the components of net periodic benefit costs for defined benefit pension and other postretirement plans in the income statements as discussed in Note 1(d) , restricted cash and cash receipts on sold receivables in the cash flows statements as discussed in Note 1(d) , and segment reporting as discussed in Note 14 . Discontinued operations reported in Alliant Energy’s income statements is related to various warranty claims associated with the sale of RMT, Inc. in 2013, which have resulted in operating expenses and income subsequent to the sale. NOTE 1(b) Cash, Cash Equivalents and Restricted Cash - At September 30, 2018 , Alliant Energy’s and IPL’s cash and cash equivalents included $228 million of money market fund investments with a 2% interest rate. At September 30, 2018 and December 31, 2017 , restricted cash primarily related to deposits with trustees and borrowing requirements in Sheboygan Power, LLC’s debt agreement. Refer to Note 1(d) for discussion of revisions to the cash flows statements to include immaterial restricted cash amounts. NOTE 1(c) Revenue Recognition - Utility - Revenues from Alliant Energy’s utility business are primarily from retail and wholesale electric and gas sales to customers. Utility revenues are recognized over time as services are rendered or commodities are delivered to customers, and include billed and unbilled components. The billed component is based on the reading of customers’ meters, which occurs on a systematic basis throughout each reporting period and represents the fair value of the services provided or commodities delivered. The unbilled component is estimated and recorded at the end of each reporting period based on estimated amounts of energy delivered to customers since the date of each customer’s last meter reading. The unbilled revenue is based on estimates of daily system demand volumes, customer usage by class, temperature impacts, line losses and the most recent customer rates. IPL and WPL accrue revenues from their wholesale customers to the extent that the actual net revenue requirements calculated in accordance with FERC-approved formula rates for the reporting period are higher or lower than the amounts billed to wholesale customers during such period. Regulatory assets or regulatory liabilities are recorded as the offset for these accrued revenues under formulaic rate-making programs. As of September 30, 2018 , the related amounts accrued for IPL and WPL were not material. IPL and WPL participate in bid/offer-based wholesale energy and ancillary services markets operated by MISO. The MISO transactions are grouped together, resulting in a net supply to or net purchase from MISO for each hour of each day. The net supply to MISO is recorded as bulk power sales in “Electric utility revenues” and the net purchase from MISO is recorded in “Electric production fuel and purchased power” in the income statements. Non-utility - Revenues from Alliant Energy’s non-utility businesses are primarily from its Transportation business and are recognized over time as services are rendered or goods are delivered to customers. Taxes Collected from Customers - Sales or various other taxes collected by certain of Alliant Energy’s subsidiaries on behalf of other agencies are recorded on a net basis and are not included in revenues. Other - Alliant Energy, IPL and WPL do not disclose the value of unsatisfied performance obligations for: (i) contracts with an original expected length of one year or less; and (ii) contracts for which revenue is recognized at the amount to which they have the right to invoice for goods delivered or services performed. NOTE 1(d) New Accounting Standards - Revenue Recognition - In May 2014, the Financial Accounting Standards Board issued an accounting standard providing principles for recognizing revenue for the transfer of promised goods or services to customers with the consideration to which the entity expects to be entitled in exchange for those goods or services. Alliant Energy, IPL and WPL adopted this standard on January 1, 2018 using the modified retrospective method of adoption, which was applied to contracts with customers that were completed subsequent to January 1, 2018. Alliant Energy, IPL and WPL utilized a portfolio approach upon adoption, which involved evaluating portfolios of contracts with similar characteristics, where the effects of applying the standard were not expected to be materially different than evaluating on an individual contract basis. Upon adoption, there were no cumulative effect adjustments made to the January 1, 2018 retained earnings balances. In addition, prior period amounts have not been restated to reflect the adoption of this standard and continue to be reported under the accounting standards in effect for those periods. Alliant Energy, IPL and WPL did not have a material change in revenue recognition, including the timing and pattern of revenue recognition, as a result of the adoption of this standard. Refer to Notes 1(c) and 8 for further discussion of revenue recognition. Leases - In February 2016, the Financial Accounting Standards Board issued an accounting standard requiring lease assets and lease liabilities, including operating leases, to be recognized on the balance sheet for all leases with terms longer than 12 months. The standard also requires disclosure of key information about leasing arrangements. Alliant Energy, IPL and WPL will adopt this standard on January 1, 2019 using the modified retrospective method of adoption, which requires cumulative effect adjustments to the balance sheets on January 1, 2019 upon adoption. Prior period amounts will continue to be reported under the accounting standards in effect for those periods. Alliant Energy, IPL and WPL currently plan to elect the land easement transition practical expedient, for which existing land easements that were not previously accounted for as leases under the original accounting standards do not need to be evaluated under the new accounting standard. In addition, Alliant Energy, IPL and WPL evaluated land easements that were previously accounted for as leases and determined that the majority of these land easements relate to joint-use land sites, and do not currently expect them to meet the criteria for leases under the new accounting standard. Therefore, these land easement arrangements will no longer be reflected as operating leases effective January 1, 2019. Alliant Energy, IPL and WPL will continue to evaluate the impact of this standard and do not currently expect a material change to their financial condition or results of operations as a result of adopting the new lease accounting standard. Presentation of Net Periodic Pension and Postretirement Benefit Costs - In March 2017, the Financial Accounting Standards Board issued an accounting standard amending the income statement presentation of the components of net periodic benefit costs for defined benefit pension and other postretirement plans. The standard requires entities to (1) disaggregate the current service cost component from the other components of net periodic benefit costs and present it with other employee compensation costs in the income statement; and (2) include the other components in the income statement outside of operating income. Only the service cost component of net periodic benefit costs is eligible for capitalization into property, plant and equipment; however, IPL and WPL, as rate-regulated entities, capitalize the other components of net periodic benefit costs into regulatory assets or regulatory liabilities. Alliant Energy, IPL and WPL adopted this standard on January 1, 2018 and used the retrospective method of adoption for the presentation requirements and prospective method of adoption for the capitalization requirements. Alliant Energy, IPL and WPL used the actual net periodic benefit costs adjusted for approximately 40% of net periodic benefit costs allocated to capital projects for the retrospective method of adoption for the presentation requirements. The change in presentation resulted in a decrease in “Other operation and maintenance” expenses and an increase in “Other (income) and deductions” in Alliant Energy’s, IPL’s and WPL’s income statements of $4.8 million , $2.0 million and $2.8 million for the three months ended September 30, 2017, and $13.5 million , $5.5 million and $7.9 million for the nine months ended September 30 , 2017, respectively. Cash Flows Statements - In August 2016, the Financial Accounting Standards Board issued an accounting standard providing specific guidance on several cash flow classification matters. The accounting standard requires classification of the consideration received for the beneficial interest obtained for transferring accounts receivable from IPL’s sales of accounts receivable program as an investing activity, instead of an operating activity. Alliant Energy, IPL and WPL retrospectively adopted this standard on January 1, 2018, and use a method of presentation that allocates cash flows between operating and investing activities based on daily transactional activity. For the nine months ended September 30 , 2017, Alliant Energy and IPL reclassified $432.1 million of the related cash received from IPL’s sales of accounts receivable program from operating activities to investing activities based on daily transactional activity. The related impact on Alliant Energy’s and IPL’s cash flows statements for the year ended December 31, 2017 was $461.8 million . For the three months ended March 31, 2018 and the six months ended June 30, 2018, Alliant Energy, IPL and WPL utilized a method of presentation that allocated cash flows between operating and investing activities based on monthly transactional activity. The change in method of presentation to daily transactional activity increases Alliant Energy’s operating cash flows to $156.3 million and $274.4 million , and IPL’s operating cash flows to $1.8 million and $12.8 million , for the three months ended March 31, 2018 and six months ended June 30, 2018, respectively. The change in method of presentation to daily transactional activity increases Alliant Energy’s operating cash flows to $173.5 million and $249.8 million , and IPL’s operating cash flows to $16.1 million and $15.8 million , for the three months ended March 31, 2017 and six months ended June 30, 2017, respectively. In November 2016, the Financial Accounting Standards Board issued an accounting standard requiring restricted cash to be included within beginning-of-period and end-of-period cash and cash equivalents in the cash flows statements. Alliant Energy, IPL and WPL adopted this standard on January 1, 2018, which was applied retrospectively. Refer to Note 1(b) for further discussion of restricted cash. |
IPL [Member] | |
Summary Of Significant Accounting Policies | SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES NOTE 1(a) General - The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted, although management believes that the disclosures are adequate to make the information presented not misleading. These Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the latest combined Annual Report on Form 10-K. In the opinion of management, all adjustments, which unless otherwise noted are normal and recurring in nature, necessary for a fair presentation of the results of operations, financial position and cash flows have been made. Results for the nine months ended September 30, 2018 are not necessarily indicative of results that may be expected for the year ending December 31, 2018 . A change in management’s estimates or assumptions could have a material impact on financial condition and results of operations during the period in which such change occurred. Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes, including modifications to the presentation of the components of net periodic benefit costs for defined benefit pension and other postretirement plans in the income statements as discussed in Note 1(d) , restricted cash and cash receipts on sold receivables in the cash flows statements as discussed in Note 1(d) , and segment reporting as discussed in Note 14 . Discontinued operations reported in Alliant Energy’s income statements is related to various warranty claims associated with the sale of RMT, Inc. in 2013, which have resulted in operating expenses and income subsequent to the sale. NOTE 1(b) Cash, Cash Equivalents and Restricted Cash - At September 30, 2018 , Alliant Energy’s and IPL’s cash and cash equivalents included $228 million of money market fund investments with a 2% interest rate. At September 30, 2018 and December 31, 2017 , restricted cash primarily related to deposits with trustees and borrowing requirements in Sheboygan Power, LLC’s debt agreement. Refer to Note 1(d) for discussion of revisions to the cash flows statements to include immaterial restricted cash amounts. NOTE 1(c) Revenue Recognition - Utility - Revenues from Alliant Energy’s utility business are primarily from retail and wholesale electric and gas sales to customers. Utility revenues are recognized over time as services are rendered or commodities are delivered to customers, and include billed and unbilled components. The billed component is based on the reading of customers’ meters, which occurs on a systematic basis throughout each reporting period and represents the fair value of the services provided or commodities delivered. The unbilled component is estimated and recorded at the end of each reporting period based on estimated amounts of energy delivered to customers since the date of each customer’s last meter reading. The unbilled revenue is based on estimates of daily system demand volumes, customer usage by class, temperature impacts, line losses and the most recent customer rates. IPL and WPL accrue revenues from their wholesale customers to the extent that the actual net revenue requirements calculated in accordance with FERC-approved formula rates for the reporting period are higher or lower than the amounts billed to wholesale customers during such period. Regulatory assets or regulatory liabilities are recorded as the offset for these accrued revenues under formulaic rate-making programs. As of September 30, 2018 , the related amounts accrued for IPL and WPL were not material. IPL and WPL participate in bid/offer-based wholesale energy and ancillary services markets operated by MISO. The MISO transactions are grouped together, resulting in a net supply to or net purchase from MISO for each hour of each day. The net supply to MISO is recorded as bulk power sales in “Electric utility revenues” and the net purchase from MISO is recorded in “Electric production fuel and purchased power” in the income statements. Non-utility - Revenues from Alliant Energy’s non-utility businesses are primarily from its Transportation business and are recognized over time as services are rendered or goods are delivered to customers. Taxes Collected from Customers - Sales or various other taxes collected by certain of Alliant Energy’s subsidiaries on behalf of other agencies are recorded on a net basis and are not included in revenues. Other - Alliant Energy, IPL and WPL do not disclose the value of unsatisfied performance obligations for: (i) contracts with an original expected length of one year or less; and (ii) contracts for which revenue is recognized at the amount to which they have the right to invoice for goods delivered or services performed. NOTE 1(d) New Accounting Standards - Revenue Recognition - In May 2014, the Financial Accounting Standards Board issued an accounting standard providing principles for recognizing revenue for the transfer of promised goods or services to customers with the consideration to which the entity expects to be entitled in exchange for those goods or services. Alliant Energy, IPL and WPL adopted this standard on January 1, 2018 using the modified retrospective method of adoption, which was applied to contracts with customers that were completed subsequent to January 1, 2018. Alliant Energy, IPL and WPL utilized a portfolio approach upon adoption, which involved evaluating portfolios of contracts with similar characteristics, where the effects of applying the standard were not expected to be materially different than evaluating on an individual contract basis. Upon adoption, there were no cumulative effect adjustments made to the January 1, 2018 retained earnings balances. In addition, prior period amounts have not been restated to reflect the adoption of this standard and continue to be reported under the accounting standards in effect for those periods. Alliant Energy, IPL and WPL did not have a material change in revenue recognition, including the timing and pattern of revenue recognition, as a result of the adoption of this standard. Refer to Notes 1(c) and 8 for further discussion of revenue recognition. Leases - In February 2016, the Financial Accounting Standards Board issued an accounting standard requiring lease assets and lease liabilities, including operating leases, to be recognized on the balance sheet for all leases with terms longer than 12 months. The standard also requires disclosure of key information about leasing arrangements. Alliant Energy, IPL and WPL will adopt this standard on January 1, 2019 using the modified retrospective method of adoption, which requires cumulative effect adjustments to the balance sheets on January 1, 2019 upon adoption. Prior period amounts will continue to be reported under the accounting standards in effect for those periods. Alliant Energy, IPL and WPL currently plan to elect the land easement transition practical expedient, for which existing land easements that were not previously accounted for as leases under the original accounting standards do not need to be evaluated under the new accounting standard. In addition, Alliant Energy, IPL and WPL evaluated land easements that were previously accounted for as leases and determined that the majority of these land easements relate to joint-use land sites, and do not currently expect them to meet the criteria for leases under the new accounting standard. Therefore, these land easement arrangements will no longer be reflected as operating leases effective January 1, 2019. Alliant Energy, IPL and WPL will continue to evaluate the impact of this standard and do not currently expect a material change to their financial condition or results of operations as a result of adopting the new lease accounting standard. Presentation of Net Periodic Pension and Postretirement Benefit Costs - In March 2017, the Financial Accounting Standards Board issued an accounting standard amending the income statement presentation of the components of net periodic benefit costs for defined benefit pension and other postretirement plans. The standard requires entities to (1) disaggregate the current service cost component from the other components of net periodic benefit costs and present it with other employee compensation costs in the income statement; and (2) include the other components in the income statement outside of operating income. Only the service cost component of net periodic benefit costs is eligible for capitalization into property, plant and equipment; however, IPL and WPL, as rate-regulated entities, capitalize the other components of net periodic benefit costs into regulatory assets or regulatory liabilities. Alliant Energy, IPL and WPL adopted this standard on January 1, 2018 and used the retrospective method of adoption for the presentation requirements and prospective method of adoption for the capitalization requirements. Alliant Energy, IPL and WPL used the actual net periodic benefit costs adjusted for approximately 40% of net periodic benefit costs allocated to capital projects for the retrospective method of adoption for the presentation requirements. The change in presentation resulted in a decrease in “Other operation and maintenance” expenses and an increase in “Other (income) and deductions” in Alliant Energy’s, IPL’s and WPL’s income statements of $4.8 million , $2.0 million and $2.8 million for the three months ended September 30, 2017, and $13.5 million , $5.5 million and $7.9 million for the nine months ended September 30 , 2017, respectively. Cash Flows Statements - In August 2016, the Financial Accounting Standards Board issued an accounting standard providing specific guidance on several cash flow classification matters. The accounting standard requires classification of the consideration received for the beneficial interest obtained for transferring accounts receivable from IPL’s sales of accounts receivable program as an investing activity, instead of an operating activity. Alliant Energy, IPL and WPL retrospectively adopted this standard on January 1, 2018, and use a method of presentation that allocates cash flows between operating and investing activities based on daily transactional activity. For the nine months ended September 30 , 2017, Alliant Energy and IPL reclassified $432.1 million of the related cash received from IPL’s sales of accounts receivable program from operating activities to investing activities based on daily transactional activity. The related impact on Alliant Energy’s and IPL’s cash flows statements for the year ended December 31, 2017 was $461.8 million . For the three months ended March 31, 2018 and the six months ended June 30, 2018, Alliant Energy, IPL and WPL utilized a method of presentation that allocated cash flows between operating and investing activities based on monthly transactional activity. The change in method of presentation to daily transactional activity increases Alliant Energy’s operating cash flows to $156.3 million and $274.4 million , and IPL’s operating cash flows to $1.8 million and $12.8 million , for the three months ended March 31, 2018 and six months ended June 30, 2018, respectively. The change in method of presentation to daily transactional activity increases Alliant Energy’s operating cash flows to $173.5 million and $249.8 million , and IPL’s operating cash flows to $16.1 million and $15.8 million , for the three months ended March 31, 2017 and six months ended June 30, 2017, respectively. In November 2016, the Financial Accounting Standards Board issued an accounting standard requiring restricted cash to be included within beginning-of-period and end-of-period cash and cash equivalents in the cash flows statements. Alliant Energy, IPL and WPL adopted this standard on January 1, 2018, which was applied retrospectively. Refer to Note 1(b) for further discussion of restricted cash. |
WPL [Member] | |
Summary Of Significant Accounting Policies | SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES NOTE 1(a) General - The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted, although management believes that the disclosures are adequate to make the information presented not misleading. These Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the latest combined Annual Report on Form 10-K. In the opinion of management, all adjustments, which unless otherwise noted are normal and recurring in nature, necessary for a fair presentation of the results of operations, financial position and cash flows have been made. Results for the nine months ended September 30, 2018 are not necessarily indicative of results that may be expected for the year ending December 31, 2018 . A change in management’s estimates or assumptions could have a material impact on financial condition and results of operations during the period in which such change occurred. Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes, including modifications to the presentation of the components of net periodic benefit costs for defined benefit pension and other postretirement plans in the income statements as discussed in Note 1(d) , restricted cash and cash receipts on sold receivables in the cash flows statements as discussed in Note 1(d) , and segment reporting as discussed in Note 14 . Discontinued operations reported in Alliant Energy’s income statements is related to various warranty claims associated with the sale of RMT, Inc. in 2013, which have resulted in operating expenses and income subsequent to the sale. NOTE 1(b) Cash, Cash Equivalents and Restricted Cash - At September 30, 2018 , Alliant Energy’s and IPL’s cash and cash equivalents included $228 million of money market fund investments with a 2% interest rate. At September 30, 2018 and December 31, 2017 , restricted cash primarily related to deposits with trustees and borrowing requirements in Sheboygan Power, LLC’s debt agreement. Refer to Note 1(d) for discussion of revisions to the cash flows statements to include immaterial restricted cash amounts. NOTE 1(c) Revenue Recognition - Utility - Revenues from Alliant Energy’s utility business are primarily from retail and wholesale electric and gas sales to customers. Utility revenues are recognized over time as services are rendered or commodities are delivered to customers, and include billed and unbilled components. The billed component is based on the reading of customers’ meters, which occurs on a systematic basis throughout each reporting period and represents the fair value of the services provided or commodities delivered. The unbilled component is estimated and recorded at the end of each reporting period based on estimated amounts of energy delivered to customers since the date of each customer’s last meter reading. The unbilled revenue is based on estimates of daily system demand volumes, customer usage by class, temperature impacts, line losses and the most recent customer rates. IPL and WPL accrue revenues from their wholesale customers to the extent that the actual net revenue requirements calculated in accordance with FERC-approved formula rates for the reporting period are higher or lower than the amounts billed to wholesale customers during such period. Regulatory assets or regulatory liabilities are recorded as the offset for these accrued revenues under formulaic rate-making programs. As of September 30, 2018 , the related amounts accrued for IPL and WPL were not material. IPL and WPL participate in bid/offer-based wholesale energy and ancillary services markets operated by MISO. The MISO transactions are grouped together, resulting in a net supply to or net purchase from MISO for each hour of each day. The net supply to MISO is recorded as bulk power sales in “Electric utility revenues” and the net purchase from MISO is recorded in “Electric production fuel and purchased power” in the income statements. Non-utility - Revenues from Alliant Energy’s non-utility businesses are primarily from its Transportation business and are recognized over time as services are rendered or goods are delivered to customers. Taxes Collected from Customers - Sales or various other taxes collected by certain of Alliant Energy’s subsidiaries on behalf of other agencies are recorded on a net basis and are not included in revenues. Other - Alliant Energy, IPL and WPL do not disclose the value of unsatisfied performance obligations for: (i) contracts with an original expected length of one year or less; and (ii) contracts for which revenue is recognized at the amount to which they have the right to invoice for goods delivered or services performed. NOTE 1(d) New Accounting Standards - Revenue Recognition - In May 2014, the Financial Accounting Standards Board issued an accounting standard providing principles for recognizing revenue for the transfer of promised goods or services to customers with the consideration to which the entity expects to be entitled in exchange for those goods or services. Alliant Energy, IPL and WPL adopted this standard on January 1, 2018 using the modified retrospective method of adoption, which was applied to contracts with customers that were completed subsequent to January 1, 2018. Alliant Energy, IPL and WPL utilized a portfolio approach upon adoption, which involved evaluating portfolios of contracts with similar characteristics, where the effects of applying the standard were not expected to be materially different than evaluating on an individual contract basis. Upon adoption, there were no cumulative effect adjustments made to the January 1, 2018 retained earnings balances. In addition, prior period amounts have not been restated to reflect the adoption of this standard and continue to be reported under the accounting standards in effect for those periods. Alliant Energy, IPL and WPL did not have a material change in revenue recognition, including the timing and pattern of revenue recognition, as a result of the adoption of this standard. Refer to Notes 1(c) and 8 for further discussion of revenue recognition. Leases - In February 2016, the Financial Accounting Standards Board issued an accounting standard requiring lease assets and lease liabilities, including operating leases, to be recognized on the balance sheet for all leases with terms longer than 12 months. The standard also requires disclosure of key information about leasing arrangements. Alliant Energy, IPL and WPL will adopt this standard on January 1, 2019 using the modified retrospective method of adoption, which requires cumulative effect adjustments to the balance sheets on January 1, 2019 upon adoption. Prior period amounts will continue to be reported under the accounting standards in effect for those periods. Alliant Energy, IPL and WPL currently plan to elect the land easement transition practical expedient, for which existing land easements that were not previously accounted for as leases under the original accounting standards do not need to be evaluated under the new accounting standard. In addition, Alliant Energy, IPL and WPL evaluated land easements that were previously accounted for as leases and determined that the majority of these land easements relate to joint-use land sites, and do not currently expect them to meet the criteria for leases under the new accounting standard. Therefore, these land easement arrangements will no longer be reflected as operating leases effective January 1, 2019. Alliant Energy, IPL and WPL will continue to evaluate the impact of this standard and do not currently expect a material change to their financial condition or results of operations as a result of adopting the new lease accounting standard. Presentation of Net Periodic Pension and Postretirement Benefit Costs - In March 2017, the Financial Accounting Standards Board issued an accounting standard amending the income statement presentation of the components of net periodic benefit costs for defined benefit pension and other postretirement plans. The standard requires entities to (1) disaggregate the current service cost component from the other components of net periodic benefit costs and present it with other employee compensation costs in the income statement; and (2) include the other components in the income statement outside of operating income. Only the service cost component of net periodic benefit costs is eligible for capitalization into property, plant and equipment; however, IPL and WPL, as rate-regulated entities, capitalize the other components of net periodic benefit costs into regulatory assets or regulatory liabilities. Alliant Energy, IPL and WPL adopted this standard on January 1, 2018 and used the retrospective method of adoption for the presentation requirements and prospective method of adoption for the capitalization requirements. Alliant Energy, IPL and WPL used the actual net periodic benefit costs adjusted for approximately 40% of net periodic benefit costs allocated to capital projects for the retrospective method of adoption for the presentation requirements. The change in presentation resulted in a decrease in “Other operation and maintenance” expenses and an increase in “Other (income) and deductions” in Alliant Energy’s, IPL’s and WPL’s income statements of $4.8 million , $2.0 million and $2.8 million for the three months ended September 30, 2017, and $13.5 million , $5.5 million and $7.9 million for the nine months ended September 30 , 2017, respectively. Cash Flows Statements - In August 2016, the Financial Accounting Standards Board issued an accounting standard providing specific guidance on several cash flow classification matters. The accounting standard requires classification of the consideration received for the beneficial interest obtained for transferring accounts receivable from IPL’s sales of accounts receivable program as an investing activity, instead of an operating activity. Alliant Energy, IPL and WPL retrospectively adopted this standard on January 1, 2018, and use a method of presentation that allocates cash flows between operating and investing activities based on daily transactional activity. For the nine months ended September 30 , 2017, Alliant Energy and IPL reclassified $432.1 million of the related cash received from IPL’s sales of accounts receivable program from operating activities to investing activities based on daily transactional activity. The related impact on Alliant Energy’s and IPL’s cash flows statements for the year ended December 31, 2017 was $461.8 million . For the three months ended March 31, 2018 and the six months ended June 30, 2018, Alliant Energy, IPL and WPL utilized a method of presentation that allocated cash flows between operating and investing activities based on monthly transactional activity. The change in method of presentation to daily transactional activity increases Alliant Energy’s operating cash flows to $156.3 million and $274.4 million , and IPL’s operating cash flows to $1.8 million and $12.8 million , for the three months ended March 31, 2018 and six months ended June 30, 2018, respectively. The change in method of presentation to daily transactional activity increases Alliant Energy’s operating cash flows to $173.5 million and $249.8 million , and IPL’s operating cash flows to $16.1 million and $15.8 million , for the three months ended March 31, 2017 and six months ended June 30, 2017, respectively. In November 2016, the Financial Accounting Standards Board issued an accounting standard requiring restricted cash to be included within beginning-of-period and end-of-period cash and cash equivalents in the cash flows statements. Alliant Energy, IPL and WPL adopted this standard on January 1, 2018, which was applied retrospectively. Refer to Note 1(b) for further discussion of restricted cash. |
Regulatory Matters
Regulatory Matters | 9 Months Ended |
Sep. 30, 2018 | |
Public Utilities, General Disclosures [Line Items] | |
Regulatory Matters | REGULATORY MATTERS Regulatory Assets and Regulatory Liabilities - Regulatory assets were comprised of the following items (in millions): Alliant Energy IPL WPL September 30, December 31, September 30, December 31, September 30, December 31, Tax-related $798.3 $778.2 $762.4 $750.5 $35.9 $27.7 Pension and OPEB costs 519.8 548.0 261.2 274.4 258.6 273.6 Asset retirement obligations 111.6 109.3 77.3 72.5 34.3 36.8 EGUs retired early 110.4 63.8 57.2 31.6 53.2 32.2 Derivatives 26.3 45.3 13.3 21.8 13.0 23.5 Emission allowances 24.3 25.5 24.3 25.5 — — Other 104.0 96.6 54.2 55.3 49.8 41.3 $1,694.7 $1,666.7 $1,249.9 $1,231.6 $444.8 $435.1 Regulatory liabilities were comprised of the following items (in millions): Alliant Energy IPL WPL September 30, December 31, September 30, December 31, September 30, December 31, Tax-related $891.1 $899.4 $389.9 $399.5 $501.2 $499.9 Cost of removal obligations 401.0 410.0 274.0 274.5 127.0 135.5 Electric transmission cost recovery 97.0 90.4 37.9 26.4 59.1 64.0 Commodity cost recovery 20.1 21.0 13.6 14.6 6.5 6.4 IPL’s tax benefit riders 13.0 25.0 13.0 25.0 — — Other 83.4 51.4 34.2 15.4 49.2 36.0 $1,505.6 $1,497.2 $762.6 $755.4 $743.0 $741.8 Tax-related - During the nine months ended September 30 , 2018 , Alliant Energy’s and IPL’s tax-related regulatory assets increased primarily due to property-related differences for qualifying repairs expenditures. Alliant Energy’s and IPL’s tax-related regulatory assets are generally impacted by certain property-related differences at IPL for which deferred tax is not recorded in the income statement pursuant to Iowa rate-making principles. Deferred tax amounts for such property-related differences at IPL are recorded to regulatory assets, along with the necessary revenue requirement tax gross-ups. Partially offsetting the increase to tax-related regulatory assets from property-related differences discussed above was a decrease due to the impacts of Iowa tax reform. In May 2018, Iowa tax reform was enacted, resulting in a reduction in the Iowa income tax rate from 12% to 9.8% , effective January 1, 2021 and the elimination of the deduction for federal income taxes, effective January 1, 2022. Alliant Energy’s and IPL’s deferred tax assets and liabilities as of June 30, 2018 were remeasured based upon the new tax rate. Alliant Energy and IPL recorded the net changes from remeasuring deferred tax assets and liabilities as a change in regulatory assets or regulatory liabilities. During the nine months ended September 30 , 2018 , as a result of Iowa tax reform, Alliant Energy’s and IPL’s tax-related regulatory assets decreased $33.7 million and tax-related regulatory liabilities increased $7.3 million . Electric generating units retired early - In June 2018, IPL retired the natural gas-fired M.L. Kapp Generating Station and reclassified the remaining net book value of this EGU from property, plant and equipment to a regulatory asset on Alliant Energy’s and IPL’s balance sheets. The remaining net book value, which was $29 million as of September 30, 2018 , is currently included in IPL’s rate base and IPL is earning a return of and a return on the outstanding balance. IPL expects continued recovery of the remaining net book value to be addressed in a future rate review. In September 2018, WPL retired the coal-fired Edgewater Unit 4 and reclassified the remaining net book value of this EGU from property, plant and equipment to a regulatory asset on Alliant Energy’s and WPL’s balance sheets. The remaining net book value, which was $24 million as of September 30, 2018 , is currently included in WPL’s rate base and WPL is earning a return of and a return on the outstanding balance. WPL will continue to recover the remaining net book value of this EGU from both its retail and wholesale customers over a 10 -year period beginning January 1, 2019 pursuant to PSCW and FERC orders. Other - In January 2018, the IUB issued an order requiring IPL and other investor-owned utilities in Iowa to track all calculated differences since January 1, 2018 resulting from Federal Tax Reform, such that any over-collections can be refunded to its customers at a future date. Pursuant to IUB approval, the retail electric portion of IPL’s Federal Tax Reform benefits is currently being refunded to customers, beginning May 2018. In January 2018, the PSCW issued an order directing WPL and other investor-owned utilities in Wisconsin to defer the revenue requirement impacts resulting from Federal Tax Reform since its inception. Pursuant to PSCW approval, the retail electric and gas portions of WPL’s Federal Tax Reform benefits are currently being refunded to customers, beginning June 2018. Alliant Energy, IPL, and WPL refunded Federal Tax Reform benefits of $20 million , $9 million and $11 million for the three months ended September 30, 2018, and $47 million , $16 million and $31 million for the nine months ended September 30, 2018, respectively, which were recorded as a reduction in revenues. As of September 30, 2018 , Alliant Energy’s, IPL’s and WPL’s remaining deferrals related to Federal Tax Reform were $22 million , $19 million and $3 million , respectively, which are included in “Other” in the regulatory liabilities table above. In December 2016, WPL received an order from the PSCW related to its retail electric and gas rate review for the 2017/2018 Test Period. The order included provisions that require WPL to defer a portion of its earnings if its annual regulatory return on common equity exceeds certain levels in 2018. As of September 30, 2018 , Alliant Energy and WPL deferred $12 million of WPL’s 2018 earnings related to this provision, which is included in “Other” in the regulatory liabilities table above. Utility Rate Reviews - IPL’s Retail Gas Rate Review (2017 Test Year) - In May 2018, IPL filed a request with the IUB to increase annual gas base rates for its Iowa retail gas customers by $20 million , or approximately 8% . The request was based on a 2017 historical Test Year as adjusted for certain known and measurable changes occurring up to 12 months after the commencement of the proceeding. The key drivers for the filing included recovery of capital projects, partially offset by the benefits of Federal Tax Reform. An interim retail gas rate increase of $11 million , or approximately 5% , on an annual basis, was implemented effective May 14, 2018. The interim rate increase does not require regulatory approval; however, it will be subject to refund pending determination of final rates. In September 2018, IPL and parties to the proceeding filed a unanimous settlement agreement with the IUB, proposing an annual retail gas base rate increase of $14 million , or approximately 6% . IPL currently expects a final decision from the IUB in 2018 with final rates effective by late 2018 or the first quarter of 2019. The IUB must issue a decision on requests for retail rate changes within 10 months from the date the application is filed. IPL’s Retail Electric Rate Review (2016 Test Year) - In April 2017, IPL filed a request with the IUB to increase annual electric base rates for its Iowa retail electric customers. An interim retail electric base rate increase of $102 million , or approximately 7% , on an annual basis, was implemented effective April 13, 2017. In September 2017, IPL reached a settlement agreement with intervener groups for an annual electric base rate increase of $130 million , or approximately 9% . In February 2018, the IUB issued an order approving the settlement. Final rates were effective May 1, 2018. WPL’s Retail Electric and Gas Rate Review (2019/2020 Test Period) - In September 2018, the PSCW issued an order approving WPL’s proposed settlement for its retail electric and gas rate review covering the 2019/2020 Test Period, which was based on a stipulated agreement between WPL and intervener groups. Under the settlement, WPL retail electric and gas base rates will not change from current levels through the end of 2020. |
IPL [Member] | |
Public Utilities, General Disclosures [Line Items] | |
Regulatory Matters | REGULATORY MATTERS Regulatory Assets and Regulatory Liabilities - Regulatory assets were comprised of the following items (in millions): Alliant Energy IPL WPL September 30, December 31, September 30, December 31, September 30, December 31, Tax-related $798.3 $778.2 $762.4 $750.5 $35.9 $27.7 Pension and OPEB costs 519.8 548.0 261.2 274.4 258.6 273.6 Asset retirement obligations 111.6 109.3 77.3 72.5 34.3 36.8 EGUs retired early 110.4 63.8 57.2 31.6 53.2 32.2 Derivatives 26.3 45.3 13.3 21.8 13.0 23.5 Emission allowances 24.3 25.5 24.3 25.5 — — Other 104.0 96.6 54.2 55.3 49.8 41.3 $1,694.7 $1,666.7 $1,249.9 $1,231.6 $444.8 $435.1 Regulatory liabilities were comprised of the following items (in millions): Alliant Energy IPL WPL September 30, December 31, September 30, December 31, September 30, December 31, Tax-related $891.1 $899.4 $389.9 $399.5 $501.2 $499.9 Cost of removal obligations 401.0 410.0 274.0 274.5 127.0 135.5 Electric transmission cost recovery 97.0 90.4 37.9 26.4 59.1 64.0 Commodity cost recovery 20.1 21.0 13.6 14.6 6.5 6.4 IPL’s tax benefit riders 13.0 25.0 13.0 25.0 — — Other 83.4 51.4 34.2 15.4 49.2 36.0 $1,505.6 $1,497.2 $762.6 $755.4 $743.0 $741.8 Tax-related - During the nine months ended September 30 , 2018 , Alliant Energy’s and IPL’s tax-related regulatory assets increased primarily due to property-related differences for qualifying repairs expenditures. Alliant Energy’s and IPL’s tax-related regulatory assets are generally impacted by certain property-related differences at IPL for which deferred tax is not recorded in the income statement pursuant to Iowa rate-making principles. Deferred tax amounts for such property-related differences at IPL are recorded to regulatory assets, along with the necessary revenue requirement tax gross-ups. Partially offsetting the increase to tax-related regulatory assets from property-related differences discussed above was a decrease due to the impacts of Iowa tax reform. In May 2018, Iowa tax reform was enacted, resulting in a reduction in the Iowa income tax rate from 12% to 9.8% , effective January 1, 2021 and the elimination of the deduction for federal income taxes, effective January 1, 2022. Alliant Energy’s and IPL’s deferred tax assets and liabilities as of June 30, 2018 were remeasured based upon the new tax rate. Alliant Energy and IPL recorded the net changes from remeasuring deferred tax assets and liabilities as a change in regulatory assets or regulatory liabilities. During the nine months ended September 30 , 2018 , as a result of Iowa tax reform, Alliant Energy’s and IPL’s tax-related regulatory assets decreased $33.7 million and tax-related regulatory liabilities increased $7.3 million . Electric generating units retired early - In June 2018, IPL retired the natural gas-fired M.L. Kapp Generating Station and reclassified the remaining net book value of this EGU from property, plant and equipment to a regulatory asset on Alliant Energy’s and IPL’s balance sheets. The remaining net book value, which was $29 million as of September 30, 2018 , is currently included in IPL’s rate base and IPL is earning a return of and a return on the outstanding balance. IPL expects continued recovery of the remaining net book value to be addressed in a future rate review. In September 2018, WPL retired the coal-fired Edgewater Unit 4 and reclassified the remaining net book value of this EGU from property, plant and equipment to a regulatory asset on Alliant Energy’s and WPL’s balance sheets. The remaining net book value, which was $24 million as of September 30, 2018 , is currently included in WPL’s rate base and WPL is earning a return of and a return on the outstanding balance. WPL will continue to recover the remaining net book value of this EGU from both its retail and wholesale customers over a 10 -year period beginning January 1, 2019 pursuant to PSCW and FERC orders. Other - In January 2018, the IUB issued an order requiring IPL and other investor-owned utilities in Iowa to track all calculated differences since January 1, 2018 resulting from Federal Tax Reform, such that any over-collections can be refunded to its customers at a future date. Pursuant to IUB approval, the retail electric portion of IPL’s Federal Tax Reform benefits is currently being refunded to customers, beginning May 2018. In January 2018, the PSCW issued an order directing WPL and other investor-owned utilities in Wisconsin to defer the revenue requirement impacts resulting from Federal Tax Reform since its inception. Pursuant to PSCW approval, the retail electric and gas portions of WPL’s Federal Tax Reform benefits are currently being refunded to customers, beginning June 2018. Alliant Energy, IPL, and WPL refunded Federal Tax Reform benefits of $20 million , $9 million and $11 million for the three months ended September 30, 2018, and $47 million , $16 million and $31 million for the nine months ended September 30, 2018, respectively, which were recorded as a reduction in revenues. As of September 30, 2018 , Alliant Energy’s, IPL’s and WPL’s remaining deferrals related to Federal Tax Reform were $22 million , $19 million and $3 million , respectively, which are included in “Other” in the regulatory liabilities table above. In December 2016, WPL received an order from the PSCW related to its retail electric and gas rate review for the 2017/2018 Test Period. The order included provisions that require WPL to defer a portion of its earnings if its annual regulatory return on common equity exceeds certain levels in 2018. As of September 30, 2018 , Alliant Energy and WPL deferred $12 million of WPL’s 2018 earnings related to this provision, which is included in “Other” in the regulatory liabilities table above. Utility Rate Reviews - IPL’s Retail Gas Rate Review (2017 Test Year) - In May 2018, IPL filed a request with the IUB to increase annual gas base rates for its Iowa retail gas customers by $20 million , or approximately 8% . The request was based on a 2017 historical Test Year as adjusted for certain known and measurable changes occurring up to 12 months after the commencement of the proceeding. The key drivers for the filing included recovery of capital projects, partially offset by the benefits of Federal Tax Reform. An interim retail gas rate increase of $11 million , or approximately 5% , on an annual basis, was implemented effective May 14, 2018. The interim rate increase does not require regulatory approval; however, it will be subject to refund pending determination of final rates. In September 2018, IPL and parties to the proceeding filed a unanimous settlement agreement with the IUB, proposing an annual retail gas base rate increase of $14 million , or approximately 6% . IPL currently expects a final decision from the IUB in 2018 with final rates effective by late 2018 or the first quarter of 2019. The IUB must issue a decision on requests for retail rate changes within 10 months from the date the application is filed. IPL’s Retail Electric Rate Review (2016 Test Year) - In April 2017, IPL filed a request with the IUB to increase annual electric base rates for its Iowa retail electric customers. An interim retail electric base rate increase of $102 million , or approximately 7% , on an annual basis, was implemented effective April 13, 2017. In September 2017, IPL reached a settlement agreement with intervener groups for an annual electric base rate increase of $130 million , or approximately 9% . In February 2018, the IUB issued an order approving the settlement. Final rates were effective May 1, 2018. WPL’s Retail Electric and Gas Rate Review (2019/2020 Test Period) - In September 2018, the PSCW issued an order approving WPL’s proposed settlement for its retail electric and gas rate review covering the 2019/2020 Test Period, which was based on a stipulated agreement between WPL and intervener groups. Under the settlement, WPL retail electric and gas base rates will not change from current levels through the end of 2020. |
WPL [Member] | |
Public Utilities, General Disclosures [Line Items] | |
Regulatory Matters | REGULATORY MATTERS Regulatory Assets and Regulatory Liabilities - Regulatory assets were comprised of the following items (in millions): Alliant Energy IPL WPL September 30, December 31, September 30, December 31, September 30, December 31, Tax-related $798.3 $778.2 $762.4 $750.5 $35.9 $27.7 Pension and OPEB costs 519.8 548.0 261.2 274.4 258.6 273.6 Asset retirement obligations 111.6 109.3 77.3 72.5 34.3 36.8 EGUs retired early 110.4 63.8 57.2 31.6 53.2 32.2 Derivatives 26.3 45.3 13.3 21.8 13.0 23.5 Emission allowances 24.3 25.5 24.3 25.5 — — Other 104.0 96.6 54.2 55.3 49.8 41.3 $1,694.7 $1,666.7 $1,249.9 $1,231.6 $444.8 $435.1 Regulatory liabilities were comprised of the following items (in millions): Alliant Energy IPL WPL September 30, December 31, September 30, December 31, September 30, December 31, Tax-related $891.1 $899.4 $389.9 $399.5 $501.2 $499.9 Cost of removal obligations 401.0 410.0 274.0 274.5 127.0 135.5 Electric transmission cost recovery 97.0 90.4 37.9 26.4 59.1 64.0 Commodity cost recovery 20.1 21.0 13.6 14.6 6.5 6.4 IPL’s tax benefit riders 13.0 25.0 13.0 25.0 — — Other 83.4 51.4 34.2 15.4 49.2 36.0 $1,505.6 $1,497.2 $762.6 $755.4 $743.0 $741.8 Tax-related - During the nine months ended September 30 , 2018 , Alliant Energy’s and IPL’s tax-related regulatory assets increased primarily due to property-related differences for qualifying repairs expenditures. Alliant Energy’s and IPL’s tax-related regulatory assets are generally impacted by certain property-related differences at IPL for which deferred tax is not recorded in the income statement pursuant to Iowa rate-making principles. Deferred tax amounts for such property-related differences at IPL are recorded to regulatory assets, along with the necessary revenue requirement tax gross-ups. Partially offsetting the increase to tax-related regulatory assets from property-related differences discussed above was a decrease due to the impacts of Iowa tax reform. In May 2018, Iowa tax reform was enacted, resulting in a reduction in the Iowa income tax rate from 12% to 9.8% , effective January 1, 2021 and the elimination of the deduction for federal income taxes, effective January 1, 2022. Alliant Energy’s and IPL’s deferred tax assets and liabilities as of June 30, 2018 were remeasured based upon the new tax rate. Alliant Energy and IPL recorded the net changes from remeasuring deferred tax assets and liabilities as a change in regulatory assets or regulatory liabilities. During the nine months ended September 30 , 2018 , as a result of Iowa tax reform, Alliant Energy’s and IPL’s tax-related regulatory assets decreased $33.7 million and tax-related regulatory liabilities increased $7.3 million . Electric generating units retired early - In June 2018, IPL retired the natural gas-fired M.L. Kapp Generating Station and reclassified the remaining net book value of this EGU from property, plant and equipment to a regulatory asset on Alliant Energy’s and IPL’s balance sheets. The remaining net book value, which was $29 million as of September 30, 2018 , is currently included in IPL’s rate base and IPL is earning a return of and a return on the outstanding balance. IPL expects continued recovery of the remaining net book value to be addressed in a future rate review. In September 2018, WPL retired the coal-fired Edgewater Unit 4 and reclassified the remaining net book value of this EGU from property, plant and equipment to a regulatory asset on Alliant Energy’s and WPL’s balance sheets. The remaining net book value, which was $24 million as of September 30, 2018 , is currently included in WPL’s rate base and WPL is earning a return of and a return on the outstanding balance. WPL will continue to recover the remaining net book value of this EGU from both its retail and wholesale customers over a 10 -year period beginning January 1, 2019 pursuant to PSCW and FERC orders. Other - In January 2018, the IUB issued an order requiring IPL and other investor-owned utilities in Iowa to track all calculated differences since January 1, 2018 resulting from Federal Tax Reform, such that any over-collections can be refunded to its customers at a future date. Pursuant to IUB approval, the retail electric portion of IPL’s Federal Tax Reform benefits is currently being refunded to customers, beginning May 2018. In January 2018, the PSCW issued an order directing WPL and other investor-owned utilities in Wisconsin to defer the revenue requirement impacts resulting from Federal Tax Reform since its inception. Pursuant to PSCW approval, the retail electric and gas portions of WPL’s Federal Tax Reform benefits are currently being refunded to customers, beginning June 2018. Alliant Energy, IPL, and WPL refunded Federal Tax Reform benefits of $20 million , $9 million and $11 million for the three months ended September 30, 2018, and $47 million , $16 million and $31 million for the nine months ended September 30, 2018, respectively, which were recorded as a reduction in revenues. As of September 30, 2018 , Alliant Energy’s, IPL’s and WPL’s remaining deferrals related to Federal Tax Reform were $22 million , $19 million and $3 million , respectively, which are included in “Other” in the regulatory liabilities table above. In December 2016, WPL received an order from the PSCW related to its retail electric and gas rate review for the 2017/2018 Test Period. The order included provisions that require WPL to defer a portion of its earnings if its annual regulatory return on common equity exceeds certain levels in 2018. As of September 30, 2018 , Alliant Energy and WPL deferred $12 million of WPL’s 2018 earnings related to this provision, which is included in “Other” in the regulatory liabilities table above. Utility Rate Reviews - IPL’s Retail Gas Rate Review (2017 Test Year) - In May 2018, IPL filed a request with the IUB to increase annual gas base rates for its Iowa retail gas customers by $20 million , or approximately 8% . The request was based on a 2017 historical Test Year as adjusted for certain known and measurable changes occurring up to 12 months after the commencement of the proceeding. The key drivers for the filing included recovery of capital projects, partially offset by the benefits of Federal Tax Reform. An interim retail gas rate increase of $11 million , or approximately 5% , on an annual basis, was implemented effective May 14, 2018. The interim rate increase does not require regulatory approval; however, it will be subject to refund pending determination of final rates. In September 2018, IPL and parties to the proceeding filed a unanimous settlement agreement with the IUB, proposing an annual retail gas base rate increase of $14 million , or approximately 6% . IPL currently expects a final decision from the IUB in 2018 with final rates effective by late 2018 or the first quarter of 2019. The IUB must issue a decision on requests for retail rate changes within 10 months from the date the application is filed. IPL’s Retail Electric Rate Review (2016 Test Year) - In April 2017, IPL filed a request with the IUB to increase annual electric base rates for its Iowa retail electric customers. An interim retail electric base rate increase of $102 million , or approximately 7% , on an annual basis, was implemented effective April 13, 2017. In September 2017, IPL reached a settlement agreement with intervener groups for an annual electric base rate increase of $130 million , or approximately 9% . In February 2018, the IUB issued an order approving the settlement. Final rates were effective May 1, 2018. WPL’s Retail Electric and Gas Rate Review (2019/2020 Test Period) - In September 2018, the PSCW issued an order approving WPL’s proposed settlement for its retail electric and gas rate review covering the 2019/2020 Test Period, which was based on a stipulated agreement between WPL and intervener groups. Under the settlement, WPL retail electric and gas base rates will not change from current levels through the end of 2020. |
Property, Plant and Equipment
Property, Plant and Equipment | 9 Months Ended |
Sep. 30, 2018 | |
Property, Plant and Equipment [Line Items] | |
Property, Plant and Equipment | PROPERTY, PLANT AND EQUIPMENT Utility - Natural Gas-Fired Generation Project - WPL’s West Riverside Energy Center - WPL is currently constructing West Riverside, an approximate 730 MW natural gas-fired combined-cycle EGU. Construction began in 2016 and is currently expected to be completed by the end of 2019. As of September 30, 2018 , Alliant Energy and WPL recorded capitalized expenditures of $438 million and AFUDC of $35 million for West Riverside in “Property, plant and equipment, net” on their balance sheets. These capital expenditures reflect WPL’s portion of West Riverside. Certain electric cooperatives, which currently have wholesale power supply agreements with WPL, acquired approximately 60 MW of West Riverside in January 2018, and are funding their share of capital expenditures during construction. As part of the electric cooperatives’ acquisitions, the current wholesale power supply agreements with the various electric cooperatives were extended by at least four years until 2026 with automatic continuation of such agreements unless terminated by either party, with a five -year notice requirement. Wind Generation - IPL’s Expansion of Wind Generation - IPL currently plans to add up to 1,000 MW of new wind generation to its existing generation portfolio. These wind projects are expected to be placed into service in 2019 and 2020. As of September 30, 2018 , Alliant Energy and IPL recorded capitalized expenditures of $645 million and AFUDC of $33 million for this expansion of wind generation in “Property, plant and equipment, net” on their balance sheets. WPL’s Acquisition of Forward Wind Energy Center (FWEC) - In January 2018 and March 2018, WPL received approval from FERC and the PSCW, respectively, to acquire a partial ownership interest in the assets of FWEC, which is a 129 MW wind farm located in Wisconsin. In April 2018, WPL acquired 55 MW of the FWEC wind farm for approximately $74 million . As of the closing date, the estimated fair value of the assets purchased and the liabilities assumed by WPL were as follows (in millions): Property, plant and equipment, net $81 Liabilities 7 Net assets acquired $74 |
IPL [Member] | |
Property, Plant and Equipment [Line Items] | |
Property, Plant and Equipment | PROPERTY, PLANT AND EQUIPMENT Utility - Natural Gas-Fired Generation Project - WPL’s West Riverside Energy Center - WPL is currently constructing West Riverside, an approximate 730 MW natural gas-fired combined-cycle EGU. Construction began in 2016 and is currently expected to be completed by the end of 2019. As of September 30, 2018 , Alliant Energy and WPL recorded capitalized expenditures of $438 million and AFUDC of $35 million for West Riverside in “Property, plant and equipment, net” on their balance sheets. These capital expenditures reflect WPL’s portion of West Riverside. Certain electric cooperatives, which currently have wholesale power supply agreements with WPL, acquired approximately 60 MW of West Riverside in January 2018, and are funding their share of capital expenditures during construction. As part of the electric cooperatives’ acquisitions, the current wholesale power supply agreements with the various electric cooperatives were extended by at least four years until 2026 with automatic continuation of such agreements unless terminated by either party, with a five -year notice requirement. Wind Generation - IPL’s Expansion of Wind Generation - IPL currently plans to add up to 1,000 MW of new wind generation to its existing generation portfolio. These wind projects are expected to be placed into service in 2019 and 2020. As of September 30, 2018 , Alliant Energy and IPL recorded capitalized expenditures of $645 million and AFUDC of $33 million for this expansion of wind generation in “Property, plant and equipment, net” on their balance sheets. |
WPL [Member] | |
Property, Plant and Equipment [Line Items] | |
Property, Plant and Equipment | PROPERTY, PLANT AND EQUIPMENT Utility - Natural Gas-Fired Generation Project - WPL’s West Riverside Energy Center - WPL is currently constructing West Riverside, an approximate 730 MW natural gas-fired combined-cycle EGU. Construction began in 2016 and is currently expected to be completed by the end of 2019. As of September 30, 2018 , Alliant Energy and WPL recorded capitalized expenditures of $438 million and AFUDC of $35 million for West Riverside in “Property, plant and equipment, net” on their balance sheets. These capital expenditures reflect WPL’s portion of West Riverside. Certain electric cooperatives, which currently have wholesale power supply agreements with WPL, acquired approximately 60 MW of West Riverside in January 2018, and are funding their share of capital expenditures during construction. As part of the electric cooperatives’ acquisitions, the current wholesale power supply agreements with the various electric cooperatives were extended by at least four years until 2026 with automatic continuation of such agreements unless terminated by either party, with a five -year notice requirement. Wind Generation - IPL’s Expansion of Wind Generation - IPL currently plans to add up to 1,000 MW of new wind generation to its existing generation portfolio. These wind projects are expected to be placed into service in 2019 and 2020. As of September 30, 2018 , Alliant Energy and IPL recorded capitalized expenditures of $645 million and AFUDC of $33 million for this expansion of wind generation in “Property, plant and equipment, net” on their balance sheets. WPL’s Acquisition of Forward Wind Energy Center (FWEC) - In January 2018 and March 2018, WPL received approval from FERC and the PSCW, respectively, to acquire a partial ownership interest in the assets of FWEC, which is a 129 MW wind farm located in Wisconsin. In April 2018, WPL acquired 55 MW of the FWEC wind farm for approximately $74 million . As of the closing date, the estimated fair value of the assets purchased and the liabilities assumed by WPL were as follows (in millions): Property, plant and equipment, net $81 Liabilities 7 Net assets acquired $74 |
Receivables
Receivables | 9 Months Ended |
Sep. 30, 2018 | |
Receivables [Line Items] | |
Receivables | RECEIVABLES Sales of Accounts Receivable - IPL maintains a Receivables Purchase and Sale Agreement (Receivables Agreement) whereby it may sell its customer accounts receivables, unbilled revenues and certain other accounts receivables to a third party through wholly-owned and consolidated special purpose entities. In March 2018, IPL amended and extended through March 2021 the purchase commitment from the third party to which it sells its receivables. Effective April 2018, the limit on cash proceeds fluctuates between $90 million and $110 million . The transfers of receivables meet the criteria for sale accounting established by the transfer of financial assets accounting rules. As of September 30, 2018 , IPL had $109.0 million of available capacity under its sales of accounts receivable program. For the three and nine months ended September 30 , 2018 and 2017 , IPL’s costs incurred related to the sales of accounts receivable program were not material. IPL’s maximum and average outstanding cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program for the three and nine months ended September 30 were as follows (in millions): Three Months Nine Months 2018 2017 2018 2017 Maximum outstanding aggregate cash proceeds $110.0 $112.0 $116.0 $112.0 Average outstanding aggregate cash proceeds 36.4 66.2 49.8 58.7 The attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions): September 30, 2018 December 31, 2017 Customer accounts receivable $179.0 $133.8 Unbilled utility revenues 78.2 112.7 Other receivables 0.1 0.3 Receivables sold to third party 257.3 246.8 Less: cash proceeds 1.0 12.0 Deferred proceeds 256.3 234.8 Less: allowance for doubtful accounts 12.6 12.7 Fair value of deferred proceeds $243.7 $222.1 As of September 30, 2018 , outstanding receivables past due under the Receivables Agreement were $35.8 million . Additional attributes of IPL’s receivables sold under the Receivables Agreement for the three and nine months ended September 30 were as follows (in millions): Three Months Nine Months 2018 2017 2018 2017 Collections $549.5 $347.9 $1,550.2 $1,283.2 Write-offs, net of recoveries 4.9 3.5 12.9 10.4 |
IPL [Member] | |
Receivables [Line Items] | |
Receivables | RECEIVABLES Sales of Accounts Receivable - IPL maintains a Receivables Purchase and Sale Agreement (Receivables Agreement) whereby it may sell its customer accounts receivables, unbilled revenues and certain other accounts receivables to a third party through wholly-owned and consolidated special purpose entities. In March 2018, IPL amended and extended through March 2021 the purchase commitment from the third party to which it sells its receivables. Effective April 2018, the limit on cash proceeds fluctuates between $90 million and $110 million . The transfers of receivables meet the criteria for sale accounting established by the transfer of financial assets accounting rules. As of September 30, 2018 , IPL had $109.0 million of available capacity under its sales of accounts receivable program. For the three and nine months ended September 30 , 2018 and 2017 , IPL’s costs incurred related to the sales of accounts receivable program were not material. IPL’s maximum and average outstanding cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program for the three and nine months ended September 30 were as follows (in millions): Three Months Nine Months 2018 2017 2018 2017 Maximum outstanding aggregate cash proceeds $110.0 $112.0 $116.0 $112.0 Average outstanding aggregate cash proceeds 36.4 66.2 49.8 58.7 The attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions): September 30, 2018 December 31, 2017 Customer accounts receivable $179.0 $133.8 Unbilled utility revenues 78.2 112.7 Other receivables 0.1 0.3 Receivables sold to third party 257.3 246.8 Less: cash proceeds 1.0 12.0 Deferred proceeds 256.3 234.8 Less: allowance for doubtful accounts 12.6 12.7 Fair value of deferred proceeds $243.7 $222.1 As of September 30, 2018 , outstanding receivables past due under the Receivables Agreement were $35.8 million . Additional attributes of IPL’s receivables sold under the Receivables Agreement for the three and nine months ended September 30 were as follows (in millions): Three Months Nine Months 2018 2017 2018 2017 Collections $549.5 $347.9 $1,550.2 $1,283.2 Write-offs, net of recoveries 4.9 3.5 12.9 10.4 |
Investments
Investments | 9 Months Ended |
Sep. 30, 2018 | |
Schedule of Investments [Line Items] | |
Investments | INVESTMENTS Unconsolidated Equity Investments - Alliant Energy’s equity (income) loss from unconsolidated investments accounted for under the equity method of accounting for the three and nine months ended September 30 was as follows (in millions): Three Months Nine Months 2018 2017 2018 2017 ATC Holdings ($8.9 ) ($10.1 ) ($25.4 ) ($32.7 ) Non-utility wind farm in Oklahoma 0.1 0.2 (14.5 ) 0.2 Other (1.0 ) (0.2 ) (1.7 ) (0.4 ) ($9.8 ) ($10.1 ) ($41.6 ) ($32.9 ) Non-utility Wind Farm in Oklahoma - Alliant Energy’s interest in a non-utility wind farm in Oklahoma commenced in July 2017. As a result, there was no corresponding equity income recognized during the first half of 2017. The equity income recognized during the nine months ended September 30, 2018 was primarily related to the impacts of Federal Tax Reform. The liquidation method utilized to recognize Alliant Energy’s share of the wind farm’s earnings includes utilizing the federal income tax rate in effect as of the end of the measurement period. The lower federal income tax rate effective as of January 1, 2018 resulted in an acceleration of earnings attributable to Alliant Energy’s interest in the Oklahoma wind farm. This increase in earnings is expected to reverse over time. |
Common Equity
Common Equity | 9 Months Ended |
Sep. 30, 2018 | |
Common Equity [Line Items] | |
Common Equity | COMMON EQUITY Common Share Activity - A summary of Alliant Energy’s common stock activity was as follows: Shares outstanding, January 1, 2018 231,348,646 At-the-market offering program 4,171,013 Shareowner Direct Plan issuances 450,133 Equity-based compensation plans ( Note 10(b) ) 5,078 Other (38,423 ) Shares outstanding, September 30, 2018 235,936,447 Dividends declared per common share for Alliant Energy were $0.335 and $1.005 for the three and nine months ended September 30, 2018 , and $0.315 and $0.945 for the three and nine months ended September 30, 2017 . At-the-market Offering Program - In May 2018, Alliant Energy filed a prospectus supplement under which it may sell up to $175 million of its common stock through an at-the-market offering program. As of September 30, 2018 , Alliant Energy issued 4,171,013 shares of common stock through this program and received cash proceeds of $173 million , net of $2 million in fees and commissions. The proceeds from the issuances of common stock were used for general corporate purposes. Alliant Energy currently has no plans to issue any additional common stock through this at-the-market offering program. Comprehensive Income - For the three and nine months ended September 30, 2018 and 2017 , Alliant Energy’s other comprehensive income was not material; therefore, its comprehensive income was substantially equal to its net income and its comprehensive income attributable to Alliant Energy common shareowners was substantially equal to its net income attributable to Alliant Energy common shareowners for such periods. For the three and nine months ended September 30, 2018 and 2017 , IPL and WPL had no other comprehensive income; therefore, their comprehensive income was equal to their net income and their comprehensive income available for common stock was equal to their earnings available for common stock for such periods. |
IPL [Member] | |
Common Equity [Line Items] | |
Common Equity | COMMON EQUITY Common Share Activity - A summary of Alliant Energy’s common stock activity was as follows: Shares outstanding, January 1, 2018 231,348,646 At-the-market offering program 4,171,013 Shareowner Direct Plan issuances 450,133 Equity-based compensation plans ( Note 10(b) ) 5,078 Other (38,423 ) Shares outstanding, September 30, 2018 235,936,447 Dividends declared per common share for Alliant Energy were $0.335 and $1.005 for the three and nine months ended September 30, 2018 , and $0.315 and $0.945 for the three and nine months ended September 30, 2017 . At-the-market Offering Program - In May 2018, Alliant Energy filed a prospectus supplement under which it may sell up to $175 million of its common stock through an at-the-market offering program. As of September 30, 2018 , Alliant Energy issued 4,171,013 shares of common stock through this program and received cash proceeds of $173 million , net of $2 million in fees and commissions. The proceeds from the issuances of common stock were used for general corporate purposes. Alliant Energy currently has no plans to issue any additional common stock through this at-the-market offering program. Comprehensive Income - For the three and nine months ended September 30, 2018 and 2017 , Alliant Energy’s other comprehensive income was not material; therefore, its comprehensive income was substantially equal to its net income and its comprehensive income attributable to Alliant Energy common shareowners was substantially equal to its net income attributable to Alliant Energy common shareowners for such periods. For the three and nine months ended September 30, 2018 and 2017 , IPL and WPL had no other comprehensive income; therefore, their comprehensive income was equal to their net income and their comprehensive income available for common stock was equal to their earnings available for common stock for such periods. |
WPL [Member] | |
Common Equity [Line Items] | |
Common Equity | COMMON EQUITY Common Share Activity - A summary of Alliant Energy’s common stock activity was as follows: Shares outstanding, January 1, 2018 231,348,646 At-the-market offering program 4,171,013 Shareowner Direct Plan issuances 450,133 Equity-based compensation plans ( Note 10(b) ) 5,078 Other (38,423 ) Shares outstanding, September 30, 2018 235,936,447 Dividends declared per common share for Alliant Energy were $0.335 and $1.005 for the three and nine months ended September 30, 2018 , and $0.315 and $0.945 for the three and nine months ended September 30, 2017 . At-the-market Offering Program - In May 2018, Alliant Energy filed a prospectus supplement under which it may sell up to $175 million of its common stock through an at-the-market offering program. As of September 30, 2018 , Alliant Energy issued 4,171,013 shares of common stock through this program and received cash proceeds of $173 million , net of $2 million in fees and commissions. The proceeds from the issuances of common stock were used for general corporate purposes. Alliant Energy currently has no plans to issue any additional common stock through this at-the-market offering program. Comprehensive Income - For the three and nine months ended September 30, 2018 and 2017 , Alliant Energy’s other comprehensive income was not material; therefore, its comprehensive income was substantially equal to its net income and its comprehensive income attributable to Alliant Energy common shareowners was substantially equal to its net income attributable to Alliant Energy common shareowners for such periods. For the three and nine months ended September 30, 2018 and 2017 , IPL and WPL had no other comprehensive income; therefore, their comprehensive income was equal to their net income and their comprehensive income available for common stock was equal to their earnings available for common stock for such periods. |
Debt
Debt | 9 Months Ended |
Sep. 30, 2018 | |
Debt [Line Items] | |
Debt | DEBT Note 7(a) Short-term Debt - Information regarding commercial paper classified as short-term debt was as follows (dollars in millions): September 30, 2018 Alliant Energy IPL WPL Commercial paper outstanding $136.8 $— $38.4 Commercial paper weighted average interest rates 2.4% N/A 2.2% Available credit facility capacity $863.2 $250.0 $311.6 Alliant Energy IPL WPL Three Months Ended September 30 2018 2017 2018 2017 2018 2017 Maximum amount outstanding (based on daily outstanding balances) $153.3 $424.4 $— $20.0 $75.4 $271.2 Average amount outstanding (based on daily outstanding balances) $80.8 $386.2 $— $0.4 $23.1 $217.0 Weighted average interest rates 2.2% 1.3% N/A 1.4% 2.0% 1.1% Nine Months Ended September 30 Maximum amount outstanding (based on daily outstanding balances) $446.5 $424.4 $31.4 $20.0 $109.4 $271.2 Average amount outstanding (based on daily outstanding balances) $207.6 $323.9 $1.7 $0.5 $26.6 $144.2 Weighted average interest rates 2.1% 1.1% 2.3% 1.2% 1.9% 1.0% As discussed in Note 7(b) , in June 2018, AEF retired its $95 million term loan credit agreement expiring in 2018. NOTE 7(b) Long-term Debt - In April 2018, AEF entered into a $300 million variable-rate ( 2.8% at September 30, 2018 ) term loan credit agreement (with Alliant Energy as guarantor) and used the proceeds from borrowings under this agreement for general corporate purposes. AEF’s term loan credit agreement expires in April 2020 and includes substantially the same financial covenants that are included in Alliant Energy’s credit facility agreement. In June 2018, AEF (with Alliant Energy as guarantor) issued $400 million of 3.75% senior notes due 2023 and $300 million of 4.25% senior notes due 2028. The proceeds from the issuances were used by AEF to retire its $500 million and $95 million variable-rate term loan credit agreements expiring in 2018, to reduce Alliant Energy’s outstanding commercial paper and for general corporate purposes. In September 2018, IPL issued $500 million of 4.1% senior debentures due 2028. The senior debentures were issued as green bonds, and all of the net proceeds were allocated for the construction and development of wind and solar projects. In September 2018 and October 2018, IPL retired its $100 million ( 5.875% ) and $250 million ( 7.25% ) senior debentures, respectively. |
IPL [Member] | |
Debt [Line Items] | |
Debt | DEBT Note 7(a) Short-term Debt - Information regarding commercial paper classified as short-term debt was as follows (dollars in millions): September 30, 2018 Alliant Energy IPL WPL Commercial paper outstanding $136.8 $— $38.4 Commercial paper weighted average interest rates 2.4% N/A 2.2% Available credit facility capacity $863.2 $250.0 $311.6 Alliant Energy IPL WPL Three Months Ended September 30 2018 2017 2018 2017 2018 2017 Maximum amount outstanding (based on daily outstanding balances) $153.3 $424.4 $— $20.0 $75.4 $271.2 Average amount outstanding (based on daily outstanding balances) $80.8 $386.2 $— $0.4 $23.1 $217.0 Weighted average interest rates 2.2% 1.3% N/A 1.4% 2.0% 1.1% Nine Months Ended September 30 Maximum amount outstanding (based on daily outstanding balances) $446.5 $424.4 $31.4 $20.0 $109.4 $271.2 Average amount outstanding (based on daily outstanding balances) $207.6 $323.9 $1.7 $0.5 $26.6 $144.2 Weighted average interest rates 2.1% 1.1% 2.3% 1.2% 1.9% 1.0% As discussed in Note 7(b) , in June 2018, AEF retired its $95 million term loan credit agreement expiring in 2018. NOTE 7(b) Long-term Debt - In April 2018, AEF entered into a $300 million variable-rate ( 2.8% at September 30, 2018 ) term loan credit agreement (with Alliant Energy as guarantor) and used the proceeds from borrowings under this agreement for general corporate purposes. AEF’s term loan credit agreement expires in April 2020 and includes substantially the same financial covenants that are included in Alliant Energy’s credit facility agreement. In June 2018, AEF (with Alliant Energy as guarantor) issued $400 million of 3.75% senior notes due 2023 and $300 million of 4.25% senior notes due 2028. The proceeds from the issuances were used by AEF to retire its $500 million and $95 million variable-rate term loan credit agreements expiring in 2018, to reduce Alliant Energy’s outstanding commercial paper and for general corporate purposes. In September 2018, IPL issued $500 million of 4.1% senior debentures due 2028. The senior debentures were issued as green bonds, and all of the net proceeds were allocated for the construction and development of wind and solar projects. In September 2018 and October 2018, IPL retired its $100 million ( 5.875% ) and $250 million ( 7.25% ) senior debentures, respectively. |
WPL [Member] | |
Debt [Line Items] | |
Debt | DEBT Note 7(a) Short-term Debt - Information regarding commercial paper classified as short-term debt was as follows (dollars in millions): September 30, 2018 Alliant Energy IPL WPL Commercial paper outstanding $136.8 $— $38.4 Commercial paper weighted average interest rates 2.4% N/A 2.2% Available credit facility capacity $863.2 $250.0 $311.6 Alliant Energy IPL WPL Three Months Ended September 30 2018 2017 2018 2017 2018 2017 Maximum amount outstanding (based on daily outstanding balances) $153.3 $424.4 $— $20.0 $75.4 $271.2 Average amount outstanding (based on daily outstanding balances) $80.8 $386.2 $— $0.4 $23.1 $217.0 Weighted average interest rates 2.2% 1.3% N/A 1.4% 2.0% 1.1% Nine Months Ended September 30 Maximum amount outstanding (based on daily outstanding balances) $446.5 $424.4 $31.4 $20.0 $109.4 $271.2 Average amount outstanding (based on daily outstanding balances) $207.6 $323.9 $1.7 $0.5 $26.6 $144.2 Weighted average interest rates 2.1% 1.1% 2.3% 1.2% 1.9% 1.0% |
Revenues Revenues
Revenues Revenues | 9 Months Ended |
Sep. 30, 2018 | |
Disaggregation of Revenue [Line Items] | |
Revenue from Contract with Customer | REVENUES Revenues from Alliant Energy’s, IPL’s and WPL’s utility businesses are primarily from electric and gas sales provided to customers based on approved tariffs or specific contracts with customers. IPL’s and WPL’s primary performance obligations under such arrangements are to deliver electricity and gas, and their customers simultaneously receive and consume the electricity and gas. For such arrangements, revenues are recognized equivalent to the value of the electricity or gas supplied during each period, including amounts billed during each period and changes in amounts estimated to be billed at the end of each period. IPL and WPL apply the right to invoice method to measure progress towards completing performance obligations to transfer electricity and gas to their customers. IPL provides retail electric and gas service to customers in Iowa, and WPL provides retail and wholesale electric and retail gas service to customers in Wisconsin. IPL also sells electricity to wholesale customers in Minnesota, Illinois and Iowa, as well as steam from its Prairie Creek Generating Station to high-pressure steam customers in Iowa. IPL’s and WPL’s retail electric and gas revenues include sales to residential, commercial and industrial customers. IPL’s and WPL’s retail electric and gas customer prices are based on IPL’s and WPL’s cost of service and are determined through general rate review proceedings and various tariff filings with the IUB and PSCW, respectively. Such tariff-based services provide electricity or gas to customers without a defined contractual term. IPL and WPL have wholesale electric market-based rate authority from FERC allowing them to participate in wholesale energy markets (e.g. MISO) and transact directly with third parties. This authority from FERC allows sales of electricity referred to as bulk power sales based on current market values. FERC also allows IPL and WPL to enter into power supply agreements with municipalities and rural electric cooperatives with defined contractual terms, which include standard pricing mechanisms that are detailed in current tariffs accepted by FERC through wholesale rate review proceedings. Revenues from Alliant Energy’s non-utility business customers are primarily from its Transportation business, which includes a short-line railway that provides freight service between Cedar Rapids, Iowa and Iowa City, Iowa; a barge terminal and hauling services on the Mississippi River; and other transfer and storage services. As of September 30, 2018 , revenue expected to be recognized in any future year related to remaining performance obligations is not material, as the majority of revenues are recognized as services are rendered or commodities are delivered, and are from contracts with durations of less than one year. Alliant Energy, IPL and WPL do not have any material contract assets or contract liabilities, or contract acquisition fulfillment costs. Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions): Alliant Energy IPL WPL Three Months Ended September 30 2018 2017 2018 2017 2018 2017 Electric Utility: Retail - residential $312.9 $296.4 $180.1 $168.5 $132.8 $127.9 Retail - commercial 215.4 205.9 146.0 137.5 69.4 68.4 Retail - industrial 247.8 243.4 141.4 137.3 106.4 106.1 Wholesale 50.0 63.5 18.2 26.7 31.8 36.8 Bulk power and other 35.1 31.4 23.5 19.0 11.6 12.4 Total Electric Utility 861.2 840.6 509.2 489.0 352.0 351.6 Gas Utility: Retail - residential 21.8 21.5 12.6 12.0 9.2 9.5 Retail - commercial 11.0 12.9 6.4 7.8 4.6 5.1 Retail - industrial 3.0 3.0 2.0 2.2 1.0 0.8 Transportation/other 9.0 8.4 5.7 5.4 3.3 3.0 Total Gas Utility 44.8 45.8 26.7 27.4 18.1 18.4 Other Utility: Steam 8.7 8.3 8.7 8.3 — — Other utility 3.6 2.9 3.0 2.7 0.6 0.2 Total Other Utility 12.3 11.2 11.7 11.0 0.6 0.2 Non-Utility and Other: Transportation and other 10.3 9.3 — — — — Total Non-Utility and Other 10.3 9.3 — — — — Total revenues $928.6 $906.9 $547.6 $527.4 $370.7 $370.2 Alliant Energy IPL WPL Nine Months Ended September 30 2018 2017 2018 2017 2018 2017 Electric Utility: Retail - residential $820.6 $766.9 $461.6 $414.2 $359.0 $352.7 Retail - commercial 561.7 537.3 371.8 340.6 189.9 196.7 Retail - industrial 675.1 646.2 385.0 350.7 290.1 295.5 Wholesale 146.9 186.3 56.4 71.3 90.5 115.0 Bulk power and other 91.9 62.4 62.2 40.8 29.7 21.6 Total Electric Utility 2,296.2 2,199.1 1,337.0 1,217.6 959.2 981.5 Gas Utility: Retail - residential 170.1 145.1 100.9 78.7 69.2 66.4 Retail - commercial 87.3 81.4 49.8 44.4 37.5 37.0 Retail - industrial 11.4 10.4 6.1 6.8 5.3 3.6 Transportation/other 30.2 25.8 20.2 17.3 10.0 8.5 Total Gas Utility 299.0 262.7 177.0 147.2 122.0 115.5 Other Utility: Steam 26.5 25.3 26.5 25.3 — — Other utility 9.7 9.1 7.7 8.0 2.0 1.1 Total Other Utility 36.2 34.4 34.2 33.3 2.0 1.1 Non-Utility and Other: Transportation and other 29.6 29.9 — — — — Total Non-Utility and Other 29.6 29.9 — — — — Total revenues $2,661.0 $2,526.1 $1,548.2 $1,398.1 $1,083.2 $1,098.1 |
IPL [Member] | |
Disaggregation of Revenue [Line Items] | |
Revenue from Contract with Customer | REVENUES Revenues from Alliant Energy’s, IPL’s and WPL’s utility businesses are primarily from electric and gas sales provided to customers based on approved tariffs or specific contracts with customers. IPL’s and WPL’s primary performance obligations under such arrangements are to deliver electricity and gas, and their customers simultaneously receive and consume the electricity and gas. For such arrangements, revenues are recognized equivalent to the value of the electricity or gas supplied during each period, including amounts billed during each period and changes in amounts estimated to be billed at the end of each period. IPL and WPL apply the right to invoice method to measure progress towards completing performance obligations to transfer electricity and gas to their customers. IPL provides retail electric and gas service to customers in Iowa, and WPL provides retail and wholesale electric and retail gas service to customers in Wisconsin. IPL also sells electricity to wholesale customers in Minnesota, Illinois and Iowa, as well as steam from its Prairie Creek Generating Station to high-pressure steam customers in Iowa. IPL’s and WPL’s retail electric and gas revenues include sales to residential, commercial and industrial customers. IPL’s and WPL’s retail electric and gas customer prices are based on IPL’s and WPL’s cost of service and are determined through general rate review proceedings and various tariff filings with the IUB and PSCW, respectively. Such tariff-based services provide electricity or gas to customers without a defined contractual term. IPL and WPL have wholesale electric market-based rate authority from FERC allowing them to participate in wholesale energy markets (e.g. MISO) and transact directly with third parties. This authority from FERC allows sales of electricity referred to as bulk power sales based on current market values. FERC also allows IPL and WPL to enter into power supply agreements with municipalities and rural electric cooperatives with defined contractual terms, which include standard pricing mechanisms that are detailed in current tariffs accepted by FERC through wholesale rate review proceedings. Revenues from Alliant Energy’s non-utility business customers are primarily from its Transportation business, which includes a short-line railway that provides freight service between Cedar Rapids, Iowa and Iowa City, Iowa; a barge terminal and hauling services on the Mississippi River; and other transfer and storage services. As of September 30, 2018 , revenue expected to be recognized in any future year related to remaining performance obligations is not material, as the majority of revenues are recognized as services are rendered or commodities are delivered, and are from contracts with durations of less than one year. Alliant Energy, IPL and WPL do not have any material contract assets or contract liabilities, or contract acquisition fulfillment costs. Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions): Alliant Energy IPL WPL Three Months Ended September 30 2018 2017 2018 2017 2018 2017 Electric Utility: Retail - residential $312.9 $296.4 $180.1 $168.5 $132.8 $127.9 Retail - commercial 215.4 205.9 146.0 137.5 69.4 68.4 Retail - industrial 247.8 243.4 141.4 137.3 106.4 106.1 Wholesale 50.0 63.5 18.2 26.7 31.8 36.8 Bulk power and other 35.1 31.4 23.5 19.0 11.6 12.4 Total Electric Utility 861.2 840.6 509.2 489.0 352.0 351.6 Gas Utility: Retail - residential 21.8 21.5 12.6 12.0 9.2 9.5 Retail - commercial 11.0 12.9 6.4 7.8 4.6 5.1 Retail - industrial 3.0 3.0 2.0 2.2 1.0 0.8 Transportation/other 9.0 8.4 5.7 5.4 3.3 3.0 Total Gas Utility 44.8 45.8 26.7 27.4 18.1 18.4 Other Utility: Steam 8.7 8.3 8.7 8.3 — — Other utility 3.6 2.9 3.0 2.7 0.6 0.2 Total Other Utility 12.3 11.2 11.7 11.0 0.6 0.2 Non-Utility and Other: Transportation and other 10.3 9.3 — — — — Total Non-Utility and Other 10.3 9.3 — — — — Total revenues $928.6 $906.9 $547.6 $527.4 $370.7 $370.2 Alliant Energy IPL WPL Nine Months Ended September 30 2018 2017 2018 2017 2018 2017 Electric Utility: Retail - residential $820.6 $766.9 $461.6 $414.2 $359.0 $352.7 Retail - commercial 561.7 537.3 371.8 340.6 189.9 196.7 Retail - industrial 675.1 646.2 385.0 350.7 290.1 295.5 Wholesale 146.9 186.3 56.4 71.3 90.5 115.0 Bulk power and other 91.9 62.4 62.2 40.8 29.7 21.6 Total Electric Utility 2,296.2 2,199.1 1,337.0 1,217.6 959.2 981.5 Gas Utility: Retail - residential 170.1 145.1 100.9 78.7 69.2 66.4 Retail - commercial 87.3 81.4 49.8 44.4 37.5 37.0 Retail - industrial 11.4 10.4 6.1 6.8 5.3 3.6 Transportation/other 30.2 25.8 20.2 17.3 10.0 8.5 Total Gas Utility 299.0 262.7 177.0 147.2 122.0 115.5 Other Utility: Steam 26.5 25.3 26.5 25.3 — — Other utility 9.7 9.1 7.7 8.0 2.0 1.1 Total Other Utility 36.2 34.4 34.2 33.3 2.0 1.1 Non-Utility and Other: Transportation and other 29.6 29.9 — — — — Total Non-Utility and Other 29.6 29.9 — — — — Total revenues $2,661.0 $2,526.1 $1,548.2 $1,398.1 $1,083.2 $1,098.1 |
WPL [Member] | |
Disaggregation of Revenue [Line Items] | |
Revenue from Contract with Customer | REVENUES Revenues from Alliant Energy’s, IPL’s and WPL’s utility businesses are primarily from electric and gas sales provided to customers based on approved tariffs or specific contracts with customers. IPL’s and WPL’s primary performance obligations under such arrangements are to deliver electricity and gas, and their customers simultaneously receive and consume the electricity and gas. For such arrangements, revenues are recognized equivalent to the value of the electricity or gas supplied during each period, including amounts billed during each period and changes in amounts estimated to be billed at the end of each period. IPL and WPL apply the right to invoice method to measure progress towards completing performance obligations to transfer electricity and gas to their customers. IPL provides retail electric and gas service to customers in Iowa, and WPL provides retail and wholesale electric and retail gas service to customers in Wisconsin. IPL also sells electricity to wholesale customers in Minnesota, Illinois and Iowa, as well as steam from its Prairie Creek Generating Station to high-pressure steam customers in Iowa. IPL’s and WPL’s retail electric and gas revenues include sales to residential, commercial and industrial customers. IPL’s and WPL’s retail electric and gas customer prices are based on IPL’s and WPL’s cost of service and are determined through general rate review proceedings and various tariff filings with the IUB and PSCW, respectively. Such tariff-based services provide electricity or gas to customers without a defined contractual term. IPL and WPL have wholesale electric market-based rate authority from FERC allowing them to participate in wholesale energy markets (e.g. MISO) and transact directly with third parties. This authority from FERC allows sales of electricity referred to as bulk power sales based on current market values. FERC also allows IPL and WPL to enter into power supply agreements with municipalities and rural electric cooperatives with defined contractual terms, which include standard pricing mechanisms that are detailed in current tariffs accepted by FERC through wholesale rate review proceedings. Revenues from Alliant Energy’s non-utility business customers are primarily from its Transportation business, which includes a short-line railway that provides freight service between Cedar Rapids, Iowa and Iowa City, Iowa; a barge terminal and hauling services on the Mississippi River; and other transfer and storage services. As of September 30, 2018 , revenue expected to be recognized in any future year related to remaining performance obligations is not material, as the majority of revenues are recognized as services are rendered or commodities are delivered, and are from contracts with durations of less than one year. Alliant Energy, IPL and WPL do not have any material contract assets or contract liabilities, or contract acquisition fulfillment costs. Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions): Alliant Energy IPL WPL Three Months Ended September 30 2018 2017 2018 2017 2018 2017 Electric Utility: Retail - residential $312.9 $296.4 $180.1 $168.5 $132.8 $127.9 Retail - commercial 215.4 205.9 146.0 137.5 69.4 68.4 Retail - industrial 247.8 243.4 141.4 137.3 106.4 106.1 Wholesale 50.0 63.5 18.2 26.7 31.8 36.8 Bulk power and other 35.1 31.4 23.5 19.0 11.6 12.4 Total Electric Utility 861.2 840.6 509.2 489.0 352.0 351.6 Gas Utility: Retail - residential 21.8 21.5 12.6 12.0 9.2 9.5 Retail - commercial 11.0 12.9 6.4 7.8 4.6 5.1 Retail - industrial 3.0 3.0 2.0 2.2 1.0 0.8 Transportation/other 9.0 8.4 5.7 5.4 3.3 3.0 Total Gas Utility 44.8 45.8 26.7 27.4 18.1 18.4 Other Utility: Steam 8.7 8.3 8.7 8.3 — — Other utility 3.6 2.9 3.0 2.7 0.6 0.2 Total Other Utility 12.3 11.2 11.7 11.0 0.6 0.2 Non-Utility and Other: Transportation and other 10.3 9.3 — — — — Total Non-Utility and Other 10.3 9.3 — — — — Total revenues $928.6 $906.9 $547.6 $527.4 $370.7 $370.2 Alliant Energy IPL WPL Nine Months Ended September 30 2018 2017 2018 2017 2018 2017 Electric Utility: Retail - residential $820.6 $766.9 $461.6 $414.2 $359.0 $352.7 Retail - commercial 561.7 537.3 371.8 340.6 189.9 196.7 Retail - industrial 675.1 646.2 385.0 350.7 290.1 295.5 Wholesale 146.9 186.3 56.4 71.3 90.5 115.0 Bulk power and other 91.9 62.4 62.2 40.8 29.7 21.6 Total Electric Utility 2,296.2 2,199.1 1,337.0 1,217.6 959.2 981.5 Gas Utility: Retail - residential 170.1 145.1 100.9 78.7 69.2 66.4 Retail - commercial 87.3 81.4 49.8 44.4 37.5 37.0 Retail - industrial 11.4 10.4 6.1 6.8 5.3 3.6 Transportation/other 30.2 25.8 20.2 17.3 10.0 8.5 Total Gas Utility 299.0 262.7 177.0 147.2 122.0 115.5 Other Utility: Steam 26.5 25.3 26.5 25.3 — — Other utility 9.7 9.1 7.7 8.0 2.0 1.1 Total Other Utility 36.2 34.4 34.2 33.3 2.0 1.1 Non-Utility and Other: Transportation and other 29.6 29.9 — — — — Total Non-Utility and Other 29.6 29.9 — — — — Total revenues $2,661.0 $2,526.1 $1,548.2 $1,398.1 $1,083.2 $1,098.1 |
Income Taxes
Income Taxes | 9 Months Ended |
Sep. 30, 2018 | |
Income Taxes [Line Items] | |
Income Taxes | INCOME TAXES Income Tax Rates - The overall income tax rates shown in the following table were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes. Alliant Energy IPL WPL Three Months Ended September 30 2018 2017 2018 2017 2018 2017 Statutory federal income tax rate 21.0 % 35.0 % 21.0 % 35.0 % 21.0 % 35.0 % State income taxes, net of federal benefits 6.9 5.7 7.7 6.5 6.2 5.2 Effect of rate-making on property-related differences (6.3 ) (10.1 ) (11.5 ) (22.6 ) (2.1 ) (1.9 ) Production tax credits (5.4 ) (6.2 ) (5.5 ) (7.0 ) (6.4 ) (7.0 ) Adjustment for prior period taxes (5.7 ) (2.0 ) (10.2 ) (3.5 ) — 0.8 IPL’s tax benefit riders (2.3 ) (8.3 ) (4.8 ) (20.9 ) — — Federal Tax Reform adjustments (2.5 ) — (0.9 ) — (6.4 ) — Other items, net (0.4 ) (0.9 ) (0.6 ) (0.7 ) (0.5 ) (0.5 ) Overall income tax rate 5.3 % 13.2 % (4.8 %) (13.2 %) 11.8 % 31.6 % Alliant Energy IPL WPL Nine Months Ended September 30 2018 2017 2018 2017 2018 2017 Statutory federal income tax rate 21.0 % 35.0 % 21.0 % 35.0 % 21.0 % 35.0 % State income taxes, net of federal benefits 6.9 5.6 7.7 6.5 6.2 5.1 Effect of rate-making on property-related differences (6.7 ) (9.1 ) (12.0 ) (20.6 ) (2.3 ) (1.8 ) Production tax credits (5.4 ) (6.0 ) (5.4 ) (6.8 ) (6.6 ) (7.0 ) Adjustment for prior period taxes (2.6 ) (1.3 ) (5.4 ) (3.3 ) — 0.3 IPL’s tax benefit riders (2.2 ) (8.1 ) (4.6 ) (20.1 ) — — Federal Tax Reform adjustments (1.2 ) — (0.5 ) — (2.8 ) — Other items, net (1.0 ) (1.2 ) (1.0 ) (0.5 ) (1.3 ) (0.5 ) Overall income tax rate 8.8 % 14.9 % (0.2 %) (9.8 %) 14.2 % 31.1 % Federal Tax Reform Adjustments - In December 2017, Federal Tax Reform was enacted, which had a material impact on Alliant Energy’s, IPL’s and WPL’s financial statements in the fourth quarter of 2017 since changes in tax laws must be recognized in the period in which the law was enacted. During the third quarter of 2018, additional rules were issued, including clarifications of the treatment of bonus depreciation deductions, which impacted the federal income tax return for the calendar year 2017. As result of these clarifying rules, Alliant Energy, IPL and WPL recorded tax benefits of $5.6 million , $1.1 million and $5.5 million , respectively, in the third quarter of 2018. Deferred Tax Assets and Liabilities - For the nine months ended September 30 , 2018 , Alliant Energy’s, IPL’s and WPL’s deferred tax liabilities increased $96.8 million , $22.3 million and $57.2 million , respectively. The increases were primarily due to property-related differences, which were partially offset by increases in federal credit carryforwards. Alliant Energy’s and IPL’s increases were also partially offset by the effects of Iowa tax reform, which is discussed in Note 2 . WPL’s increase was also partially due to the utilization of federal net operating losses. Carryforwards - At September 30, 2018 , carryforwards and expiration dates were estimated as follows (in millions): Range of Expiration Dates Alliant Energy IPL WPL Federal net operating losses 2030-2037 $804 $563 $144 State net operating losses 2018-2038 765 13 2 Federal tax credits 2022-2038 290 129 143 |
IPL [Member] | |
Income Taxes [Line Items] | |
Income Taxes | INCOME TAXES Income Tax Rates - The overall income tax rates shown in the following table were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes. Alliant Energy IPL WPL Three Months Ended September 30 2018 2017 2018 2017 2018 2017 Statutory federal income tax rate 21.0 % 35.0 % 21.0 % 35.0 % 21.0 % 35.0 % State income taxes, net of federal benefits 6.9 5.7 7.7 6.5 6.2 5.2 Effect of rate-making on property-related differences (6.3 ) (10.1 ) (11.5 ) (22.6 ) (2.1 ) (1.9 ) Production tax credits (5.4 ) (6.2 ) (5.5 ) (7.0 ) (6.4 ) (7.0 ) Adjustment for prior period taxes (5.7 ) (2.0 ) (10.2 ) (3.5 ) — 0.8 IPL’s tax benefit riders (2.3 ) (8.3 ) (4.8 ) (20.9 ) — — Federal Tax Reform adjustments (2.5 ) — (0.9 ) — (6.4 ) — Other items, net (0.4 ) (0.9 ) (0.6 ) (0.7 ) (0.5 ) (0.5 ) Overall income tax rate 5.3 % 13.2 % (4.8 %) (13.2 %) 11.8 % 31.6 % Alliant Energy IPL WPL Nine Months Ended September 30 2018 2017 2018 2017 2018 2017 Statutory federal income tax rate 21.0 % 35.0 % 21.0 % 35.0 % 21.0 % 35.0 % State income taxes, net of federal benefits 6.9 5.6 7.7 6.5 6.2 5.1 Effect of rate-making on property-related differences (6.7 ) (9.1 ) (12.0 ) (20.6 ) (2.3 ) (1.8 ) Production tax credits (5.4 ) (6.0 ) (5.4 ) (6.8 ) (6.6 ) (7.0 ) Adjustment for prior period taxes (2.6 ) (1.3 ) (5.4 ) (3.3 ) — 0.3 IPL’s tax benefit riders (2.2 ) (8.1 ) (4.6 ) (20.1 ) — — Federal Tax Reform adjustments (1.2 ) — (0.5 ) — (2.8 ) — Other items, net (1.0 ) (1.2 ) (1.0 ) (0.5 ) (1.3 ) (0.5 ) Overall income tax rate 8.8 % 14.9 % (0.2 %) (9.8 %) 14.2 % 31.1 % Federal Tax Reform Adjustments - In December 2017, Federal Tax Reform was enacted, which had a material impact on Alliant Energy’s, IPL’s and WPL’s financial statements in the fourth quarter of 2017 since changes in tax laws must be recognized in the period in which the law was enacted. During the third quarter of 2018, additional rules were issued, including clarifications of the treatment of bonus depreciation deductions, which impacted the federal income tax return for the calendar year 2017. As result of these clarifying rules, Alliant Energy, IPL and WPL recorded tax benefits of $5.6 million , $1.1 million and $5.5 million , respectively, in the third quarter of 2018. Deferred Tax Assets and Liabilities - For the nine months ended September 30 , 2018 , Alliant Energy’s, IPL’s and WPL’s deferred tax liabilities increased $96.8 million , $22.3 million and $57.2 million , respectively. The increases were primarily due to property-related differences, which were partially offset by increases in federal credit carryforwards. Alliant Energy’s and IPL’s increases were also partially offset by the effects of Iowa tax reform, which is discussed in Note 2 . WPL’s increase was also partially due to the utilization of federal net operating losses. Carryforwards - At September 30, 2018 , carryforwards and expiration dates were estimated as follows (in millions): Range of Expiration Dates Alliant Energy IPL WPL Federal net operating losses 2030-2037 $804 $563 $144 State net operating losses 2018-2038 765 13 2 Federal tax credits 2022-2038 290 129 143 |
WPL [Member] | |
Income Taxes [Line Items] | |
Income Taxes | INCOME TAXES Income Tax Rates - The overall income tax rates shown in the following table were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes. Alliant Energy IPL WPL Three Months Ended September 30 2018 2017 2018 2017 2018 2017 Statutory federal income tax rate 21.0 % 35.0 % 21.0 % 35.0 % 21.0 % 35.0 % State income taxes, net of federal benefits 6.9 5.7 7.7 6.5 6.2 5.2 Effect of rate-making on property-related differences (6.3 ) (10.1 ) (11.5 ) (22.6 ) (2.1 ) (1.9 ) Production tax credits (5.4 ) (6.2 ) (5.5 ) (7.0 ) (6.4 ) (7.0 ) Adjustment for prior period taxes (5.7 ) (2.0 ) (10.2 ) (3.5 ) — 0.8 IPL’s tax benefit riders (2.3 ) (8.3 ) (4.8 ) (20.9 ) — — Federal Tax Reform adjustments (2.5 ) — (0.9 ) — (6.4 ) — Other items, net (0.4 ) (0.9 ) (0.6 ) (0.7 ) (0.5 ) (0.5 ) Overall income tax rate 5.3 % 13.2 % (4.8 %) (13.2 %) 11.8 % 31.6 % Alliant Energy IPL WPL Nine Months Ended September 30 2018 2017 2018 2017 2018 2017 Statutory federal income tax rate 21.0 % 35.0 % 21.0 % 35.0 % 21.0 % 35.0 % State income taxes, net of federal benefits 6.9 5.6 7.7 6.5 6.2 5.1 Effect of rate-making on property-related differences (6.7 ) (9.1 ) (12.0 ) (20.6 ) (2.3 ) (1.8 ) Production tax credits (5.4 ) (6.0 ) (5.4 ) (6.8 ) (6.6 ) (7.0 ) Adjustment for prior period taxes (2.6 ) (1.3 ) (5.4 ) (3.3 ) — 0.3 IPL’s tax benefit riders (2.2 ) (8.1 ) (4.6 ) (20.1 ) — — Federal Tax Reform adjustments (1.2 ) — (0.5 ) — (2.8 ) — Other items, net (1.0 ) (1.2 ) (1.0 ) (0.5 ) (1.3 ) (0.5 ) Overall income tax rate 8.8 % 14.9 % (0.2 %) (9.8 %) 14.2 % 31.1 % Federal Tax Reform Adjustments - In December 2017, Federal Tax Reform was enacted, which had a material impact on Alliant Energy’s, IPL’s and WPL’s financial statements in the fourth quarter of 2017 since changes in tax laws must be recognized in the period in which the law was enacted. During the third quarter of 2018, additional rules were issued, including clarifications of the treatment of bonus depreciation deductions, which impacted the federal income tax return for the calendar year 2017. As result of these clarifying rules, Alliant Energy, IPL and WPL recorded tax benefits of $5.6 million , $1.1 million and $5.5 million , respectively, in the third quarter of 2018. Deferred Tax Assets and Liabilities - For the nine months ended September 30 , 2018 , Alliant Energy’s, IPL’s and WPL’s deferred tax liabilities increased $96.8 million , $22.3 million and $57.2 million , respectively. The increases were primarily due to property-related differences, which were partially offset by increases in federal credit carryforwards. Alliant Energy’s and IPL’s increases were also partially offset by the effects of Iowa tax reform, which is discussed in Note 2 . WPL’s increase was also partially due to the utilization of federal net operating losses. Carryforwards - At September 30, 2018 , carryforwards and expiration dates were estimated as follows (in millions): Range of Expiration Dates Alliant Energy IPL WPL Federal net operating losses 2030-2037 $804 $563 $144 State net operating losses 2018-2038 765 13 2 Federal tax credits 2022-2038 290 129 143 |
Benefit Plans
Benefit Plans | 9 Months Ended |
Sep. 30, 2018 | |
Benefit Plans | BENEFIT PLANS NOTE 10(a) Pension and Other Postretirement Benefits Plans - Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and nine months ended September 30 are included in the tables below (in millions). The service cost component of net periodic benefit costs is included in “Other operation and maintenance” expenses in the income statements and all other components of net periodic benefit costs are included in “Other (income) and deductions” in the income statements. In IPL’s and WPL’s tables below, the defined benefit pension plan amounts represent those respective amounts for their bargaining unit employees covered under the qualified plans that they sponsor, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans. In IPL’s and WPL’s tables below, the OPEB plan amounts represent respective amounts for their employees, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Corporate Services sponsored OPEB plan. Defined Benefit Pension Plans OPEB Plans Three Months Nine Months Three Months Nine Months Alliant Energy 2018 2017 2018 2017 2018 2017 2018 2017 Service cost $3.1 $3.1 $9.1 $9.3 $1.0 $1.2 $3.1 $3.7 Interest cost 11.7 12.7 35.1 38.3 2.0 2.2 5.8 6.5 Expected return on plan assets (17.4 ) (16.3 ) (52.3 ) (49.1 ) (1.5 ) (1.5 ) (4.5 ) (4.6 ) Amortization of prior service credit (0.2 ) (0.1 ) (0.5 ) (0.3 ) — (0.1 ) (0.1 ) (0.2 ) Amortization of actuarial loss 8.8 9.4 26.4 28.2 0.8 1.0 2.5 2.9 Settlement losses (a) — 0.9 — 0.9 — — — — $6.0 $9.7 $17.8 $27.3 $2.3 $2.8 $6.8 $8.3 Defined Benefit Pension Plans OPEB Plans Three Months Nine Months Three Months Nine Months IPL 2018 2017 2018 2017 2018 2017 2018 2017 Service cost $1.8 $1.8 $5.5 $5.5 $0.4 $0.5 $1.3 $1.6 Interest cost 5.3 5.9 16.0 17.6 0.7 0.8 2.3 2.6 Expected return on plan assets (8.1 ) (7.7 ) (24.4 ) (23.1 ) (1.1 ) (1.0 ) (3.3 ) (3.2 ) Amortization of prior service credit — — (0.1 ) (0.1 ) — — — — Amortization of actuarial loss 3.7 4.0 11.2 12.1 0.4 0.5 1.0 1.5 $2.7 $4.0 $8.2 $12.0 $0.4 $0.8 $1.3 $2.5 Defined Benefit Pension Plans OPEB Plans Three Months Nine Months Three Months Nine Months WPL 2018 2017 2018 2017 2018 2017 2018 2017 Service cost $1.1 $1.2 $3.3 $3.6 $0.4 $0.5 $1.2 $1.4 Interest cost 5.0 5.5 15.1 16.4 0.8 0.9 2.3 2.6 Expected return on plan assets (7.6 ) (7.2 ) (22.8 ) (21.4 ) (0.2 ) (0.2 ) (0.5 ) (0.6 ) Amortization of prior service cost (credit) — 0.1 (0.1 ) 0.1 — (0.1 ) (0.1 ) (0.2 ) Amortization of actuarial loss 4.3 4.6 12.9 13.9 0.5 0.4 1.5 1.2 $2.8 $4.2 $8.4 $12.6 $1.5 $1.5 $4.4 $4.4 (a) Settlement losses related to payments made to retired executives of Alliant Energy. NOTE 10(b) Equity-based Compensation Plans - A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three and nine months ended September 30 was as follows (in millions): Alliant Energy IPL WPL Three Months Nine Months Three Months Nine Months Three Months Nine Months 2018 2017 2018 2017 2018 2017 2018 2017 2018 2017 2018 2017 Compensation expense $4.2 $5.1 $12.6 $9.9 $2.4 $2.8 $7.0 $5.4 $1.7 $2.1 $5.1 $4.1 Income tax benefits 1.2 2.1 3.6 4.0 0.7 1.1 2.1 2.2 0.5 0.9 1.4 1.7 As of September 30, 2018 , Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $8.3 million , $4.6 million and $3.5 million , respectively, which is expected to be recognized over a weighted average period of between one and two years. Performance Shares and Performance Units - A summary of the performance shares and performance units activity for the nine months ended September 30 , 2018 , with amounts representing the target number of awards, was as follows: Performance Shares Performance Units Nonvested awards, January 1 223,511 71,737 Granted 74,163 19,840 Vested (90,806 ) (31,910 ) Forfeited (905 ) (1,906 ) Nonvested awards, September 30 205,963 57,761 Vested Awards - During the nine months ended September 30 , 2018 , certain performance shares and performance units that were granted in 2015 vested, resulting in payouts (a combination of cash and common stock for the performance shares and cash only for the performance units) as follows: Performance Shares Performance Units Performance awards vested 90,806 31,910 Percentage of target number of performance awards 137.5 % 137.5 % Aggregate payout value (in millions) $5.3 $1.4 Payout - cash (in millions) $4.9 $1.4 Payout - common stock shares issued 5,078 N/A Fair Value of Awards - At September 28, 2018 , Alliant Energy’s common stock closing price was $42.57 . Additional information related to fair values of nonvested performance shares and performance units at September 30, 2018 , by year of grant, was as follows: Performance Shares Performance Units 2018 Grant 2017 Grant 2016 Grant 2018 Grant 2017 Grant 2016 Grant Nonvested awards at target 73,258 65,350 67,355 19,196 18,062 20,503 Estimated payout percentage based on performance criteria 85 % 105 % 143 % 85 % 105 % 143 % Fair values of each nonvested award $36.18 $44.70 $60.88 $36.18 $44.70 $60.88 Performance Restricted Stock Units - A summary of the performance restricted stock units activity for the nine months ended September 30 , 2018 , with amounts representing the target number of units, was as follows: Units Weighted Average Grant Date Fair Value Nonvested units, January 1 132,705 $36.50 Granted 74,163 38.60 Forfeited (905 ) 38.60 Nonvested units, September 30 205,963 37.25 Restricted Stock Units - A summary of the restricted stock units activity for the nine months ended September 30 , 2018 , was as follows: Nonvested units, January 1 113,749 Granted 63,568 Forfeited (775 ) Nonvested units, September 30 176,542 |
IPL [Member] | |
Benefit Plans | BENEFIT PLANS NOTE 10(a) Pension and Other Postretirement Benefits Plans - Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and nine months ended September 30 are included in the tables below (in millions). The service cost component of net periodic benefit costs is included in “Other operation and maintenance” expenses in the income statements and all other components of net periodic benefit costs are included in “Other (income) and deductions” in the income statements. In IPL’s and WPL’s tables below, the defined benefit pension plan amounts represent those respective amounts for their bargaining unit employees covered under the qualified plans that they sponsor, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans. In IPL’s and WPL’s tables below, the OPEB plan amounts represent respective amounts for their employees, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Corporate Services sponsored OPEB plan. Defined Benefit Pension Plans OPEB Plans Three Months Nine Months Three Months Nine Months Alliant Energy 2018 2017 2018 2017 2018 2017 2018 2017 Service cost $3.1 $3.1 $9.1 $9.3 $1.0 $1.2 $3.1 $3.7 Interest cost 11.7 12.7 35.1 38.3 2.0 2.2 5.8 6.5 Expected return on plan assets (17.4 ) (16.3 ) (52.3 ) (49.1 ) (1.5 ) (1.5 ) (4.5 ) (4.6 ) Amortization of prior service credit (0.2 ) (0.1 ) (0.5 ) (0.3 ) — (0.1 ) (0.1 ) (0.2 ) Amortization of actuarial loss 8.8 9.4 26.4 28.2 0.8 1.0 2.5 2.9 Settlement losses (a) — 0.9 — 0.9 — — — — $6.0 $9.7 $17.8 $27.3 $2.3 $2.8 $6.8 $8.3 Defined Benefit Pension Plans OPEB Plans Three Months Nine Months Three Months Nine Months IPL 2018 2017 2018 2017 2018 2017 2018 2017 Service cost $1.8 $1.8 $5.5 $5.5 $0.4 $0.5 $1.3 $1.6 Interest cost 5.3 5.9 16.0 17.6 0.7 0.8 2.3 2.6 Expected return on plan assets (8.1 ) (7.7 ) (24.4 ) (23.1 ) (1.1 ) (1.0 ) (3.3 ) (3.2 ) Amortization of prior service credit — — (0.1 ) (0.1 ) — — — — Amortization of actuarial loss 3.7 4.0 11.2 12.1 0.4 0.5 1.0 1.5 $2.7 $4.0 $8.2 $12.0 $0.4 $0.8 $1.3 $2.5 Defined Benefit Pension Plans OPEB Plans Three Months Nine Months Three Months Nine Months WPL 2018 2017 2018 2017 2018 2017 2018 2017 Service cost $1.1 $1.2 $3.3 $3.6 $0.4 $0.5 $1.2 $1.4 Interest cost 5.0 5.5 15.1 16.4 0.8 0.9 2.3 2.6 Expected return on plan assets (7.6 ) (7.2 ) (22.8 ) (21.4 ) (0.2 ) (0.2 ) (0.5 ) (0.6 ) Amortization of prior service cost (credit) — 0.1 (0.1 ) 0.1 — (0.1 ) (0.1 ) (0.2 ) Amortization of actuarial loss 4.3 4.6 12.9 13.9 0.5 0.4 1.5 1.2 $2.8 $4.2 $8.4 $12.6 $1.5 $1.5 $4.4 $4.4 (a) Settlement losses related to payments made to retired executives of Alliant Energy. NOTE 10(b) Equity-based Compensation Plans - A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three and nine months ended September 30 was as follows (in millions): Alliant Energy IPL WPL Three Months Nine Months Three Months Nine Months Three Months Nine Months 2018 2017 2018 2017 2018 2017 2018 2017 2018 2017 2018 2017 Compensation expense $4.2 $5.1 $12.6 $9.9 $2.4 $2.8 $7.0 $5.4 $1.7 $2.1 $5.1 $4.1 Income tax benefits 1.2 2.1 3.6 4.0 0.7 1.1 2.1 2.2 0.5 0.9 1.4 1.7 As of September 30, 2018 , Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $8.3 million , $4.6 million and $3.5 million , respectively, which is expected to be recognized over a weighted average period of between one and two years. Performance Shares and Performance Units - A summary of the performance shares and performance units activity for the nine months ended September 30 , 2018 , with amounts representing the target number of awards, was as follows: Performance Shares Performance Units Nonvested awards, January 1 223,511 71,737 Granted 74,163 19,840 Vested (90,806 ) (31,910 ) Forfeited (905 ) (1,906 ) Nonvested awards, September 30 205,963 57,761 Vested Awards - During the nine months ended September 30 , 2018 , certain performance shares and performance units that were granted in 2015 vested, resulting in payouts (a combination of cash and common stock for the performance shares and cash only for the performance units) as follows: Performance Shares Performance Units Performance awards vested 90,806 31,910 Percentage of target number of performance awards 137.5 % 137.5 % Aggregate payout value (in millions) $5.3 $1.4 Payout - cash (in millions) $4.9 $1.4 Payout - common stock shares issued 5,078 N/A Fair Value of Awards - At September 28, 2018 , Alliant Energy’s common stock closing price was $42.57 . Additional information related to fair values of nonvested performance shares and performance units at September 30, 2018 , by year of grant, was as follows: Performance Shares Performance Units 2018 Grant 2017 Grant 2016 Grant 2018 Grant 2017 Grant 2016 Grant Nonvested awards at target 73,258 65,350 67,355 19,196 18,062 20,503 Estimated payout percentage based on performance criteria 85 % 105 % 143 % 85 % 105 % 143 % Fair values of each nonvested award $36.18 $44.70 $60.88 $36.18 $44.70 $60.88 Performance Restricted Stock Units - A summary of the performance restricted stock units activity for the nine months ended September 30 , 2018 , with amounts representing the target number of units, was as follows: Units Weighted Average Grant Date Fair Value Nonvested units, January 1 132,705 $36.50 Granted 74,163 38.60 Forfeited (905 ) 38.60 Nonvested units, September 30 205,963 37.25 Restricted Stock Units - A summary of the restricted stock units activity for the nine months ended September 30 , 2018 , was as follows: Nonvested units, January 1 113,749 Granted 63,568 Forfeited (775 ) Nonvested units, September 30 176,542 |
WPL [Member] | |
Benefit Plans | BENEFIT PLANS NOTE 10(a) Pension and Other Postretirement Benefits Plans - Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and nine months ended September 30 are included in the tables below (in millions). The service cost component of net periodic benefit costs is included in “Other operation and maintenance” expenses in the income statements and all other components of net periodic benefit costs are included in “Other (income) and deductions” in the income statements. In IPL’s and WPL’s tables below, the defined benefit pension plan amounts represent those respective amounts for their bargaining unit employees covered under the qualified plans that they sponsor, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans. In IPL’s and WPL’s tables below, the OPEB plan amounts represent respective amounts for their employees, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Corporate Services sponsored OPEB plan. Defined Benefit Pension Plans OPEB Plans Three Months Nine Months Three Months Nine Months Alliant Energy 2018 2017 2018 2017 2018 2017 2018 2017 Service cost $3.1 $3.1 $9.1 $9.3 $1.0 $1.2 $3.1 $3.7 Interest cost 11.7 12.7 35.1 38.3 2.0 2.2 5.8 6.5 Expected return on plan assets (17.4 ) (16.3 ) (52.3 ) (49.1 ) (1.5 ) (1.5 ) (4.5 ) (4.6 ) Amortization of prior service credit (0.2 ) (0.1 ) (0.5 ) (0.3 ) — (0.1 ) (0.1 ) (0.2 ) Amortization of actuarial loss 8.8 9.4 26.4 28.2 0.8 1.0 2.5 2.9 Settlement losses (a) — 0.9 — 0.9 — — — — $6.0 $9.7 $17.8 $27.3 $2.3 $2.8 $6.8 $8.3 Defined Benefit Pension Plans OPEB Plans Three Months Nine Months Three Months Nine Months IPL 2018 2017 2018 2017 2018 2017 2018 2017 Service cost $1.8 $1.8 $5.5 $5.5 $0.4 $0.5 $1.3 $1.6 Interest cost 5.3 5.9 16.0 17.6 0.7 0.8 2.3 2.6 Expected return on plan assets (8.1 ) (7.7 ) (24.4 ) (23.1 ) (1.1 ) (1.0 ) (3.3 ) (3.2 ) Amortization of prior service credit — — (0.1 ) (0.1 ) — — — — Amortization of actuarial loss 3.7 4.0 11.2 12.1 0.4 0.5 1.0 1.5 $2.7 $4.0 $8.2 $12.0 $0.4 $0.8 $1.3 $2.5 Defined Benefit Pension Plans OPEB Plans Three Months Nine Months Three Months Nine Months WPL 2018 2017 2018 2017 2018 2017 2018 2017 Service cost $1.1 $1.2 $3.3 $3.6 $0.4 $0.5 $1.2 $1.4 Interest cost 5.0 5.5 15.1 16.4 0.8 0.9 2.3 2.6 Expected return on plan assets (7.6 ) (7.2 ) (22.8 ) (21.4 ) (0.2 ) (0.2 ) (0.5 ) (0.6 ) Amortization of prior service cost (credit) — 0.1 (0.1 ) 0.1 — (0.1 ) (0.1 ) (0.2 ) Amortization of actuarial loss 4.3 4.6 12.9 13.9 0.5 0.4 1.5 1.2 $2.8 $4.2 $8.4 $12.6 $1.5 $1.5 $4.4 $4.4 (a) Settlement losses related to payments made to retired executives of Alliant Energy. NOTE 10(b) Equity-based Compensation Plans - A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three and nine months ended September 30 was as follows (in millions): Alliant Energy IPL WPL Three Months Nine Months Three Months Nine Months Three Months Nine Months 2018 2017 2018 2017 2018 2017 2018 2017 2018 2017 2018 2017 Compensation expense $4.2 $5.1 $12.6 $9.9 $2.4 $2.8 $7.0 $5.4 $1.7 $2.1 $5.1 $4.1 Income tax benefits 1.2 2.1 3.6 4.0 0.7 1.1 2.1 2.2 0.5 0.9 1.4 1.7 As of September 30, 2018 , Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $8.3 million , $4.6 million and $3.5 million , respectively, which is expected to be recognized over a weighted average period of between one and two years. Performance Shares and Performance Units - A summary of the performance shares and performance units activity for the nine months ended September 30 , 2018 , with amounts representing the target number of awards, was as follows: Performance Shares Performance Units Nonvested awards, January 1 223,511 71,737 Granted 74,163 19,840 Vested (90,806 ) (31,910 ) Forfeited (905 ) (1,906 ) Nonvested awards, September 30 205,963 57,761 Vested Awards - During the nine months ended September 30 , 2018 , certain performance shares and performance units that were granted in 2015 vested, resulting in payouts (a combination of cash and common stock for the performance shares and cash only for the performance units) as follows: Performance Shares Performance Units Performance awards vested 90,806 31,910 Percentage of target number of performance awards 137.5 % 137.5 % Aggregate payout value (in millions) $5.3 $1.4 Payout - cash (in millions) $4.9 $1.4 Payout - common stock shares issued 5,078 N/A Fair Value of Awards - At September 28, 2018 , Alliant Energy’s common stock closing price was $42.57 . Additional information related to fair values of nonvested performance shares and performance units at September 30, 2018 , by year of grant, was as follows: Performance Shares Performance Units 2018 Grant 2017 Grant 2016 Grant 2018 Grant 2017 Grant 2016 Grant Nonvested awards at target 73,258 65,350 67,355 19,196 18,062 20,503 Estimated payout percentage based on performance criteria 85 % 105 % 143 % 85 % 105 % 143 % Fair values of each nonvested award $36.18 $44.70 $60.88 $36.18 $44.70 $60.88 Performance Restricted Stock Units - A summary of the performance restricted stock units activity for the nine months ended September 30 , 2018 , with amounts representing the target number of units, was as follows: Units Weighted Average Grant Date Fair Value Nonvested units, January 1 132,705 $36.50 Granted 74,163 38.60 Forfeited (905 ) 38.60 Nonvested units, September 30 205,963 37.25 Restricted Stock Units - A summary of the restricted stock units activity for the nine months ended September 30 , 2018 , was as follows: Nonvested units, January 1 113,749 Granted 63,568 Forfeited (775 ) Nonvested units, September 30 176,542 |
Fair Value Measurements
Fair Value Measurements | 9 Months Ended |
Sep. 30, 2018 | |
Fair Value Measurements | FAIR VALUE MEASUREMENTS Fair Value of Financial Instruments - The carrying amounts of current assets and current liabilities approximate fair value because of the short maturity of such financial instruments. At September 30, 2018, money market fund investments were measured at fair value using quoted market prices on listed exchanges. Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions): Alliant Energy September 30, 2018 December 31, 2017 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $228.0 $228.0 $— $— $228.0 $— $— $— $— $— Derivatives 48.0 — 16.5 31.5 48.0 25.1 — 4.1 21.0 25.1 Deferred proceeds 243.7 — — 243.7 243.7 222.1 — — 222.1 222.1 Liabilities and equity: Derivatives 22.0 — 14.7 7.3 22.0 41.7 — 8.5 33.2 41.7 Long-term debt (incl. current maturities) 5,754.3 — 6,057.8 2.5 6,060.3 4,866.3 — 5,444.6 2.9 5,447.5 Cumulative preferred stock of IPL 200.0 200.0 — — 200.0 200.0 203.8 — — 203.8 IPL September 30, 2018 December 31, 2017 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $228.0 $228.0 $— $— $228.0 $— $— $— $— $— Derivatives 29.1 — 6.7 22.4 29.1 17.1 — 2.0 15.1 17.1 Deferred proceeds 243.7 — — 243.7 243.7 222.1 — — 222.1 222.1 Liabilities and equity: Derivatives 9.7 — 5.5 4.2 9.7 19.4 — 2.9 16.5 19.4 Long-term debt (incl. current maturities) 2,801.8 — 2,916.2 — 2,916.2 2,406.0 — 2,665.7 — 2,665.7 Cumulative preferred stock 200.0 200.0 — — 200.0 200.0 203.8 — — 203.8 WPL September 30, 2018 December 31, 2017 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Derivatives $18.9 $— $9.8 $9.1 $18.9 $8.0 $— $2.1 $5.9 $8.0 Liabilities: Derivatives 12.3 — 9.2 3.1 12.3 22.3 — 5.6 16.7 22.3 Long-term debt (incl. current maturities) 1,834.5 — 2,020.9 — 2,020.9 1,833.4 — 2,147.9 — 2,147.9 Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions): Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended September 30 2018 2017 2018 2017 Beginning balance, July 1 ($10.7 ) $9.2 $208.3 $170.0 Total net gains (losses) included in changes in net assets (realized/unrealized) 25.7 (4.3 ) — — Transfers out of Level 3 15.6 — — — Sales (0.2 ) (0.1 ) — — Settlements (a) (6.2 ) (8.5 ) 35.4 (54.7 ) Ending balance, September 30 $24.2 ($3.7 ) $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $26.1 ($4.2 ) $— $— Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Nine Months Ended September 30 2018 2017 2018 2017 Beginning balance, January 1 ($12.2 ) $8.7 $222.1 $211.1 Total net gains (losses) included in changes in net assets (realized/unrealized) 15.7 (31.3 ) — — Transfers out of Level 3 15.6 12.2 — — Purchases 26.7 28.3 — — Sales (0.2 ) (0.3 ) — — Settlements (a) (21.4 ) (21.3 ) 21.6 (95.8 ) Ending balance, September 30 $24.2 ($3.7 ) $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $16.5 ($29.4 ) $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended September 30 2018 2017 2018 2017 Beginning balance, July 1 ($4.1 ) $17.1 $208.3 $170.0 Total net gains (losses) included in changes in net assets (realized/unrealized) 16.8 (4.4 ) — — Transfers out of Level 3 10.5 — — — Sales (0.1 ) (0.1 ) — — Settlements (a) (4.9 ) (7.3 ) 35.4 (54.7 ) Ending balance, September 30 $18.2 $5.3 $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $16.8 ($4.5 ) $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Nine Months Ended September 30 2018 2017 2018 2017 Beginning balance, January 1 ($1.4 ) $10.1 $222.1 $211.1 Total net gains (losses) included in changes in net assets (realized/unrealized) 7.6 (13.9 ) — — Transfers out of Level 3 10.5 3.1 — — Purchases 19.3 24.6 — — Sales (0.1 ) (0.2 ) — — Settlements (a) (17.7 ) (18.4 ) 21.6 (95.8 ) Ending balance, September 30 $18.2 $5.3 $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $7.9 ($12.6 ) $— $— WPL Commodity Contract Derivative Assets and (Liabilities), net Three Months Ended September 30 2018 2017 Beginning balance, July 1 ($6.6 ) ($7.9 ) Total net gains included in changes in net assets (realized/unrealized) 8.9 0.1 Transfers out of Level 3 5.1 — Sales (0.1 ) — Settlements (1.3 ) (1.2 ) Ending balance, September 30 $6.0 ($9.0 ) The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at September 30 $9.3 $0.3 WPL Commodity Contract Derivative Assets and (Liabilities), net Nine Months Ended September 30 2018 2017 Beginning balance, January 1 ($10.8 ) ($1.4 ) Total net gains (losses) included in changes in net assets (realized/unrealized) 8.1 (17.4 ) Transfers out of Level 3 5.1 9.1 Purchases 7.4 3.7 Sales (0.1 ) (0.1 ) Settlements (3.7 ) (2.9 ) Ending balance, September 30 $6.0 ($9.0 ) The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $8.6 ($16.8 ) (a) Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for doubtful accounts associated with the receivables sold and cash amounts received from the receivables sold. Commodity Contracts - The fair value of electric, natural gas, coal and diesel fuel commodity contracts categorized as Level 3 was recognized as net derivative assets (liabilities) as follows (in millions): Alliant Energy IPL WPL Excluding FTRs FTRs Excluding FTRs FTRs Excluding FTRs FTRs September 30, 2018 $7.9 $16.3 $5.4 $12.8 $2.5 $3.5 December 31, 2017 (23.5 ) 11.3 (11.5 ) 10.1 (12.0 ) 1.2 |
IPL [Member] | |
Fair Value Measurements | FAIR VALUE MEASUREMENTS Fair Value of Financial Instruments - The carrying amounts of current assets and current liabilities approximate fair value because of the short maturity of such financial instruments. At September 30, 2018, money market fund investments were measured at fair value using quoted market prices on listed exchanges. Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions): Alliant Energy September 30, 2018 December 31, 2017 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $228.0 $228.0 $— $— $228.0 $— $— $— $— $— Derivatives 48.0 — 16.5 31.5 48.0 25.1 — 4.1 21.0 25.1 Deferred proceeds 243.7 — — 243.7 243.7 222.1 — — 222.1 222.1 Liabilities and equity: Derivatives 22.0 — 14.7 7.3 22.0 41.7 — 8.5 33.2 41.7 Long-term debt (incl. current maturities) 5,754.3 — 6,057.8 2.5 6,060.3 4,866.3 — 5,444.6 2.9 5,447.5 Cumulative preferred stock of IPL 200.0 200.0 — — 200.0 200.0 203.8 — — 203.8 IPL September 30, 2018 December 31, 2017 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $228.0 $228.0 $— $— $228.0 $— $— $— $— $— Derivatives 29.1 — 6.7 22.4 29.1 17.1 — 2.0 15.1 17.1 Deferred proceeds 243.7 — — 243.7 243.7 222.1 — — 222.1 222.1 Liabilities and equity: Derivatives 9.7 — 5.5 4.2 9.7 19.4 — 2.9 16.5 19.4 Long-term debt (incl. current maturities) 2,801.8 — 2,916.2 — 2,916.2 2,406.0 — 2,665.7 — 2,665.7 Cumulative preferred stock 200.0 200.0 — — 200.0 200.0 203.8 — — 203.8 WPL September 30, 2018 December 31, 2017 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Derivatives $18.9 $— $9.8 $9.1 $18.9 $8.0 $— $2.1 $5.9 $8.0 Liabilities: Derivatives 12.3 — 9.2 3.1 12.3 22.3 — 5.6 16.7 22.3 Long-term debt (incl. current maturities) 1,834.5 — 2,020.9 — 2,020.9 1,833.4 — 2,147.9 — 2,147.9 Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions): Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended September 30 2018 2017 2018 2017 Beginning balance, July 1 ($10.7 ) $9.2 $208.3 $170.0 Total net gains (losses) included in changes in net assets (realized/unrealized) 25.7 (4.3 ) — — Transfers out of Level 3 15.6 — — — Sales (0.2 ) (0.1 ) — — Settlements (a) (6.2 ) (8.5 ) 35.4 (54.7 ) Ending balance, September 30 $24.2 ($3.7 ) $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $26.1 ($4.2 ) $— $— Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Nine Months Ended September 30 2018 2017 2018 2017 Beginning balance, January 1 ($12.2 ) $8.7 $222.1 $211.1 Total net gains (losses) included in changes in net assets (realized/unrealized) 15.7 (31.3 ) — — Transfers out of Level 3 15.6 12.2 — — Purchases 26.7 28.3 — — Sales (0.2 ) (0.3 ) — — Settlements (a) (21.4 ) (21.3 ) 21.6 (95.8 ) Ending balance, September 30 $24.2 ($3.7 ) $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $16.5 ($29.4 ) $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended September 30 2018 2017 2018 2017 Beginning balance, July 1 ($4.1 ) $17.1 $208.3 $170.0 Total net gains (losses) included in changes in net assets (realized/unrealized) 16.8 (4.4 ) — — Transfers out of Level 3 10.5 — — — Sales (0.1 ) (0.1 ) — — Settlements (a) (4.9 ) (7.3 ) 35.4 (54.7 ) Ending balance, September 30 $18.2 $5.3 $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $16.8 ($4.5 ) $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Nine Months Ended September 30 2018 2017 2018 2017 Beginning balance, January 1 ($1.4 ) $10.1 $222.1 $211.1 Total net gains (losses) included in changes in net assets (realized/unrealized) 7.6 (13.9 ) — — Transfers out of Level 3 10.5 3.1 — — Purchases 19.3 24.6 — — Sales (0.1 ) (0.2 ) — — Settlements (a) (17.7 ) (18.4 ) 21.6 (95.8 ) Ending balance, September 30 $18.2 $5.3 $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $7.9 ($12.6 ) $— $— WPL Commodity Contract Derivative Assets and (Liabilities), net Three Months Ended September 30 2018 2017 Beginning balance, July 1 ($6.6 ) ($7.9 ) Total net gains included in changes in net assets (realized/unrealized) 8.9 0.1 Transfers out of Level 3 5.1 — Sales (0.1 ) — Settlements (1.3 ) (1.2 ) Ending balance, September 30 $6.0 ($9.0 ) The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at September 30 $9.3 $0.3 WPL Commodity Contract Derivative Assets and (Liabilities), net Nine Months Ended September 30 2018 2017 Beginning balance, January 1 ($10.8 ) ($1.4 ) Total net gains (losses) included in changes in net assets (realized/unrealized) 8.1 (17.4 ) Transfers out of Level 3 5.1 9.1 Purchases 7.4 3.7 Sales (0.1 ) (0.1 ) Settlements (3.7 ) (2.9 ) Ending balance, September 30 $6.0 ($9.0 ) The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $8.6 ($16.8 ) (a) Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for doubtful accounts associated with the receivables sold and cash amounts received from the receivables sold. Commodity Contracts - The fair value of electric, natural gas, coal and diesel fuel commodity contracts categorized as Level 3 was recognized as net derivative assets (liabilities) as follows (in millions): Alliant Energy IPL WPL Excluding FTRs FTRs Excluding FTRs FTRs Excluding FTRs FTRs September 30, 2018 $7.9 $16.3 $5.4 $12.8 $2.5 $3.5 December 31, 2017 (23.5 ) 11.3 (11.5 ) 10.1 (12.0 ) 1.2 |
WPL [Member] | |
Fair Value Measurements | FAIR VALUE MEASUREMENTS Fair Value of Financial Instruments - The carrying amounts of current assets and current liabilities approximate fair value because of the short maturity of such financial instruments. At September 30, 2018, money market fund investments were measured at fair value using quoted market prices on listed exchanges. Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions): Alliant Energy September 30, 2018 December 31, 2017 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $228.0 $228.0 $— $— $228.0 $— $— $— $— $— Derivatives 48.0 — 16.5 31.5 48.0 25.1 — 4.1 21.0 25.1 Deferred proceeds 243.7 — — 243.7 243.7 222.1 — — 222.1 222.1 Liabilities and equity: Derivatives 22.0 — 14.7 7.3 22.0 41.7 — 8.5 33.2 41.7 Long-term debt (incl. current maturities) 5,754.3 — 6,057.8 2.5 6,060.3 4,866.3 — 5,444.6 2.9 5,447.5 Cumulative preferred stock of IPL 200.0 200.0 — — 200.0 200.0 203.8 — — 203.8 IPL September 30, 2018 December 31, 2017 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $228.0 $228.0 $— $— $228.0 $— $— $— $— $— Derivatives 29.1 — 6.7 22.4 29.1 17.1 — 2.0 15.1 17.1 Deferred proceeds 243.7 — — 243.7 243.7 222.1 — — 222.1 222.1 Liabilities and equity: Derivatives 9.7 — 5.5 4.2 9.7 19.4 — 2.9 16.5 19.4 Long-term debt (incl. current maturities) 2,801.8 — 2,916.2 — 2,916.2 2,406.0 — 2,665.7 — 2,665.7 Cumulative preferred stock 200.0 200.0 — — 200.0 200.0 203.8 — — 203.8 WPL September 30, 2018 December 31, 2017 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Derivatives $18.9 $— $9.8 $9.1 $18.9 $8.0 $— $2.1 $5.9 $8.0 Liabilities: Derivatives 12.3 — 9.2 3.1 12.3 22.3 — 5.6 16.7 22.3 Long-term debt (incl. current maturities) 1,834.5 — 2,020.9 — 2,020.9 1,833.4 — 2,147.9 — 2,147.9 Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions): Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended September 30 2018 2017 2018 2017 Beginning balance, July 1 ($10.7 ) $9.2 $208.3 $170.0 Total net gains (losses) included in changes in net assets (realized/unrealized) 25.7 (4.3 ) — — Transfers out of Level 3 15.6 — — — Sales (0.2 ) (0.1 ) — — Settlements (a) (6.2 ) (8.5 ) 35.4 (54.7 ) Ending balance, September 30 $24.2 ($3.7 ) $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $26.1 ($4.2 ) $— $— Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Nine Months Ended September 30 2018 2017 2018 2017 Beginning balance, January 1 ($12.2 ) $8.7 $222.1 $211.1 Total net gains (losses) included in changes in net assets (realized/unrealized) 15.7 (31.3 ) — — Transfers out of Level 3 15.6 12.2 — — Purchases 26.7 28.3 — — Sales (0.2 ) (0.3 ) — — Settlements (a) (21.4 ) (21.3 ) 21.6 (95.8 ) Ending balance, September 30 $24.2 ($3.7 ) $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $16.5 ($29.4 ) $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended September 30 2018 2017 2018 2017 Beginning balance, July 1 ($4.1 ) $17.1 $208.3 $170.0 Total net gains (losses) included in changes in net assets (realized/unrealized) 16.8 (4.4 ) — — Transfers out of Level 3 10.5 — — — Sales (0.1 ) (0.1 ) — — Settlements (a) (4.9 ) (7.3 ) 35.4 (54.7 ) Ending balance, September 30 $18.2 $5.3 $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $16.8 ($4.5 ) $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Nine Months Ended September 30 2018 2017 2018 2017 Beginning balance, January 1 ($1.4 ) $10.1 $222.1 $211.1 Total net gains (losses) included in changes in net assets (realized/unrealized) 7.6 (13.9 ) — — Transfers out of Level 3 10.5 3.1 — — Purchases 19.3 24.6 — — Sales (0.1 ) (0.2 ) — — Settlements (a) (17.7 ) (18.4 ) 21.6 (95.8 ) Ending balance, September 30 $18.2 $5.3 $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $7.9 ($12.6 ) $— $— WPL Commodity Contract Derivative Assets and (Liabilities), net Three Months Ended September 30 2018 2017 Beginning balance, July 1 ($6.6 ) ($7.9 ) Total net gains included in changes in net assets (realized/unrealized) 8.9 0.1 Transfers out of Level 3 5.1 — Sales (0.1 ) — Settlements (1.3 ) (1.2 ) Ending balance, September 30 $6.0 ($9.0 ) The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at September 30 $9.3 $0.3 WPL Commodity Contract Derivative Assets and (Liabilities), net Nine Months Ended September 30 2018 2017 Beginning balance, January 1 ($10.8 ) ($1.4 ) Total net gains (losses) included in changes in net assets (realized/unrealized) 8.1 (17.4 ) Transfers out of Level 3 5.1 9.1 Purchases 7.4 3.7 Sales (0.1 ) (0.1 ) Settlements (3.7 ) (2.9 ) Ending balance, September 30 $6.0 ($9.0 ) The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $8.6 ($16.8 ) (a) Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for doubtful accounts associated with the receivables sold and cash amounts received from the receivables sold. Commodity Contracts - The fair value of electric, natural gas, coal and diesel fuel commodity contracts categorized as Level 3 was recognized as net derivative assets (liabilities) as follows (in millions): Alliant Energy IPL WPL Excluding FTRs FTRs Excluding FTRs FTRs Excluding FTRs FTRs September 30, 2018 $7.9 $16.3 $5.4 $12.8 $2.5 $3.5 December 31, 2017 (23.5 ) 11.3 (11.5 ) 10.1 (12.0 ) 1.2 |
Derivative Instruments
Derivative Instruments | 9 Months Ended |
Sep. 30, 2018 | |
Derivative Instruments [Line Items] | |
Derivative Instruments | DERIVATIVE INSTRUMENTS Commodity Derivatives - Notional Amounts - As of September 30, 2018 , gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands): Electricity FTRs Natural Gas Coal Diesel Fuel MWhs Years MWhs Years Dths Years Tons Years Gallons Years Alliant Energy 331 2018 16,553 2018-2019 179,275 2018-2026 11,922 2018-2021 3,906 2018-2019 IPL — — 9,220 2018-2019 83,485 2018-2026 4,849 2018-2021 — — WPL 331 2018 7,333 2018-2019 95,790 2018-2026 7,073 2018-2021 3,906 2018-2019 Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities. The fair values of current derivative assets are included in “Other current assets,” non-current derivative assets are included in “Deferred charges and other,” current derivative liabilities are included in “Other current liabilities” and non-current derivative liabilities are included in “Other liabilities” on the balance sheets as follows (in millions): Alliant Energy IPL WPL September 30, December 31, September 30, December 31, September 30, December 31, Current derivative assets $39.7 $21.1 $26.2 $15.8 $13.5 $5.3 Non-current derivative assets 8.3 4.0 2.9 1.3 5.4 2.7 Current derivative liabilities 7.2 18.7 3.2 5.0 4.0 13.7 Non-current derivative liabilities 14.8 23.0 6.5 14.4 8.3 8.6 Credit Risk-related Contingent Features - Various agreements contain credit risk-related contingent features, including requirements to maintain certain credit ratings and/or limitations on liability positions under the agreements based on credit ratings. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. In the event of a material change in creditworthiness or if liability positions exceed certain contractual limits, credit support may need to be provided in the form of letters of credit or cash collateral up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At September 30, 2018 and December 31, 2017 , the aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position was not materially different than amounts that would be required to be posted as credit support to counterparties by Alliant Energy, IPL or WPL if the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered. Balance Sheet Offsetting - The fair value amounts of derivative instruments subject to a master netting arrangement are not netted by counterparty on the balance sheets. However, if the fair value amounts of derivative instruments by counterparty were netted, amounts would not be materially different from gross amounts of derivative assets and derivative liabilities at September 30, 2018 and December 31, 2017 . Fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) are not offset against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement. |
IPL [Member] | |
Derivative Instruments [Line Items] | |
Derivative Instruments | DERIVATIVE INSTRUMENTS Commodity Derivatives - Notional Amounts - As of September 30, 2018 , gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands): Electricity FTRs Natural Gas Coal Diesel Fuel MWhs Years MWhs Years Dths Years Tons Years Gallons Years Alliant Energy 331 2018 16,553 2018-2019 179,275 2018-2026 11,922 2018-2021 3,906 2018-2019 IPL — — 9,220 2018-2019 83,485 2018-2026 4,849 2018-2021 — — WPL 331 2018 7,333 2018-2019 95,790 2018-2026 7,073 2018-2021 3,906 2018-2019 Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities. The fair values of current derivative assets are included in “Other current assets,” non-current derivative assets are included in “Deferred charges and other,” current derivative liabilities are included in “Other current liabilities” and non-current derivative liabilities are included in “Other liabilities” on the balance sheets as follows (in millions): Alliant Energy IPL WPL September 30, December 31, September 30, December 31, September 30, December 31, Current derivative assets $39.7 $21.1 $26.2 $15.8 $13.5 $5.3 Non-current derivative assets 8.3 4.0 2.9 1.3 5.4 2.7 Current derivative liabilities 7.2 18.7 3.2 5.0 4.0 13.7 Non-current derivative liabilities 14.8 23.0 6.5 14.4 8.3 8.6 Credit Risk-related Contingent Features - Various agreements contain credit risk-related contingent features, including requirements to maintain certain credit ratings and/or limitations on liability positions under the agreements based on credit ratings. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. In the event of a material change in creditworthiness or if liability positions exceed certain contractual limits, credit support may need to be provided in the form of letters of credit or cash collateral up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At September 30, 2018 and December 31, 2017 , the aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position was not materially different than amounts that would be required to be posted as credit support to counterparties by Alliant Energy, IPL or WPL if the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered. Balance Sheet Offsetting - The fair value amounts of derivative instruments subject to a master netting arrangement are not netted by counterparty on the balance sheets. However, if the fair value amounts of derivative instruments by counterparty were netted, amounts would not be materially different from gross amounts of derivative assets and derivative liabilities at September 30, 2018 and December 31, 2017 . Fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) are not offset against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement. |
WPL [Member] | |
Derivative Instruments [Line Items] | |
Derivative Instruments | DERIVATIVE INSTRUMENTS Commodity Derivatives - Notional Amounts - As of September 30, 2018 , gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands): Electricity FTRs Natural Gas Coal Diesel Fuel MWhs Years MWhs Years Dths Years Tons Years Gallons Years Alliant Energy 331 2018 16,553 2018-2019 179,275 2018-2026 11,922 2018-2021 3,906 2018-2019 IPL — — 9,220 2018-2019 83,485 2018-2026 4,849 2018-2021 — — WPL 331 2018 7,333 2018-2019 95,790 2018-2026 7,073 2018-2021 3,906 2018-2019 Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities. The fair values of current derivative assets are included in “Other current assets,” non-current derivative assets are included in “Deferred charges and other,” current derivative liabilities are included in “Other current liabilities” and non-current derivative liabilities are included in “Other liabilities” on the balance sheets as follows (in millions): Alliant Energy IPL WPL September 30, December 31, September 30, December 31, September 30, December 31, Current derivative assets $39.7 $21.1 $26.2 $15.8 $13.5 $5.3 Non-current derivative assets 8.3 4.0 2.9 1.3 5.4 2.7 Current derivative liabilities 7.2 18.7 3.2 5.0 4.0 13.7 Non-current derivative liabilities 14.8 23.0 6.5 14.4 8.3 8.6 Credit Risk-related Contingent Features - Various agreements contain credit risk-related contingent features, including requirements to maintain certain credit ratings and/or limitations on liability positions under the agreements based on credit ratings. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. In the event of a material change in creditworthiness or if liability positions exceed certain contractual limits, credit support may need to be provided in the form of letters of credit or cash collateral up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At September 30, 2018 and December 31, 2017 , the aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position was not materially different than amounts that would be required to be posted as credit support to counterparties by Alliant Energy, IPL or WPL if the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered. Balance Sheet Offsetting - The fair value amounts of derivative instruments subject to a master netting arrangement are not netted by counterparty on the balance sheets. However, if the fair value amounts of derivative instruments by counterparty were netted, amounts would not be materially different from gross amounts of derivative assets and derivative liabilities at September 30, 2018 and December 31, 2017 . Fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) are not offset against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement. |
Commitments And Contingencies
Commitments And Contingencies | 9 Months Ended |
Sep. 30, 2018 | |
Commitments and Contingencies Disclosure | COMMITMENTS AND CONTINGENCIES NOTE 13(a) Capital Purchase Obligations - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects. IPL’s projects include the expansion of wind generation and installation of an SCR system at Ottumwa Unit 1 to reduce NOx emissions at the EGU. WPL’s projects include West Riverside. At September 30, 2018 , Alliant Energy’s, IPL’s and WPL’s minimum future commitments related to certain contractual obligations for these projects were $82 million , $26 million and $56 million , respectively. NOTE 13(b) Other Purchase Obligations - Various commodity supply, transportation and storage contracts help meet obligations to provide electricity and natural gas to utility customers. In addition, there are various purchase obligations associated with other goods and services. At September 30, 2018 , minimum future commitments related to these purchase obligations were as follows (in millions): Alliant Energy IPL WPL Purchased power (a) $1,089 $1,063 $26 Natural gas 921 394 527 Coal (b) 169 84 85 Other (c) 43 24 5 $2,222 $1,565 $643 (a) Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased. Alliant Energy’s and IPL’s amounts include minimum future commitments related to IPL’s purchase of capacity and the resulting energy from DAEC through December 2025. In July 2018, IPL entered into an amendment to shorten the term of the DAEC PPA by five years in exchange for a $110 million buyout payment by IPL in September 2020, which is not included in Alliant Energy’s and IPL’s amounts. The amendment to the DAEC PPA is contingent upon IUB approval of IPL’s July 2018 application regarding recovery of the buyout payment. (b) Corporate Services entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. These commitments were assigned to IPL and WPL based on information available as of September 30, 2018 regarding expected future usage, which is subject to change. (c) Includes individual commitments incurred during the normal course of business that exceeded $1 million at September 30, 2018 . NOTE 13(c) Guarantees and Indemnifications - Whiting Petroleum - In 2004, Alliant Energy sold its remaining interest in Whiting Petroleum. Whiting Petroleum is an independent oil and gas company. Alliant Energy Resources, LLC, as the successor to a predecessor entity that owned Whiting Petroleum, and a wholly-owned subsidiary of AEF, continues to guarantee the partnership obligations of an affiliate of Whiting Petroleum under general partnership agreements in the oil and gas industry, including with respect to the future abandonment of certain platforms off the coast of California and related onshore plant and equipment owned by the partnerships. The guarantees do not include a maximum limit. As of September 30, 2018 , the present value of the abandonment obligations is estimated at $36 million . Alliant Energy is not aware of any material liabilities related to these guarantees of which it is probable that Alliant Energy Resources, LLC will be obligated to pay and therefore has not recognized any material liabilities related to this guarantee as of September 30, 2018 . Non-utility Wind Farm in Oklahoma - In July 2017, a wholly-owned subsidiary of AEF acquired a cash equity ownership interest in a non-utility wind farm located in Oklahoma. The wind farm provides electricity to a third-party under a long-term PPA. Alliant Energy provided a parent guarantee of its subsidiary’s indemnification obligations under the related operating agreement and PPA. Alliant Energy’s obligations under the operating agreement were $90 million as of September 30, 2018 and will reduce annually until expiring in July 2047 . Alliant Energy’s obligations under the PPA are subject to a maximum limit of $17 million and expire in December 2031 , subject to potential extension. Alliant Energy is not aware of any material liabilities related to this guarantee that it is probable that it will be obligated to pay and therefore has not recognized any material liabilities related to this guarantee as of September 30, 2018 . IPL’s Minnesota Electric Distribution Assets - IPL provided indemnifications associated with the July 2015 sale of its Minnesota electric distribution assets for losses resulting from potential breach of IPL’s representations, warranties and obligations under the sale agreement. Alliant Energy and IPL believe the likelihood of having to make any material cash payments under these indemnifications is remote. IPL has not recorded any material liabilities related to these indemnifications as of September 30, 2018 . The general terms of the indemnifications provided by IPL included a maximum limit of $17 million and expire in October 2020 . NOTE 13(d) Environmental Matters - Manufactured Gas Plant (MGP) Sites - IPL and WPL have current or previous ownership interests in various sites that are previously associated with the production of gas for which IPL and WPL have, or may have in the future, liability for investigation, remediation and monitoring costs. IPL and WPL are working pursuant to the requirements of various federal and state agencies to investigate, mitigate, prevent and remediate, where necessary, the environmental impacts to property, including natural resources, at and around these former MGP sites in order to protect public health and the environment. At September 30, 2018 , estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At September 30, 2018 , such amounts for WPL were not material. Alliant Energy IPL Range of estimated future costs $11 - $29 $9 - $25 Current and non-current environmental liabilities 16 13 WPL Consent Decree - In 2013, the U.S. District Court for the Western District of Wisconsin approved a Consent Decree that WPL, along with the other owners of Edgewater and Columbia, entered into with the EPA and the Sierra Club, thereby resolving claims against WPL. Such claims included allegations that the owners of Edgewater, Nelson Dewey and Columbia violated the Prevention of Significant Deterioration program requirements, Title V Operating Permit requirements of the Clean Air Act (CAA) and the Wisconsin State Implementation Plan designed to implement the CAA. WPL has completed various requirements under the Consent Decree. The Consent Decree also establishes sulfur dioxide (SO2), NOx and particulate matter emission rate limits for Columbia Units 1 and 2, and Edgewater Units 4 and 5. In addition, the Consent Decree includes annual plant-wide SO2 and NOx emission caps for Columbia and Edgewater. Alliant Energy and WPL currently expect to recover material costs incurred by WPL related to compliance with the terms of the Consent Decree from WPL’s electric customers. IPL Consent Decree - In 2015, the U.S. District Court for the Northern District of Iowa approved a Consent Decree that IPL entered into with the EPA, the Sierra Club, the State of Iowa and Linn County in Iowa, thereby resolving potential CAA issues associated with emissions from IPL’s coal-fired generating facilities in Iowa. IPL has completed various requirements under the Consent Decree. IPL’s remaining requirements include installing an SCR system or equivalent NOx reduction system at Ottumwa by December 31, 2019, and fuel switching or retiring Burlington by December 31, 2021 and Prairie Creek Units 1 and 3 by December 31, 2025. The Consent Decree also establishes SO2, NOx and particulate matter emission rate limits with varying averaging times for Burlington, Lansing, M.L. Kapp, Ottumwa and Prairie Creek. In addition, the Consent Decree includes calendar-year SO2 and NOx emission caps for Prairie Creek, and calendar-year SO2 and NOx emission caps in aggregate for Burlington, Lansing, M.L. Kapp, Ottumwa and Prairie Creek. Alliant Energy and IPL currently expect to recover material costs incurred by IPL related to compliance with the terms of the Consent Decree from IPL’s electric customers. Other Environmental Contingencies - In addition to the environmental liabilities discussed above, various environmental rules are monitored that may have a significant impact on future operations. Several of these environmental rules are subject to legal challenges, reconsideration and/or other uncertainties. Given uncertainties regarding the outcome, timing and compliance plans for these environmental matters, the complete financial impact of each of these rules is not able to be determined; however future capital investments and/or modifications to EGUs to comply with certain of these rules could be significant. Specific current, proposed or potential environmental matters include, among others: Cross-State Air Pollution Rule, Effluent Limitation Guidelines, Coal Combustion Residuals Rule, and various legislation and EPA regulations to monitor and regulate the emission of greenhouse gases, including carbon emissions from new (CAA Section 111(b)) and existing (CAA Section 111(d)) fossil-fueled EGUs. |
IPL [Member] | |
Commitments and Contingencies Disclosure | COMMITMENTS AND CONTINGENCIES NOTE 13(a) Capital Purchase Obligations - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects. IPL’s projects include the expansion of wind generation and installation of an SCR system at Ottumwa Unit 1 to reduce NOx emissions at the EGU. WPL’s projects include West Riverside. At September 30, 2018 , Alliant Energy’s, IPL’s and WPL’s minimum future commitments related to certain contractual obligations for these projects were $82 million , $26 million and $56 million , respectively. NOTE 13(b) Other Purchase Obligations - Various commodity supply, transportation and storage contracts help meet obligations to provide electricity and natural gas to utility customers. In addition, there are various purchase obligations associated with other goods and services. At September 30, 2018 , minimum future commitments related to these purchase obligations were as follows (in millions): Alliant Energy IPL WPL Purchased power (a) $1,089 $1,063 $26 Natural gas 921 394 527 Coal (b) 169 84 85 Other (c) 43 24 5 $2,222 $1,565 $643 (a) Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased. Alliant Energy’s and IPL’s amounts include minimum future commitments related to IPL’s purchase of capacity and the resulting energy from DAEC through December 2025. In July 2018, IPL entered into an amendment to shorten the term of the DAEC PPA by five years in exchange for a $110 million buyout payment by IPL in September 2020, which is not included in Alliant Energy’s and IPL’s amounts. The amendment to the DAEC PPA is contingent upon IUB approval of IPL’s July 2018 application regarding recovery of the buyout payment. (b) Corporate Services entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. These commitments were assigned to IPL and WPL based on information available as of September 30, 2018 regarding expected future usage, which is subject to change. (c) Includes individual commitments incurred during the normal course of business that exceeded $1 million at September 30, 2018 . NOTE 13(c) Guarantees and Indemnifications - Whiting Petroleum - In 2004, Alliant Energy sold its remaining interest in Whiting Petroleum. Whiting Petroleum is an independent oil and gas company. Alliant Energy Resources, LLC, as the successor to a predecessor entity that owned Whiting Petroleum, and a wholly-owned subsidiary of AEF, continues to guarantee the partnership obligations of an affiliate of Whiting Petroleum under general partnership agreements in the oil and gas industry, including with respect to the future abandonment of certain platforms off the coast of California and related onshore plant and equipment owned by the partnerships. The guarantees do not include a maximum limit. As of September 30, 2018 , the present value of the abandonment obligations is estimated at $36 million . Alliant Energy is not aware of any material liabilities related to these guarantees of which it is probable that Alliant Energy Resources, LLC will be obligated to pay and therefore has not recognized any material liabilities related to this guarantee as of September 30, 2018 . Non-utility Wind Farm in Oklahoma - In July 2017, a wholly-owned subsidiary of AEF acquired a cash equity ownership interest in a non-utility wind farm located in Oklahoma. The wind farm provides electricity to a third-party under a long-term PPA. Alliant Energy provided a parent guarantee of its subsidiary’s indemnification obligations under the related operating agreement and PPA. Alliant Energy’s obligations under the operating agreement were $90 million as of September 30, 2018 and will reduce annually until expiring in July 2047 . Alliant Energy’s obligations under the PPA are subject to a maximum limit of $17 million and expire in December 2031 , subject to potential extension. Alliant Energy is not aware of any material liabilities related to this guarantee that it is probable that it will be obligated to pay and therefore has not recognized any material liabilities related to this guarantee as of September 30, 2018 . IPL’s Minnesota Electric Distribution Assets - IPL provided indemnifications associated with the July 2015 sale of its Minnesota electric distribution assets for losses resulting from potential breach of IPL’s representations, warranties and obligations under the sale agreement. Alliant Energy and IPL believe the likelihood of having to make any material cash payments under these indemnifications is remote. IPL has not recorded any material liabilities related to these indemnifications as of September 30, 2018 . The general terms of the indemnifications provided by IPL included a maximum limit of $17 million and expire in October 2020 . NOTE 13(d) Environmental Matters - Manufactured Gas Plant (MGP) Sites - IPL and WPL have current or previous ownership interests in various sites that are previously associated with the production of gas for which IPL and WPL have, or may have in the future, liability for investigation, remediation and monitoring costs. IPL and WPL are working pursuant to the requirements of various federal and state agencies to investigate, mitigate, prevent and remediate, where necessary, the environmental impacts to property, including natural resources, at and around these former MGP sites in order to protect public health and the environment. At September 30, 2018 , estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At September 30, 2018 , such amounts for WPL were not material. Alliant Energy IPL Range of estimated future costs $11 - $29 $9 - $25 Current and non-current environmental liabilities 16 13 WPL Consent Decree - In 2013, the U.S. District Court for the Western District of Wisconsin approved a Consent Decree that WPL, along with the other owners of Edgewater and Columbia, entered into with the EPA and the Sierra Club, thereby resolving claims against WPL. Such claims included allegations that the owners of Edgewater, Nelson Dewey and Columbia violated the Prevention of Significant Deterioration program requirements, Title V Operating Permit requirements of the Clean Air Act (CAA) and the Wisconsin State Implementation Plan designed to implement the CAA. WPL has completed various requirements under the Consent Decree. The Consent Decree also establishes sulfur dioxide (SO2), NOx and particulate matter emission rate limits for Columbia Units 1 and 2, and Edgewater Units 4 and 5. In addition, the Consent Decree includes annual plant-wide SO2 and NOx emission caps for Columbia and Edgewater. Alliant Energy and WPL currently expect to recover material costs incurred by WPL related to compliance with the terms of the Consent Decree from WPL’s electric customers. IPL Consent Decree - In 2015, the U.S. District Court for the Northern District of Iowa approved a Consent Decree that IPL entered into with the EPA, the Sierra Club, the State of Iowa and Linn County in Iowa, thereby resolving potential CAA issues associated with emissions from IPL’s coal-fired generating facilities in Iowa. IPL has completed various requirements under the Consent Decree. IPL’s remaining requirements include installing an SCR system or equivalent NOx reduction system at Ottumwa by December 31, 2019, and fuel switching or retiring Burlington by December 31, 2021 and Prairie Creek Units 1 and 3 by December 31, 2025. The Consent Decree also establishes SO2, NOx and particulate matter emission rate limits with varying averaging times for Burlington, Lansing, M.L. Kapp, Ottumwa and Prairie Creek. In addition, the Consent Decree includes calendar-year SO2 and NOx emission caps for Prairie Creek, and calendar-year SO2 and NOx emission caps in aggregate for Burlington, Lansing, M.L. Kapp, Ottumwa and Prairie Creek. Alliant Energy and IPL currently expect to recover material costs incurred by IPL related to compliance with the terms of the Consent Decree from IPL’s electric customers. Other Environmental Contingencies - In addition to the environmental liabilities discussed above, various environmental rules are monitored that may have a significant impact on future operations. Several of these environmental rules are subject to legal challenges, reconsideration and/or other uncertainties. Given uncertainties regarding the outcome, timing and compliance plans for these environmental matters, the complete financial impact of each of these rules is not able to be determined; however future capital investments and/or modifications to EGUs to comply with certain of these rules could be significant. Specific current, proposed or potential environmental matters include, among others: Cross-State Air Pollution Rule, Effluent Limitation Guidelines, Coal Combustion Residuals Rule, and various legislation and EPA regulations to monitor and regulate the emission of greenhouse gases, including carbon emissions from new (CAA Section 111(b)) and existing (CAA Section 111(d)) fossil-fueled EGUs. |
WPL [Member] | |
Commitments and Contingencies Disclosure | COMMITMENTS AND CONTINGENCIES NOTE 13(a) Capital Purchase Obligations - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects. IPL’s projects include the expansion of wind generation and installation of an SCR system at Ottumwa Unit 1 to reduce NOx emissions at the EGU. WPL’s projects include West Riverside. At September 30, 2018 , Alliant Energy’s, IPL’s and WPL’s minimum future commitments related to certain contractual obligations for these projects were $82 million , $26 million and $56 million , respectively. NOTE 13(b) Other Purchase Obligations - Various commodity supply, transportation and storage contracts help meet obligations to provide electricity and natural gas to utility customers. In addition, there are various purchase obligations associated with other goods and services. At September 30, 2018 , minimum future commitments related to these purchase obligations were as follows (in millions): Alliant Energy IPL WPL Purchased power (a) $1,089 $1,063 $26 Natural gas 921 394 527 Coal (b) 169 84 85 Other (c) 43 24 5 $2,222 $1,565 $643 (a) Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased. Alliant Energy’s and IPL’s amounts include minimum future commitments related to IPL’s purchase of capacity and the resulting energy from DAEC through December 2025. In July 2018, IPL entered into an amendment to shorten the term of the DAEC PPA by five years in exchange for a $110 million buyout payment by IPL in September 2020, which is not included in Alliant Energy’s and IPL’s amounts. The amendment to the DAEC PPA is contingent upon IUB approval of IPL’s July 2018 application regarding recovery of the buyout payment. (b) Corporate Services entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. These commitments were assigned to IPL and WPL based on information available as of September 30, 2018 regarding expected future usage, which is subject to change. (c) Includes individual commitments incurred during the normal course of business that exceeded $1 million at September 30, 2018 . NOTE 13(c) Guarantees and Indemnifications - Whiting Petroleum - In 2004, Alliant Energy sold its remaining interest in Whiting Petroleum. Whiting Petroleum is an independent oil and gas company. Alliant Energy Resources, LLC, as the successor to a predecessor entity that owned Whiting Petroleum, and a wholly-owned subsidiary of AEF, continues to guarantee the partnership obligations of an affiliate of Whiting Petroleum under general partnership agreements in the oil and gas industry, including with respect to the future abandonment of certain platforms off the coast of California and related onshore plant and equipment owned by the partnerships. The guarantees do not include a maximum limit. As of September 30, 2018 , the present value of the abandonment obligations is estimated at $36 million . Alliant Energy is not aware of any material liabilities related to these guarantees of which it is probable that Alliant Energy Resources, LLC will be obligated to pay and therefore has not recognized any material liabilities related to this guarantee as of September 30, 2018 . Non-utility Wind Farm in Oklahoma - In July 2017, a wholly-owned subsidiary of AEF acquired a cash equity ownership interest in a non-utility wind farm located in Oklahoma. The wind farm provides electricity to a third-party under a long-term PPA. Alliant Energy provided a parent guarantee of its subsidiary’s indemnification obligations under the related operating agreement and PPA. Alliant Energy’s obligations under the operating agreement were $90 million as of September 30, 2018 and will reduce annually until expiring in July 2047 . Alliant Energy’s obligations under the PPA are subject to a maximum limit of $17 million and expire in December 2031 , subject to potential extension. Alliant Energy is not aware of any material liabilities related to this guarantee that it is probable that it will be obligated to pay and therefore has not recognized any material liabilities related to this guarantee as of September 30, 2018 . IPL’s Minnesota Electric Distribution Assets - IPL provided indemnifications associated with the July 2015 sale of its Minnesota electric distribution assets for losses resulting from potential breach of IPL’s representations, warranties and obligations under the sale agreement. Alliant Energy and IPL believe the likelihood of having to make any material cash payments under these indemnifications is remote. IPL has not recorded any material liabilities related to these indemnifications as of September 30, 2018 . The general terms of the indemnifications provided by IPL included a maximum limit of $17 million and expire in October 2020 . NOTE 13(d) Environmental Matters - Manufactured Gas Plant (MGP) Sites - IPL and WPL have current or previous ownership interests in various sites that are previously associated with the production of gas for which IPL and WPL have, or may have in the future, liability for investigation, remediation and monitoring costs. IPL and WPL are working pursuant to the requirements of various federal and state agencies to investigate, mitigate, prevent and remediate, where necessary, the environmental impacts to property, including natural resources, at and around these former MGP sites in order to protect public health and the environment. At September 30, 2018 , estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At September 30, 2018 , such amounts for WPL were not material. Alliant Energy IPL Range of estimated future costs $11 - $29 $9 - $25 Current and non-current environmental liabilities 16 13 WPL Consent Decree - In 2013, the U.S. District Court for the Western District of Wisconsin approved a Consent Decree that WPL, along with the other owners of Edgewater and Columbia, entered into with the EPA and the Sierra Club, thereby resolving claims against WPL. Such claims included allegations that the owners of Edgewater, Nelson Dewey and Columbia violated the Prevention of Significant Deterioration program requirements, Title V Operating Permit requirements of the Clean Air Act (CAA) and the Wisconsin State Implementation Plan designed to implement the CAA. WPL has completed various requirements under the Consent Decree. The Consent Decree also establishes sulfur dioxide (SO2), NOx and particulate matter emission rate limits for Columbia Units 1 and 2, and Edgewater Units 4 and 5. In addition, the Consent Decree includes annual plant-wide SO2 and NOx emission caps for Columbia and Edgewater. Alliant Energy and WPL currently expect to recover material costs incurred by WPL related to compliance with the terms of the Consent Decree from WPL’s electric customers. IPL Consent Decree - In 2015, the U.S. District Court for the Northern District of Iowa approved a Consent Decree that IPL entered into with the EPA, the Sierra Club, the State of Iowa and Linn County in Iowa, thereby resolving potential CAA issues associated with emissions from IPL’s coal-fired generating facilities in Iowa. IPL has completed various requirements under the Consent Decree. IPL’s remaining requirements include installing an SCR system or equivalent NOx reduction system at Ottumwa by December 31, 2019, and fuel switching or retiring Burlington by December 31, 2021 and Prairie Creek Units 1 and 3 by December 31, 2025. The Consent Decree also establishes SO2, NOx and particulate matter emission rate limits with varying averaging times for Burlington, Lansing, M.L. Kapp, Ottumwa and Prairie Creek. In addition, the Consent Decree includes calendar-year SO2 and NOx emission caps for Prairie Creek, and calendar-year SO2 and NOx emission caps in aggregate for Burlington, Lansing, M.L. Kapp, Ottumwa and Prairie Creek. Alliant Energy and IPL currently expect to recover material costs incurred by IPL related to compliance with the terms of the Consent Decree from IPL’s electric customers. Other Environmental Contingencies - In addition to the environmental liabilities discussed above, various environmental rules are monitored that may have a significant impact on future operations. Several of these environmental rules are subject to legal challenges, reconsideration and/or other uncertainties. Given uncertainties regarding the outcome, timing and compliance plans for these environmental matters, the complete financial impact of each of these rules is not able to be determined; however future capital investments and/or modifications to EGUs to comply with certain of these rules could be significant. Specific current, proposed or potential environmental matters include, among others: Cross-State Air Pollution Rule, Effluent Limitation Guidelines, Coal Combustion Residuals Rule, and various legislation and EPA regulations to monitor and regulate the emission of greenhouse gases, including carbon emissions from new (CAA Section 111(b)) and existing (CAA Section 111(d)) fossil-fueled EGUs. |
Segments Of Business
Segments Of Business | 9 Months Ended |
Sep. 30, 2018 | |
Segment Reporting Information [Line Items] | |
Segments Of Business | SEGMENTS OF BUSINESS In the fourth quarter of 2017, Alliant Energy and WPL modified the segment reporting related to ATC Holdings, consistent with information used by their chief operating decision maker to evaluate performance and allocate resources. As of December 31, 2017, ATC Holdings are no longer included in Alliant Energy’s utility electric operations reportable segment or WPL’s electric operations reportable segment. As a result, all prior period amounts impacted by this change were reclassified to conform to the new presentation. Alliant Energy’s related amounts were reclassified from “Electric Utility” to “ATC Holdings, Non-Utility, Parent and Other” in the table below. There was no resulting change to WPL’s segment reporting for the three and nine months ended September 30 , 2017. Alliant Energy - Certain financial information relating to Alliant Energy’s business segments is as follows. Intersegment revenues were not material to Alliant Energy’s operations. ATC Holdings, Alliant Utility Non-Utility, Energy Electric Gas Other Total Parent and Other Consolidated (in millions) Three Months Ended September 30, 2018 Revenues $861.2 $44.8 $12.3 $918.3 $10.3 $928.6 Operating income (loss) 248.7 (2.0 ) 0.6 247.3 8.8 256.1 Net income attributable to Alliant Energy common shareowners 202.8 2.7 205.5 Three Months Ended September 30, 2017 Revenues $840.6 $45.8 $11.2 $897.6 $9.3 $906.9 Operating income (loss) 236.7 (1.7 ) (7.7 ) 227.3 9.0 236.3 Net income (loss) attributable to Alliant Energy common shareowners 170.2 (1.4 ) 168.8 ATC Holdings, Alliant Utility Non-Utility, Energy Electric Gas Other Total Parent and Other Consolidated (in millions) Nine Months Ended September 30, 2018 Revenues $2,296.2 $299.0 $36.2 $2,631.4 $29.6 $2,661.0 Operating income 510.2 34.9 2.9 548.0 25.0 573.0 Net income attributable to Alliant Energy common shareowners 395.0 31.8 426.8 Nine Months Ended September 30, 2017 Revenues $2,199.1 $262.7 $34.4 $2,496.2 $29.9 $2,526.1 Operating income (loss) 486.9 31.3 (6.7 ) 511.5 25.7 537.2 Amounts attributable to Alliant Energy common shareowners: Income from continuing operations, net of tax 333.8 28.3 362.1 Income from discontinued operations, net of tax — 1.4 1.4 Net income 333.8 29.7 363.5 IPL - Certain financial information relating to IPL’s business segments is as follows. Intersegment revenues were not material to IPL’s operations. Electric Gas Other Total (in millions) Three Months Ended September 30, 2018 Revenues $509.2 $26.7 $11.7 $547.6 Operating income (loss) 144.7 (3.1 ) 1.5 143.1 Earnings available for common stock 126.5 Three Months Ended September 30, 2017 Revenues $489.0 $27.4 $11.0 $527.4 Operating income (loss) 140.0 (1.8 ) (4.4 ) 133.8 Earnings available for common stock 120.4 Nine Months Ended September 30, 2018 Revenues $1,337.0 $177.0 $34.2 $1,548.2 Operating income 275.7 16.3 4.4 296.4 Earnings available for common stock 224.9 Nine Months Ended September 30, 2017 Revenues $1,217.6 $147.2 $33.3 $1,398.1 Operating income (loss) 239.2 15.4 (1.4 ) 253.2 Earnings available for common stock 200.4 WPL - Certain financial information relating to WPL’s business segments is as follows. Intersegment revenues were not material to WPL’s operations. Electric Gas Other Total (in millions) Three Months Ended September 30, 2018 Revenues $352.0 $18.1 $0.6 $370.7 Operating income (loss) 104.0 1.1 (0.9 ) 104.2 Earnings available for common stock 76.3 Three Months Ended September 30, 2017 Revenues $351.6 $18.4 $0.2 $370.2 Operating income (loss) 96.7 0.1 (3.3 ) 93.5 Earnings available for common stock 49.8 Nine Months Ended September 30, 2018 Revenues $959.2 $122.0 $2.0 $1,083.2 Operating income (loss) 234.5 18.6 (1.5 ) 251.6 Earnings available for common stock 170.1 Nine Months Ended September 30, 2017 Revenues $981.5 $115.5 $1.1 $1,098.1 Operating income (loss) 247.7 15.9 (5.3 ) 258.3 Earnings available for common stock 133.4 |
IPL [Member] | |
Segment Reporting Information [Line Items] | |
Segments Of Business | SEGMENTS OF BUSINESS In the fourth quarter of 2017, Alliant Energy and WPL modified the segment reporting related to ATC Holdings, consistent with information used by their chief operating decision maker to evaluate performance and allocate resources. As of December 31, 2017, ATC Holdings are no longer included in Alliant Energy’s utility electric operations reportable segment or WPL’s electric operations reportable segment. As a result, all prior period amounts impacted by this change were reclassified to conform to the new presentation. Alliant Energy’s related amounts were reclassified from “Electric Utility” to “ATC Holdings, Non-Utility, Parent and Other” in the table below. There was no resulting change to WPL’s segment reporting for the three and nine months ended September 30 , 2017. Alliant Energy - Certain financial information relating to Alliant Energy’s business segments is as follows. Intersegment revenues were not material to Alliant Energy’s operations. ATC Holdings, Alliant Utility Non-Utility, Energy Electric Gas Other Total Parent and Other Consolidated (in millions) Three Months Ended September 30, 2018 Revenues $861.2 $44.8 $12.3 $918.3 $10.3 $928.6 Operating income (loss) 248.7 (2.0 ) 0.6 247.3 8.8 256.1 Net income attributable to Alliant Energy common shareowners 202.8 2.7 205.5 Three Months Ended September 30, 2017 Revenues $840.6 $45.8 $11.2 $897.6 $9.3 $906.9 Operating income (loss) 236.7 (1.7 ) (7.7 ) 227.3 9.0 236.3 Net income (loss) attributable to Alliant Energy common shareowners 170.2 (1.4 ) 168.8 ATC Holdings, Alliant Utility Non-Utility, Energy Electric Gas Other Total Parent and Other Consolidated (in millions) Nine Months Ended September 30, 2018 Revenues $2,296.2 $299.0 $36.2 $2,631.4 $29.6 $2,661.0 Operating income 510.2 34.9 2.9 548.0 25.0 573.0 Net income attributable to Alliant Energy common shareowners 395.0 31.8 426.8 Nine Months Ended September 30, 2017 Revenues $2,199.1 $262.7 $34.4 $2,496.2 $29.9 $2,526.1 Operating income (loss) 486.9 31.3 (6.7 ) 511.5 25.7 537.2 Amounts attributable to Alliant Energy common shareowners: Income from continuing operations, net of tax 333.8 28.3 362.1 Income from discontinued operations, net of tax — 1.4 1.4 Net income 333.8 29.7 363.5 IPL - Certain financial information relating to IPL’s business segments is as follows. Intersegment revenues were not material to IPL’s operations. Electric Gas Other Total (in millions) Three Months Ended September 30, 2018 Revenues $509.2 $26.7 $11.7 $547.6 Operating income (loss) 144.7 (3.1 ) 1.5 143.1 Earnings available for common stock 126.5 Three Months Ended September 30, 2017 Revenues $489.0 $27.4 $11.0 $527.4 Operating income (loss) 140.0 (1.8 ) (4.4 ) 133.8 Earnings available for common stock 120.4 Nine Months Ended September 30, 2018 Revenues $1,337.0 $177.0 $34.2 $1,548.2 Operating income 275.7 16.3 4.4 296.4 Earnings available for common stock 224.9 Nine Months Ended September 30, 2017 Revenues $1,217.6 $147.2 $33.3 $1,398.1 Operating income (loss) 239.2 15.4 (1.4 ) 253.2 Earnings available for common stock 200.4 WPL - Certain financial information relating to WPL’s business segments is as follows. Intersegment revenues were not material to WPL’s operations. Electric Gas Other Total (in millions) Three Months Ended September 30, 2018 Revenues $352.0 $18.1 $0.6 $370.7 Operating income (loss) 104.0 1.1 (0.9 ) 104.2 Earnings available for common stock 76.3 Three Months Ended September 30, 2017 Revenues $351.6 $18.4 $0.2 $370.2 Operating income (loss) 96.7 0.1 (3.3 ) 93.5 Earnings available for common stock 49.8 Nine Months Ended September 30, 2018 Revenues $959.2 $122.0 $2.0 $1,083.2 Operating income (loss) 234.5 18.6 (1.5 ) 251.6 Earnings available for common stock 170.1 Nine Months Ended September 30, 2017 Revenues $981.5 $115.5 $1.1 $1,098.1 Operating income (loss) 247.7 15.9 (5.3 ) 258.3 Earnings available for common stock 133.4 |
WPL [Member] | |
Segment Reporting Information [Line Items] | |
Segments Of Business | SEGMENTS OF BUSINESS In the fourth quarter of 2017, Alliant Energy and WPL modified the segment reporting related to ATC Holdings, consistent with information used by their chief operating decision maker to evaluate performance and allocate resources. As of December 31, 2017, ATC Holdings are no longer included in Alliant Energy’s utility electric operations reportable segment or WPL’s electric operations reportable segment. As a result, all prior period amounts impacted by this change were reclassified to conform to the new presentation. Alliant Energy’s related amounts were reclassified from “Electric Utility” to “ATC Holdings, Non-Utility, Parent and Other” in the table below. There was no resulting change to WPL’s segment reporting for the three and nine months ended September 30 , 2017. Alliant Energy - Certain financial information relating to Alliant Energy’s business segments is as follows. Intersegment revenues were not material to Alliant Energy’s operations. ATC Holdings, Alliant Utility Non-Utility, Energy Electric Gas Other Total Parent and Other Consolidated (in millions) Three Months Ended September 30, 2018 Revenues $861.2 $44.8 $12.3 $918.3 $10.3 $928.6 Operating income (loss) 248.7 (2.0 ) 0.6 247.3 8.8 256.1 Net income attributable to Alliant Energy common shareowners 202.8 2.7 205.5 Three Months Ended September 30, 2017 Revenues $840.6 $45.8 $11.2 $897.6 $9.3 $906.9 Operating income (loss) 236.7 (1.7 ) (7.7 ) 227.3 9.0 236.3 Net income (loss) attributable to Alliant Energy common shareowners 170.2 (1.4 ) 168.8 ATC Holdings, Alliant Utility Non-Utility, Energy Electric Gas Other Total Parent and Other Consolidated (in millions) Nine Months Ended September 30, 2018 Revenues $2,296.2 $299.0 $36.2 $2,631.4 $29.6 $2,661.0 Operating income 510.2 34.9 2.9 548.0 25.0 573.0 Net income attributable to Alliant Energy common shareowners 395.0 31.8 426.8 Nine Months Ended September 30, 2017 Revenues $2,199.1 $262.7 $34.4 $2,496.2 $29.9 $2,526.1 Operating income (loss) 486.9 31.3 (6.7 ) 511.5 25.7 537.2 Amounts attributable to Alliant Energy common shareowners: Income from continuing operations, net of tax 333.8 28.3 362.1 Income from discontinued operations, net of tax — 1.4 1.4 Net income 333.8 29.7 363.5 IPL - Certain financial information relating to IPL’s business segments is as follows. Intersegment revenues were not material to IPL’s operations. Electric Gas Other Total (in millions) Three Months Ended September 30, 2018 Revenues $509.2 $26.7 $11.7 $547.6 Operating income (loss) 144.7 (3.1 ) 1.5 143.1 Earnings available for common stock 126.5 Three Months Ended September 30, 2017 Revenues $489.0 $27.4 $11.0 $527.4 Operating income (loss) 140.0 (1.8 ) (4.4 ) 133.8 Earnings available for common stock 120.4 Nine Months Ended September 30, 2018 Revenues $1,337.0 $177.0 $34.2 $1,548.2 Operating income 275.7 16.3 4.4 296.4 Earnings available for common stock 224.9 Nine Months Ended September 30, 2017 Revenues $1,217.6 $147.2 $33.3 $1,398.1 Operating income (loss) 239.2 15.4 (1.4 ) 253.2 Earnings available for common stock 200.4 WPL - Certain financial information relating to WPL’s business segments is as follows. Intersegment revenues were not material to WPL’s operations. Electric Gas Other Total (in millions) Three Months Ended September 30, 2018 Revenues $352.0 $18.1 $0.6 $370.7 Operating income (loss) 104.0 1.1 (0.9 ) 104.2 Earnings available for common stock 76.3 Three Months Ended September 30, 2017 Revenues $351.6 $18.4 $0.2 $370.2 Operating income (loss) 96.7 0.1 (3.3 ) 93.5 Earnings available for common stock 49.8 Nine Months Ended September 30, 2018 Revenues $959.2 $122.0 $2.0 $1,083.2 Operating income (loss) 234.5 18.6 (1.5 ) 251.6 Earnings available for common stock 170.1 Nine Months Ended September 30, 2017 Revenues $981.5 $115.5 $1.1 $1,098.1 Operating income (loss) 247.7 15.9 (5.3 ) 258.3 Earnings available for common stock 133.4 |
Related Parties
Related Parties | 9 Months Ended |
Sep. 30, 2018 | |
Related Party Transactions [Line Items] | |
Related Parties | RELATED PARTIES Service Agreements - Pursuant to service agreements, IPL and WPL receive various administrative and general services from an affiliate, Corporate Services. These services are billed to IPL and WPL at cost based on expenses incurred by Corporate Services for the benefit of IPL and WPL, respectively. These costs consisted primarily of employee compensation and benefits, fees associated with various professional services, depreciation and amortization of property, plant and equipment, and a return on net assets. Corporate Services also acts as agent on behalf of IPL and WPL pursuant to the service agreements. As agent, Corporate Services enters into energy, capacity, ancillary services, and transmission sale and purchase transactions within MISO. Corporate Services assigns such sales and purchases among IPL and WPL based on statements received from MISO. The amounts billed for services provided, sales credited and purchases for the three and nine months ended September 30 were as follows (in millions): IPL WPL Three Months Nine Months Three Months Nine Months 2018 2017 2018 2017 2018 2017 2018 2017 Corporate Services billings $43 $48 $128 $130 $33 $37 $100 $100 Sales credited 11 8 34 15 7 6 16 8 Purchases billed 95 109 268 271 19 32 56 99 Net intercompany payables to Corporate Services were as follows (in millions): IPL WPL September 30, 2018 December 31, 2017 September 30, 2018 December 31, 2017 Net payables to Corporate Services $109 $114 $65 $61 ATC - Pursuant to various agreements, WPL receives a range of transmission services from ATC. WPL provides operation, maintenance, and construction services to ATC. WPL and ATC also bill each other for use of shared facilities owned by each party. The related amounts billed between the parties for the three and nine months ended September 30 were as follows (in millions): Three Months Nine Months 2018 2017 2018 2017 ATC billings to WPL $26 $26 $79 $79 WPL billings to ATC 3 2 8 8 WPL owed ATC net amounts of $8 million as of September 30, 2018 and $9 million as of December 31, 2017 . |
IPL [Member] | |
Related Party Transactions [Line Items] | |
Related Parties | RELATED PARTIES Service Agreements - Pursuant to service agreements, IPL and WPL receive various administrative and general services from an affiliate, Corporate Services. These services are billed to IPL and WPL at cost based on expenses incurred by Corporate Services for the benefit of IPL and WPL, respectively. These costs consisted primarily of employee compensation and benefits, fees associated with various professional services, depreciation and amortization of property, plant and equipment, and a return on net assets. Corporate Services also acts as agent on behalf of IPL and WPL pursuant to the service agreements. As agent, Corporate Services enters into energy, capacity, ancillary services, and transmission sale and purchase transactions within MISO. Corporate Services assigns such sales and purchases among IPL and WPL based on statements received from MISO. The amounts billed for services provided, sales credited and purchases for the three and nine months ended September 30 were as follows (in millions): IPL WPL Three Months Nine Months Three Months Nine Months 2018 2017 2018 2017 2018 2017 2018 2017 Corporate Services billings $43 $48 $128 $130 $33 $37 $100 $100 Sales credited 11 8 34 15 7 6 16 8 Purchases billed 95 109 268 271 19 32 56 99 Net intercompany payables to Corporate Services were as follows (in millions): IPL WPL September 30, 2018 December 31, 2017 September 30, 2018 December 31, 2017 Net payables to Corporate Services $109 $114 $65 $61 |
WPL [Member] | |
Related Party Transactions [Line Items] | |
Related Parties | RELATED PARTIES Service Agreements - Pursuant to service agreements, IPL and WPL receive various administrative and general services from an affiliate, Corporate Services. These services are billed to IPL and WPL at cost based on expenses incurred by Corporate Services for the benefit of IPL and WPL, respectively. These costs consisted primarily of employee compensation and benefits, fees associated with various professional services, depreciation and amortization of property, plant and equipment, and a return on net assets. Corporate Services also acts as agent on behalf of IPL and WPL pursuant to the service agreements. As agent, Corporate Services enters into energy, capacity, ancillary services, and transmission sale and purchase transactions within MISO. Corporate Services assigns such sales and purchases among IPL and WPL based on statements received from MISO. The amounts billed for services provided, sales credited and purchases for the three and nine months ended September 30 were as follows (in millions): IPL WPL Three Months Nine Months Three Months Nine Months 2018 2017 2018 2017 2018 2017 2018 2017 Corporate Services billings $43 $48 $128 $130 $33 $37 $100 $100 Sales credited 11 8 34 15 7 6 16 8 Purchases billed 95 109 268 271 19 32 56 99 Net intercompany payables to Corporate Services were as follows (in millions): IPL WPL September 30, 2018 December 31, 2017 September 30, 2018 December 31, 2017 Net payables to Corporate Services $109 $114 $65 $61 ATC - Pursuant to various agreements, WPL receives a range of transmission services from ATC. WPL provides operation, maintenance, and construction services to ATC. WPL and ATC also bill each other for use of shared facilities owned by each party. The related amounts billed between the parties for the three and nine months ended September 30 were as follows (in millions): Three Months Nine Months 2018 2017 2018 2017 ATC billings to WPL $26 $26 $79 $79 WPL billings to ATC 3 2 8 8 WPL owed ATC net amounts of $8 million as of September 30, 2018 and $9 million as of December 31, 2017 . |
Summary Of Significant Accoun_2
Summary Of Significant Accounting Policies (Policy) | 9 Months Ended |
Sep. 30, 2018 | |
General, Basis of Accounting | Discontinued operations reported in Alliant Energy’s income statements is related to various warranty claims associated with the sale of RMT, Inc. in 2013, which have resulted in operating expenses and income subsequent to the sale. The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted, although management believes that the disclosures are adequate to make the information presented not misleading. These Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the latest combined Annual Report on Form 10-K. |
General, Use of Estimates | In the opinion of management, all adjustments, which unless otherwise noted are normal and recurring in nature, necessary for a fair presentation of the results of operations, financial position and cash flows have been made. Results for the nine months ended September 30, 2018 are not necessarily indicative of results that may be expected for the year ending December 31, 2018 . A change in management’s estimates or assumptions could have a material impact on financial condition and results of operations during the period in which such change occurred. |
General, Reclassification | Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes, including modifications to the presentation of the components of net periodic benefit costs for defined benefit pension and other postretirement plans in the income statements as discussed in Note 1(d) , restricted cash and cash receipts on sold receivables in the cash flows statements as discussed in Note 1(d) , and segment reporting as discussed in Note 14 . |
Cash, Cash Equivalents and Restricted Cash | Cash, Cash Equivalents and Restricted Cash - At September 30, 2018 , Alliant Energy’s and IPL’s cash and cash equivalents included $228 million of money market fund investments with a 2% interest rate. At September 30, 2018 and December 31, 2017 , restricted cash primarily related to deposits with trustees and borrowing requirements in Sheboygan Power, LLC’s debt agreement. Refer to Note 1(d) for discussion of revisions to the cash flows statements to include immaterial restricted cash amounts. |
Revenue Recognition | Revenue Recognition - Utility - Revenues from Alliant Energy’s utility business are primarily from retail and wholesale electric and gas sales to customers. Utility revenues are recognized over time as services are rendered or commodities are delivered to customers, and include billed and unbilled components. The billed component is based on the reading of customers’ meters, which occurs on a systematic basis throughout each reporting period and represents the fair value of the services provided or commodities delivered. The unbilled component is estimated and recorded at the end of each reporting period based on estimated amounts of energy delivered to customers since the date of each customer’s last meter reading. The unbilled revenue is based on estimates of daily system demand volumes, customer usage by class, temperature impacts, line losses and the most recent customer rates. IPL and WPL accrue revenues from their wholesale customers to the extent that the actual net revenue requirements calculated in accordance with FERC-approved formula rates for the reporting period are higher or lower than the amounts billed to wholesale customers during such period. Regulatory assets or regulatory liabilities are recorded as the offset for these accrued revenues under formulaic rate-making programs. As of September 30, 2018 , the related amounts accrued for IPL and WPL were not material. IPL and WPL participate in bid/offer-based wholesale energy and ancillary services markets operated by MISO. The MISO transactions are grouped together, resulting in a net supply to or net purchase from MISO for each hour of each day. The net supply to MISO is recorded as bulk power sales in “Electric utility revenues” and the net purchase from MISO is recorded in “Electric production fuel and purchased power” in the income statements. Non-utility - Revenues from Alliant Energy’s non-utility businesses are primarily from its Transportation business and are recognized over time as services are rendered or goods are delivered to customers. Taxes Collected from Customers - Sales or various other taxes collected by certain of Alliant Energy’s subsidiaries on behalf of other agencies are recorded on a net basis and are not included in revenues. Other - Alliant Energy, IPL and WPL do not disclose the value of unsatisfied performance obligations for: (i) contracts with an original expected length of one year or less; and (ii) contracts for which revenue is recognized at the amount to which they have the right to invoice for goods delivered or services performed. |
New Accounting Standards | New Accounting Standards - Revenue Recognition - In May 2014, the Financial Accounting Standards Board issued an accounting standard providing principles for recognizing revenue for the transfer of promised goods or services to customers with the consideration to which the entity expects to be entitled in exchange for those goods or services. Alliant Energy, IPL and WPL adopted this standard on January 1, 2018 using the modified retrospective method of adoption, which was applied to contracts with customers that were completed subsequent to January 1, 2018. Alliant Energy, IPL and WPL utilized a portfolio approach upon adoption, which involved evaluating portfolios of contracts with similar characteristics, where the effects of applying the standard were not expected to be materially different than evaluating on an individual contract basis. Upon adoption, there were no cumulative effect adjustments made to the January 1, 2018 retained earnings balances. In addition, prior period amounts have not been restated to reflect the adoption of this standard and continue to be reported under the accounting standards in effect for those periods. Alliant Energy, IPL and WPL did not have a material change in revenue recognition, including the timing and pattern of revenue recognition, as a result of the adoption of this standard. Refer to Notes 1(c) and 8 for further discussion of revenue recognition. Leases - In February 2016, the Financial Accounting Standards Board issued an accounting standard requiring lease assets and lease liabilities, including operating leases, to be recognized on the balance sheet for all leases with terms longer than 12 months. The standard also requires disclosure of key information about leasing arrangements. Alliant Energy, IPL and WPL will adopt this standard on January 1, 2019 using the modified retrospective method of adoption, which requires cumulative effect adjustments to the balance sheets on January 1, 2019 upon adoption. Prior period amounts will continue to be reported under the accounting standards in effect for those periods. Alliant Energy, IPL and WPL currently plan to elect the land easement transition practical expedient, for which existing land easements that were not previously accounted for as leases under the original accounting standards do not need to be evaluated under the new accounting standard. In addition, Alliant Energy, IPL and WPL evaluated land easements that were previously accounted for as leases and determined that the majority of these land easements relate to joint-use land sites, and do not currently expect them to meet the criteria for leases under the new accounting standard. Therefore, these land easement arrangements will no longer be reflected as operating leases effective January 1, 2019. Alliant Energy, IPL and WPL will continue to evaluate the impact of this standard and do not currently expect a material change to their financial condition or results of operations as a result of adopting the new lease accounting standard. Presentation of Net Periodic Pension and Postretirement Benefit Costs - In March 2017, the Financial Accounting Standards Board issued an accounting standard amending the income statement presentation of the components of net periodic benefit costs for defined benefit pension and other postretirement plans. The standard requires entities to (1) disaggregate the current service cost component from the other components of net periodic benefit costs and present it with other employee compensation costs in the income statement; and (2) include the other components in the income statement outside of operating income. Only the service cost component of net periodic benefit costs is eligible for capitalization into property, plant and equipment; however, IPL and WPL, as rate-regulated entities, capitalize the other components of net periodic benefit costs into regulatory assets or regulatory liabilities. Alliant Energy, IPL and WPL adopted this standard on January 1, 2018 and used the retrospective method of adoption for the presentation requirements and prospective method of adoption for the capitalization requirements. Alliant Energy, IPL and WPL used the actual net periodic benefit costs adjusted for approximately 40% of net periodic benefit costs allocated to capital projects for the retrospective method of adoption for the presentation requirements. The change in presentation resulted in a decrease in “Other operation and maintenance” expenses and an increase in “Other (income) and deductions” in Alliant Energy’s, IPL’s and WPL’s income statements of $4.8 million , $2.0 million and $2.8 million for the three months ended September 30, 2017, and $13.5 million , $5.5 million and $7.9 million for the nine months ended September 30 , 2017, respectively. Cash Flows Statements - In August 2016, the Financial Accounting Standards Board issued an accounting standard providing specific guidance on several cash flow classification matters. The accounting standard requires classification of the consideration received for the beneficial interest obtained for transferring accounts receivable from IPL’s sales of accounts receivable program as an investing activity, instead of an operating activity. Alliant Energy, IPL and WPL retrospectively adopted this standard on January 1, 2018, and use a method of presentation that allocates cash flows between operating and investing activities based on daily transactional activity. For the nine months ended September 30 , 2017, Alliant Energy and IPL reclassified $432.1 million of the related cash received from IPL’s sales of accounts receivable program from operating activities to investing activities based on daily transactional activity. The related impact on Alliant Energy’s and IPL’s cash flows statements for the year ended December 31, 2017 was $461.8 million . For the three months ended March 31, 2018 and the six months ended June 30, 2018, Alliant Energy, IPL and WPL utilized a method of presentation that allocated cash flows between operating and investing activities based on monthly transactional activity. The change in method of presentation to daily transactional activity increases Alliant Energy’s operating cash flows to $156.3 million and $274.4 million , and IPL’s operating cash flows to $1.8 million and $12.8 million , for the three months ended March 31, 2018 and six months ended June 30, 2018, respectively. The change in method of presentation to daily transactional activity increases Alliant Energy’s operating cash flows to $173.5 million and $249.8 million , and IPL’s operating cash flows to $16.1 million and $15.8 million , for the three months ended March 31, 2017 and six months ended June 30, 2017, respectively. In November 2016, the Financial Accounting Standards Board issued an accounting standard requiring restricted cash to be included within beginning-of-period and end-of-period cash and cash equivalents in the cash flows statements. Alliant Energy, IPL and WPL adopted this standard on January 1, 2018, which was applied retrospectively. Refer to Note 1(b) for further discussion of restricted cash. |
IPL [Member] | |
General, Basis of Accounting | The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted, although management believes that the disclosures are adequate to make the information presented not misleading. These Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the latest combined Annual Report on Form 10-K. |
General, Use of Estimates | In the opinion of management, all adjustments, which unless otherwise noted are normal and recurring in nature, necessary for a fair presentation of the results of operations, financial position and cash flows have been made. Results for the nine months ended September 30, 2018 are not necessarily indicative of results that may be expected for the year ending December 31, 2018 . A change in management’s estimates or assumptions could have a material impact on financial condition and results of operations during the period in which such change occurred. |
General, Reclassification | Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes, including modifications to the presentation of the components of net periodic benefit costs for defined benefit pension and other postretirement plans in the income statements as discussed in Note 1(d) , restricted cash and cash receipts on sold receivables in the cash flows statements as discussed in Note 1(d) , and segment reporting as discussed in Note 14 . |
Cash, Cash Equivalents and Restricted Cash | Cash, Cash Equivalents and Restricted Cash - At September 30, 2018 , Alliant Energy’s and IPL’s cash and cash equivalents included $228 million of money market fund investments with a 2% interest rate. At September 30, 2018 and December 31, 2017 , restricted cash primarily related to deposits with trustees and borrowing requirements in Sheboygan Power, LLC’s debt agreement. Refer to Note 1(d) for discussion of revisions to the cash flows statements to include immaterial restricted cash amounts. |
Revenue Recognition | Revenue Recognition - Utility - Revenues from Alliant Energy’s utility business are primarily from retail and wholesale electric and gas sales to customers. Utility revenues are recognized over time as services are rendered or commodities are delivered to customers, and include billed and unbilled components. The billed component is based on the reading of customers’ meters, which occurs on a systematic basis throughout each reporting period and represents the fair value of the services provided or commodities delivered. The unbilled component is estimated and recorded at the end of each reporting period based on estimated amounts of energy delivered to customers since the date of each customer’s last meter reading. The unbilled revenue is based on estimates of daily system demand volumes, customer usage by class, temperature impacts, line losses and the most recent customer rates. IPL and WPL accrue revenues from their wholesale customers to the extent that the actual net revenue requirements calculated in accordance with FERC-approved formula rates for the reporting period are higher or lower than the amounts billed to wholesale customers during such period. Regulatory assets or regulatory liabilities are recorded as the offset for these accrued revenues under formulaic rate-making programs. As of September 30, 2018 , the related amounts accrued for IPL and WPL were not material. IPL and WPL participate in bid/offer-based wholesale energy and ancillary services markets operated by MISO. The MISO transactions are grouped together, resulting in a net supply to or net purchase from MISO for each hour of each day. The net supply to MISO is recorded as bulk power sales in “Electric utility revenues” and the net purchase from MISO is recorded in “Electric production fuel and purchased power” in the income statements. Non-utility - Revenues from Alliant Energy’s non-utility businesses are primarily from its Transportation business and are recognized over time as services are rendered or goods are delivered to customers. Taxes Collected from Customers - Sales or various other taxes collected by certain of Alliant Energy’s subsidiaries on behalf of other agencies are recorded on a net basis and are not included in revenues. Other - Alliant Energy, IPL and WPL do not disclose the value of unsatisfied performance obligations for: (i) contracts with an original expected length of one year or less; and (ii) contracts for which revenue is recognized at the amount to which they have the right to invoice for goods delivered or services performed. |
New Accounting Standards | New Accounting Standards - Revenue Recognition - In May 2014, the Financial Accounting Standards Board issued an accounting standard providing principles for recognizing revenue for the transfer of promised goods or services to customers with the consideration to which the entity expects to be entitled in exchange for those goods or services. Alliant Energy, IPL and WPL adopted this standard on January 1, 2018 using the modified retrospective method of adoption, which was applied to contracts with customers that were completed subsequent to January 1, 2018. Alliant Energy, IPL and WPL utilized a portfolio approach upon adoption, which involved evaluating portfolios of contracts with similar characteristics, where the effects of applying the standard were not expected to be materially different than evaluating on an individual contract basis. Upon adoption, there were no cumulative effect adjustments made to the January 1, 2018 retained earnings balances. In addition, prior period amounts have not been restated to reflect the adoption of this standard and continue to be reported under the accounting standards in effect for those periods. Alliant Energy, IPL and WPL did not have a material change in revenue recognition, including the timing and pattern of revenue recognition, as a result of the adoption of this standard. Refer to Notes 1(c) and 8 for further discussion of revenue recognition. Leases - In February 2016, the Financial Accounting Standards Board issued an accounting standard requiring lease assets and lease liabilities, including operating leases, to be recognized on the balance sheet for all leases with terms longer than 12 months. The standard also requires disclosure of key information about leasing arrangements. Alliant Energy, IPL and WPL will adopt this standard on January 1, 2019 using the modified retrospective method of adoption, which requires cumulative effect adjustments to the balance sheets on January 1, 2019 upon adoption. Prior period amounts will continue to be reported under the accounting standards in effect for those periods. Alliant Energy, IPL and WPL currently plan to elect the land easement transition practical expedient, for which existing land easements that were not previously accounted for as leases under the original accounting standards do not need to be evaluated under the new accounting standard. In addition, Alliant Energy, IPL and WPL evaluated land easements that were previously accounted for as leases and determined that the majority of these land easements relate to joint-use land sites, and do not currently expect them to meet the criteria for leases under the new accounting standard. Therefore, these land easement arrangements will no longer be reflected as operating leases effective January 1, 2019. Alliant Energy, IPL and WPL will continue to evaluate the impact of this standard and do not currently expect a material change to their financial condition or results of operations as a result of adopting the new lease accounting standard. Presentation of Net Periodic Pension and Postretirement Benefit Costs - In March 2017, the Financial Accounting Standards Board issued an accounting standard amending the income statement presentation of the components of net periodic benefit costs for defined benefit pension and other postretirement plans. The standard requires entities to (1) disaggregate the current service cost component from the other components of net periodic benefit costs and present it with other employee compensation costs in the income statement; and (2) include the other components in the income statement outside of operating income. Only the service cost component of net periodic benefit costs is eligible for capitalization into property, plant and equipment; however, IPL and WPL, as rate-regulated entities, capitalize the other components of net periodic benefit costs into regulatory assets or regulatory liabilities. Alliant Energy, IPL and WPL adopted this standard on January 1, 2018 and used the retrospective method of adoption for the presentation requirements and prospective method of adoption for the capitalization requirements. Alliant Energy, IPL and WPL used the actual net periodic benefit costs adjusted for approximately 40% of net periodic benefit costs allocated to capital projects for the retrospective method of adoption for the presentation requirements. The change in presentation resulted in a decrease in “Other operation and maintenance” expenses and an increase in “Other (income) and deductions” in Alliant Energy’s, IPL’s and WPL’s income statements of $4.8 million , $2.0 million and $2.8 million for the three months ended September 30, 2017, and $13.5 million , $5.5 million and $7.9 million for the nine months ended September 30 , 2017, respectively. Cash Flows Statements - In August 2016, the Financial Accounting Standards Board issued an accounting standard providing specific guidance on several cash flow classification matters. The accounting standard requires classification of the consideration received for the beneficial interest obtained for transferring accounts receivable from IPL’s sales of accounts receivable program as an investing activity, instead of an operating activity. Alliant Energy, IPL and WPL retrospectively adopted this standard on January 1, 2018, and use a method of presentation that allocates cash flows between operating and investing activities based on daily transactional activity. For the nine months ended September 30 , 2017, Alliant Energy and IPL reclassified $432.1 million of the related cash received from IPL’s sales of accounts receivable program from operating activities to investing activities based on daily transactional activity. The related impact on Alliant Energy’s and IPL’s cash flows statements for the year ended December 31, 2017 was $461.8 million . For the three months ended March 31, 2018 and the six months ended June 30, 2018, Alliant Energy, IPL and WPL utilized a method of presentation that allocated cash flows between operating and investing activities based on monthly transactional activity. The change in method of presentation to daily transactional activity increases Alliant Energy’s operating cash flows to $156.3 million and $274.4 million , and IPL’s operating cash flows to $1.8 million and $12.8 million , for the three months ended March 31, 2018 and six months ended June 30, 2018, respectively. The change in method of presentation to daily transactional activity increases Alliant Energy’s operating cash flows to $173.5 million and $249.8 million , and IPL’s operating cash flows to $16.1 million and $15.8 million , for the three months ended March 31, 2017 and six months ended June 30, 2017, respectively. In November 2016, the Financial Accounting Standards Board issued an accounting standard requiring restricted cash to be included within beginning-of-period and end-of-period cash and cash equivalents in the cash flows statements. Alliant Energy, IPL and WPL adopted this standard on January 1, 2018, which was applied retrospectively. Refer to Note 1(b) for further discussion of restricted cash. |
WPL [Member] | |
General, Basis of Accounting | The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted, although management believes that the disclosures are adequate to make the information presented not misleading. These Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the latest combined Annual Report on Form 10-K. |
General, Use of Estimates | In the opinion of management, all adjustments, which unless otherwise noted are normal and recurring in nature, necessary for a fair presentation of the results of operations, financial position and cash flows have been made. Results for the nine months ended September 30, 2018 are not necessarily indicative of results that may be expected for the year ending December 31, 2018 . A change in management’s estimates or assumptions could have a material impact on financial condition and results of operations during the period in which such change occurred. |
General, Reclassification | Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes, including modifications to the presentation of the components of net periodic benefit costs for defined benefit pension and other postretirement plans in the income statements as discussed in Note 1(d) , restricted cash and cash receipts on sold receivables in the cash flows statements as discussed in Note 1(d) , and segment reporting as discussed in Note 14 . |
Cash, Cash Equivalents and Restricted Cash | Cash, Cash Equivalents and Restricted Cash - At September 30, 2018 , Alliant Energy’s and IPL’s cash and cash equivalents included $228 million of money market fund investments with a 2% interest rate. At September 30, 2018 and December 31, 2017 , restricted cash primarily related to deposits with trustees and borrowing requirements in Sheboygan Power, LLC’s debt agreement. Refer to Note 1(d) for discussion of revisions to the cash flows statements to include immaterial restricted cash amounts. |
Revenue Recognition | Revenue Recognition - Utility - Revenues from Alliant Energy’s utility business are primarily from retail and wholesale electric and gas sales to customers. Utility revenues are recognized over time as services are rendered or commodities are delivered to customers, and include billed and unbilled components. The billed component is based on the reading of customers’ meters, which occurs on a systematic basis throughout each reporting period and represents the fair value of the services provided or commodities delivered. The unbilled component is estimated and recorded at the end of each reporting period based on estimated amounts of energy delivered to customers since the date of each customer’s last meter reading. The unbilled revenue is based on estimates of daily system demand volumes, customer usage by class, temperature impacts, line losses and the most recent customer rates. IPL and WPL accrue revenues from their wholesale customers to the extent that the actual net revenue requirements calculated in accordance with FERC-approved formula rates for the reporting period are higher or lower than the amounts billed to wholesale customers during such period. Regulatory assets or regulatory liabilities are recorded as the offset for these accrued revenues under formulaic rate-making programs. As of September 30, 2018 , the related amounts accrued for IPL and WPL were not material. IPL and WPL participate in bid/offer-based wholesale energy and ancillary services markets operated by MISO. The MISO transactions are grouped together, resulting in a net supply to or net purchase from MISO for each hour of each day. The net supply to MISO is recorded as bulk power sales in “Electric utility revenues” and the net purchase from MISO is recorded in “Electric production fuel and purchased power” in the income statements. Non-utility - Revenues from Alliant Energy’s non-utility businesses are primarily from its Transportation business and are recognized over time as services are rendered or goods are delivered to customers. Taxes Collected from Customers - Sales or various other taxes collected by certain of Alliant Energy’s subsidiaries on behalf of other agencies are recorded on a net basis and are not included in revenues. Other - Alliant Energy, IPL and WPL do not disclose the value of unsatisfied performance obligations for: (i) contracts with an original expected length of one year or less; and (ii) contracts for which revenue is recognized at the amount to which they have the right to invoice for goods delivered or services performed. |
New Accounting Standards | New Accounting Standards - Revenue Recognition - In May 2014, the Financial Accounting Standards Board issued an accounting standard providing principles for recognizing revenue for the transfer of promised goods or services to customers with the consideration to which the entity expects to be entitled in exchange for those goods or services. Alliant Energy, IPL and WPL adopted this standard on January 1, 2018 using the modified retrospective method of adoption, which was applied to contracts with customers that were completed subsequent to January 1, 2018. Alliant Energy, IPL and WPL utilized a portfolio approach upon adoption, which involved evaluating portfolios of contracts with similar characteristics, where the effects of applying the standard were not expected to be materially different than evaluating on an individual contract basis. Upon adoption, there were no cumulative effect adjustments made to the January 1, 2018 retained earnings balances. In addition, prior period amounts have not been restated to reflect the adoption of this standard and continue to be reported under the accounting standards in effect for those periods. Alliant Energy, IPL and WPL did not have a material change in revenue recognition, including the timing and pattern of revenue recognition, as a result of the adoption of this standard. Refer to Notes 1(c) and 8 for further discussion of revenue recognition. Leases - In February 2016, the Financial Accounting Standards Board issued an accounting standard requiring lease assets and lease liabilities, including operating leases, to be recognized on the balance sheet for all leases with terms longer than 12 months. The standard also requires disclosure of key information about leasing arrangements. Alliant Energy, IPL and WPL will adopt this standard on January 1, 2019 using the modified retrospective method of adoption, which requires cumulative effect adjustments to the balance sheets on January 1, 2019 upon adoption. Prior period amounts will continue to be reported under the accounting standards in effect for those periods. Alliant Energy, IPL and WPL currently plan to elect the land easement transition practical expedient, for which existing land easements that were not previously accounted for as leases under the original accounting standards do not need to be evaluated under the new accounting standard. In addition, Alliant Energy, IPL and WPL evaluated land easements that were previously accounted for as leases and determined that the majority of these land easements relate to joint-use land sites, and do not currently expect them to meet the criteria for leases under the new accounting standard. Therefore, these land easement arrangements will no longer be reflected as operating leases effective January 1, 2019. Alliant Energy, IPL and WPL will continue to evaluate the impact of this standard and do not currently expect a material change to their financial condition or results of operations as a result of adopting the new lease accounting standard. Presentation of Net Periodic Pension and Postretirement Benefit Costs - In March 2017, the Financial Accounting Standards Board issued an accounting standard amending the income statement presentation of the components of net periodic benefit costs for defined benefit pension and other postretirement plans. The standard requires entities to (1) disaggregate the current service cost component from the other components of net periodic benefit costs and present it with other employee compensation costs in the income statement; and (2) include the other components in the income statement outside of operating income. Only the service cost component of net periodic benefit costs is eligible for capitalization into property, plant and equipment; however, IPL and WPL, as rate-regulated entities, capitalize the other components of net periodic benefit costs into regulatory assets or regulatory liabilities. Alliant Energy, IPL and WPL adopted this standard on January 1, 2018 and used the retrospective method of adoption for the presentation requirements and prospective method of adoption for the capitalization requirements. Alliant Energy, IPL and WPL used the actual net periodic benefit costs adjusted for approximately 40% of net periodic benefit costs allocated to capital projects for the retrospective method of adoption for the presentation requirements. The change in presentation resulted in a decrease in “Other operation and maintenance” expenses and an increase in “Other (income) and deductions” in Alliant Energy’s, IPL’s and WPL’s income statements of $4.8 million , $2.0 million and $2.8 million for the three months ended September 30, 2017, and $13.5 million , $5.5 million and $7.9 million for the nine months ended September 30 , 2017, respectively. Cash Flows Statements - In August 2016, the Financial Accounting Standards Board issued an accounting standard providing specific guidance on several cash flow classification matters. The accounting standard requires classification of the consideration received for the beneficial interest obtained for transferring accounts receivable from IPL’s sales of accounts receivable program as an investing activity, instead of an operating activity. Alliant Energy, IPL and WPL retrospectively adopted this standard on January 1, 2018, and use a method of presentation that allocates cash flows between operating and investing activities based on daily transactional activity. For the nine months ended September 30 , 2017, Alliant Energy and IPL reclassified $432.1 million of the related cash received from IPL’s sales of accounts receivable program from operating activities to investing activities based on daily transactional activity. The related impact on Alliant Energy’s and IPL’s cash flows statements for the year ended December 31, 2017 was $461.8 million . For the three months ended March 31, 2018 and the six months ended June 30, 2018, Alliant Energy, IPL and WPL utilized a method of presentation that allocated cash flows between operating and investing activities based on monthly transactional activity. The change in method of presentation to daily transactional activity increases Alliant Energy’s operating cash flows to $156.3 million and $274.4 million , and IPL’s operating cash flows to $1.8 million and $12.8 million , for the three months ended March 31, 2018 and six months ended June 30, 2018, respectively. The change in method of presentation to daily transactional activity increases Alliant Energy’s operating cash flows to $173.5 million and $249.8 million , and IPL’s operating cash flows to $16.1 million and $15.8 million , for the three months ended March 31, 2017 and six months ended June 30, 2017, respectively. In November 2016, the Financial Accounting Standards Board issued an accounting standard requiring restricted cash to be included within beginning-of-period and end-of-period cash and cash equivalents in the cash flows statements. Alliant Energy, IPL and WPL adopted this standard on January 1, 2018, which was applied retrospectively. Refer to Note 1(b) for further discussion of restricted cash. |
Regulatory Matters (Tables)
Regulatory Matters (Tables) | 9 Months Ended |
Sep. 30, 2018 | |
Regulatory Assets [Line Items] | |
Regulatory Assets | Regulatory assets were comprised of the following items (in millions): Alliant Energy IPL WPL September 30, December 31, September 30, December 31, September 30, December 31, Tax-related $798.3 $778.2 $762.4 $750.5 $35.9 $27.7 Pension and OPEB costs 519.8 548.0 261.2 274.4 258.6 273.6 Asset retirement obligations 111.6 109.3 77.3 72.5 34.3 36.8 EGUs retired early 110.4 63.8 57.2 31.6 53.2 32.2 Derivatives 26.3 45.3 13.3 21.8 13.0 23.5 Emission allowances 24.3 25.5 24.3 25.5 — — Other 104.0 96.6 54.2 55.3 49.8 41.3 $1,694.7 $1,666.7 $1,249.9 $1,231.6 $444.8 $435.1 |
Regulatory Liabilities | Regulatory liabilities were comprised of the following items (in millions): Alliant Energy IPL WPL September 30, December 31, September 30, December 31, September 30, December 31, Tax-related $891.1 $899.4 $389.9 $399.5 $501.2 $499.9 Cost of removal obligations 401.0 410.0 274.0 274.5 127.0 135.5 Electric transmission cost recovery 97.0 90.4 37.9 26.4 59.1 64.0 Commodity cost recovery 20.1 21.0 13.6 14.6 6.5 6.4 IPL’s tax benefit riders 13.0 25.0 13.0 25.0 — — Other 83.4 51.4 34.2 15.4 49.2 36.0 $1,505.6 $1,497.2 $762.6 $755.4 $743.0 $741.8 |
IPL [Member] | |
Regulatory Assets [Line Items] | |
Regulatory Assets | Regulatory assets were comprised of the following items (in millions): Alliant Energy IPL WPL September 30, December 31, September 30, December 31, September 30, December 31, Tax-related $798.3 $778.2 $762.4 $750.5 $35.9 $27.7 Pension and OPEB costs 519.8 548.0 261.2 274.4 258.6 273.6 Asset retirement obligations 111.6 109.3 77.3 72.5 34.3 36.8 EGUs retired early 110.4 63.8 57.2 31.6 53.2 32.2 Derivatives 26.3 45.3 13.3 21.8 13.0 23.5 Emission allowances 24.3 25.5 24.3 25.5 — — Other 104.0 96.6 54.2 55.3 49.8 41.3 $1,694.7 $1,666.7 $1,249.9 $1,231.6 $444.8 $435.1 |
Regulatory Liabilities | Regulatory liabilities were comprised of the following items (in millions): Alliant Energy IPL WPL September 30, December 31, September 30, December 31, September 30, December 31, Tax-related $891.1 $899.4 $389.9 $399.5 $501.2 $499.9 Cost of removal obligations 401.0 410.0 274.0 274.5 127.0 135.5 Electric transmission cost recovery 97.0 90.4 37.9 26.4 59.1 64.0 Commodity cost recovery 20.1 21.0 13.6 14.6 6.5 6.4 IPL’s tax benefit riders 13.0 25.0 13.0 25.0 — — Other 83.4 51.4 34.2 15.4 49.2 36.0 $1,505.6 $1,497.2 $762.6 $755.4 $743.0 $741.8 |
WPL [Member] | |
Regulatory Assets [Line Items] | |
Regulatory Assets | Regulatory assets were comprised of the following items (in millions): Alliant Energy IPL WPL September 30, December 31, September 30, December 31, September 30, December 31, Tax-related $798.3 $778.2 $762.4 $750.5 $35.9 $27.7 Pension and OPEB costs 519.8 548.0 261.2 274.4 258.6 273.6 Asset retirement obligations 111.6 109.3 77.3 72.5 34.3 36.8 EGUs retired early 110.4 63.8 57.2 31.6 53.2 32.2 Derivatives 26.3 45.3 13.3 21.8 13.0 23.5 Emission allowances 24.3 25.5 24.3 25.5 — — Other 104.0 96.6 54.2 55.3 49.8 41.3 $1,694.7 $1,666.7 $1,249.9 $1,231.6 $444.8 $435.1 |
Regulatory Liabilities | Regulatory liabilities were comprised of the following items (in millions): Alliant Energy IPL WPL September 30, December 31, September 30, December 31, September 30, December 31, Tax-related $891.1 $899.4 $389.9 $399.5 $501.2 $499.9 Cost of removal obligations 401.0 410.0 274.0 274.5 127.0 135.5 Electric transmission cost recovery 97.0 90.4 37.9 26.4 59.1 64.0 Commodity cost recovery 20.1 21.0 13.6 14.6 6.5 6.4 IPL’s tax benefit riders 13.0 25.0 13.0 25.0 — — Other 83.4 51.4 34.2 15.4 49.2 36.0 $1,505.6 $1,497.2 $762.6 $755.4 $743.0 $741.8 |
Property, Plant and Equipment
Property, Plant and Equipment (Tables) | 9 Months Ended |
Sep. 30, 2018 | |
Property, Plant and Equipment [Line Items] | |
Assets Acquired and Liabilities Assumed | As of the closing date, the estimated fair value of the assets purchased and the liabilities assumed by WPL were as follows (in millions): Property, plant and equipment, net $81 Liabilities 7 Net assets acquired $74 |
WPL [Member] | |
Property, Plant and Equipment [Line Items] | |
Assets Acquired and Liabilities Assumed | As of the closing date, the estimated fair value of the assets purchased and the liabilities assumed by WPL were as follows (in millions): Property, plant and equipment, net $81 Liabilities 7 Net assets acquired $74 |
Receivables (Tables)
Receivables (Tables) | 9 Months Ended |
Sep. 30, 2018 | |
Receivables [Line Items] | |
Maximum And Average Outstanding Cash Proceeds | IPL’s maximum and average outstanding cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program for the three and nine months ended September 30 were as follows (in millions): Three Months Nine Months 2018 2017 2018 2017 Maximum outstanding aggregate cash proceeds $110.0 $112.0 $116.0 $112.0 Average outstanding aggregate cash proceeds 36.4 66.2 49.8 58.7 |
Receivables Sold Under The Receivables Agreement | The attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions): September 30, 2018 December 31, 2017 Customer accounts receivable $179.0 $133.8 Unbilled utility revenues 78.2 112.7 Other receivables 0.1 0.3 Receivables sold to third party 257.3 246.8 Less: cash proceeds 1.0 12.0 Deferred proceeds 256.3 234.8 Less: allowance for doubtful accounts 12.6 12.7 Fair value of deferred proceeds $243.7 $222.1 |
Additional Attributes Of Receivables Sold Under The Receivables Agreement | Additional attributes of IPL’s receivables sold under the Receivables Agreement for the three and nine months ended September 30 were as follows (in millions): Three Months Nine Months 2018 2017 2018 2017 Collections $549.5 $347.9 $1,550.2 $1,283.2 Write-offs, net of recoveries 4.9 3.5 12.9 10.4 |
IPL [Member] | |
Receivables [Line Items] | |
Maximum And Average Outstanding Cash Proceeds | IPL’s maximum and average outstanding cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program for the three and nine months ended September 30 were as follows (in millions): Three Months Nine Months 2018 2017 2018 2017 Maximum outstanding aggregate cash proceeds $110.0 $112.0 $116.0 $112.0 Average outstanding aggregate cash proceeds 36.4 66.2 49.8 58.7 |
Receivables Sold Under The Receivables Agreement | The attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions): September 30, 2018 December 31, 2017 Customer accounts receivable $179.0 $133.8 Unbilled utility revenues 78.2 112.7 Other receivables 0.1 0.3 Receivables sold to third party 257.3 246.8 Less: cash proceeds 1.0 12.0 Deferred proceeds 256.3 234.8 Less: allowance for doubtful accounts 12.6 12.7 Fair value of deferred proceeds $243.7 $222.1 |
Additional Attributes Of Receivables Sold Under The Receivables Agreement | Additional attributes of IPL’s receivables sold under the Receivables Agreement for the three and nine months ended September 30 were as follows (in millions): Three Months Nine Months 2018 2017 2018 2017 Collections $549.5 $347.9 $1,550.2 $1,283.2 Write-offs, net of recoveries 4.9 3.5 12.9 10.4 |
Investments (Tables)
Investments (Tables) | 9 Months Ended |
Sep. 30, 2018 | |
Schedule of Investments [Line Items] | |
Unconsolidated Equity Investments | Alliant Energy’s equity (income) loss from unconsolidated investments accounted for under the equity method of accounting for the three and nine months ended September 30 was as follows (in millions): Three Months Nine Months 2018 2017 2018 2017 ATC Holdings ($8.9 ) ($10.1 ) ($25.4 ) ($32.7 ) Non-utility wind farm in Oklahoma 0.1 0.2 (14.5 ) 0.2 Other (1.0 ) (0.2 ) (1.7 ) (0.4 ) ($9.8 ) ($10.1 ) ($41.6 ) ($32.9 ) |
Common Equity (Tables)
Common Equity (Tables) | 9 Months Ended |
Sep. 30, 2018 | |
Stockholders' Equity Note [Abstract] | |
Common Share Activity | A summary of Alliant Energy’s common stock activity was as follows: Shares outstanding, January 1, 2018 231,348,646 At-the-market offering program 4,171,013 Shareowner Direct Plan issuances 450,133 Equity-based compensation plans ( Note 10(b) ) 5,078 Other (38,423 ) Shares outstanding, September 30, 2018 235,936,447 |
Debt (Tables)
Debt (Tables) | 9 Months Ended |
Sep. 30, 2018 | |
Debt Disclosure [Line Items] | |
Other Short-Term Borrowings | Information regarding commercial paper classified as short-term debt was as follows (dollars in millions): September 30, 2018 Alliant Energy IPL WPL Commercial paper outstanding $136.8 $— $38.4 Commercial paper weighted average interest rates 2.4% N/A 2.2% Available credit facility capacity $863.2 $250.0 $311.6 Alliant Energy IPL WPL Three Months Ended September 30 2018 2017 2018 2017 2018 2017 Maximum amount outstanding (based on daily outstanding balances) $153.3 $424.4 $— $20.0 $75.4 $271.2 Average amount outstanding (based on daily outstanding balances) $80.8 $386.2 $— $0.4 $23.1 $217.0 Weighted average interest rates 2.2% 1.3% N/A 1.4% 2.0% 1.1% Nine Months Ended September 30 Maximum amount outstanding (based on daily outstanding balances) $446.5 $424.4 $31.4 $20.0 $109.4 $271.2 Average amount outstanding (based on daily outstanding balances) $207.6 $323.9 $1.7 $0.5 $26.6 $144.2 Weighted average interest rates 2.1% 1.1% 2.3% 1.2% 1.9% 1.0% |
IPL [Member] | |
Debt Disclosure [Line Items] | |
Other Short-Term Borrowings | Information regarding commercial paper classified as short-term debt was as follows (dollars in millions): September 30, 2018 Alliant Energy IPL WPL Commercial paper outstanding $136.8 $— $38.4 Commercial paper weighted average interest rates 2.4% N/A 2.2% Available credit facility capacity $863.2 $250.0 $311.6 Alliant Energy IPL WPL Three Months Ended September 30 2018 2017 2018 2017 2018 2017 Maximum amount outstanding (based on daily outstanding balances) $153.3 $424.4 $— $20.0 $75.4 $271.2 Average amount outstanding (based on daily outstanding balances) $80.8 $386.2 $— $0.4 $23.1 $217.0 Weighted average interest rates 2.2% 1.3% N/A 1.4% 2.0% 1.1% Nine Months Ended September 30 Maximum amount outstanding (based on daily outstanding balances) $446.5 $424.4 $31.4 $20.0 $109.4 $271.2 Average amount outstanding (based on daily outstanding balances) $207.6 $323.9 $1.7 $0.5 $26.6 $144.2 Weighted average interest rates 2.1% 1.1% 2.3% 1.2% 1.9% 1.0% |
WPL [Member] | |
Debt Disclosure [Line Items] | |
Other Short-Term Borrowings | Information regarding commercial paper classified as short-term debt was as follows (dollars in millions): September 30, 2018 Alliant Energy IPL WPL Commercial paper outstanding $136.8 $— $38.4 Commercial paper weighted average interest rates 2.4% N/A 2.2% Available credit facility capacity $863.2 $250.0 $311.6 Alliant Energy IPL WPL Three Months Ended September 30 2018 2017 2018 2017 2018 2017 Maximum amount outstanding (based on daily outstanding balances) $153.3 $424.4 $— $20.0 $75.4 $271.2 Average amount outstanding (based on daily outstanding balances) $80.8 $386.2 $— $0.4 $23.1 $217.0 Weighted average interest rates 2.2% 1.3% N/A 1.4% 2.0% 1.1% Nine Months Ended September 30 Maximum amount outstanding (based on daily outstanding balances) $446.5 $424.4 $31.4 $20.0 $109.4 $271.2 Average amount outstanding (based on daily outstanding balances) $207.6 $323.9 $1.7 $0.5 $26.6 $144.2 Weighted average interest rates 2.1% 1.1% 2.3% 1.2% 1.9% 1.0% |
Revenues Revenues (Tables)
Revenues Revenues (Tables) | 9 Months Ended |
Sep. 30, 2018 | |
Disaggregation of Revenue [Line Items] | |
Disaggregation of Revenue | Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions): Alliant Energy IPL WPL Three Months Ended September 30 2018 2017 2018 2017 2018 2017 Electric Utility: Retail - residential $312.9 $296.4 $180.1 $168.5 $132.8 $127.9 Retail - commercial 215.4 205.9 146.0 137.5 69.4 68.4 Retail - industrial 247.8 243.4 141.4 137.3 106.4 106.1 Wholesale 50.0 63.5 18.2 26.7 31.8 36.8 Bulk power and other 35.1 31.4 23.5 19.0 11.6 12.4 Total Electric Utility 861.2 840.6 509.2 489.0 352.0 351.6 Gas Utility: Retail - residential 21.8 21.5 12.6 12.0 9.2 9.5 Retail - commercial 11.0 12.9 6.4 7.8 4.6 5.1 Retail - industrial 3.0 3.0 2.0 2.2 1.0 0.8 Transportation/other 9.0 8.4 5.7 5.4 3.3 3.0 Total Gas Utility 44.8 45.8 26.7 27.4 18.1 18.4 Other Utility: Steam 8.7 8.3 8.7 8.3 — — Other utility 3.6 2.9 3.0 2.7 0.6 0.2 Total Other Utility 12.3 11.2 11.7 11.0 0.6 0.2 Non-Utility and Other: Transportation and other 10.3 9.3 — — — — Total Non-Utility and Other 10.3 9.3 — — — — Total revenues $928.6 $906.9 $547.6 $527.4 $370.7 $370.2 Alliant Energy IPL WPL Nine Months Ended September 30 2018 2017 2018 2017 2018 2017 Electric Utility: Retail - residential $820.6 $766.9 $461.6 $414.2 $359.0 $352.7 Retail - commercial 561.7 537.3 371.8 340.6 189.9 196.7 Retail - industrial 675.1 646.2 385.0 350.7 290.1 295.5 Wholesale 146.9 186.3 56.4 71.3 90.5 115.0 Bulk power and other 91.9 62.4 62.2 40.8 29.7 21.6 Total Electric Utility 2,296.2 2,199.1 1,337.0 1,217.6 959.2 981.5 Gas Utility: Retail - residential 170.1 145.1 100.9 78.7 69.2 66.4 Retail - commercial 87.3 81.4 49.8 44.4 37.5 37.0 Retail - industrial 11.4 10.4 6.1 6.8 5.3 3.6 Transportation/other 30.2 25.8 20.2 17.3 10.0 8.5 Total Gas Utility 299.0 262.7 177.0 147.2 122.0 115.5 Other Utility: Steam 26.5 25.3 26.5 25.3 — — Other utility 9.7 9.1 7.7 8.0 2.0 1.1 Total Other Utility 36.2 34.4 34.2 33.3 2.0 1.1 Non-Utility and Other: Transportation and other 29.6 29.9 — — — — Total Non-Utility and Other 29.6 29.9 — — — — Total revenues $2,661.0 $2,526.1 $1,548.2 $1,398.1 $1,083.2 $1,098.1 |
IPL [Member] | |
Disaggregation of Revenue [Line Items] | |
Disaggregation of Revenue | Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions): Alliant Energy IPL WPL Three Months Ended September 30 2018 2017 2018 2017 2018 2017 Electric Utility: Retail - residential $312.9 $296.4 $180.1 $168.5 $132.8 $127.9 Retail - commercial 215.4 205.9 146.0 137.5 69.4 68.4 Retail - industrial 247.8 243.4 141.4 137.3 106.4 106.1 Wholesale 50.0 63.5 18.2 26.7 31.8 36.8 Bulk power and other 35.1 31.4 23.5 19.0 11.6 12.4 Total Electric Utility 861.2 840.6 509.2 489.0 352.0 351.6 Gas Utility: Retail - residential 21.8 21.5 12.6 12.0 9.2 9.5 Retail - commercial 11.0 12.9 6.4 7.8 4.6 5.1 Retail - industrial 3.0 3.0 2.0 2.2 1.0 0.8 Transportation/other 9.0 8.4 5.7 5.4 3.3 3.0 Total Gas Utility 44.8 45.8 26.7 27.4 18.1 18.4 Other Utility: Steam 8.7 8.3 8.7 8.3 — — Other utility 3.6 2.9 3.0 2.7 0.6 0.2 Total Other Utility 12.3 11.2 11.7 11.0 0.6 0.2 Non-Utility and Other: Transportation and other 10.3 9.3 — — — — Total Non-Utility and Other 10.3 9.3 — — — — Total revenues $928.6 $906.9 $547.6 $527.4 $370.7 $370.2 Alliant Energy IPL WPL Nine Months Ended September 30 2018 2017 2018 2017 2018 2017 Electric Utility: Retail - residential $820.6 $766.9 $461.6 $414.2 $359.0 $352.7 Retail - commercial 561.7 537.3 371.8 340.6 189.9 196.7 Retail - industrial 675.1 646.2 385.0 350.7 290.1 295.5 Wholesale 146.9 186.3 56.4 71.3 90.5 115.0 Bulk power and other 91.9 62.4 62.2 40.8 29.7 21.6 Total Electric Utility 2,296.2 2,199.1 1,337.0 1,217.6 959.2 981.5 Gas Utility: Retail - residential 170.1 145.1 100.9 78.7 69.2 66.4 Retail - commercial 87.3 81.4 49.8 44.4 37.5 37.0 Retail - industrial 11.4 10.4 6.1 6.8 5.3 3.6 Transportation/other 30.2 25.8 20.2 17.3 10.0 8.5 Total Gas Utility 299.0 262.7 177.0 147.2 122.0 115.5 Other Utility: Steam 26.5 25.3 26.5 25.3 — — Other utility 9.7 9.1 7.7 8.0 2.0 1.1 Total Other Utility 36.2 34.4 34.2 33.3 2.0 1.1 Non-Utility and Other: Transportation and other 29.6 29.9 — — — — Total Non-Utility and Other 29.6 29.9 — — — — Total revenues $2,661.0 $2,526.1 $1,548.2 $1,398.1 $1,083.2 $1,098.1 |
WPL [Member] | |
Disaggregation of Revenue [Line Items] | |
Disaggregation of Revenue | Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions): Alliant Energy IPL WPL Three Months Ended September 30 2018 2017 2018 2017 2018 2017 Electric Utility: Retail - residential $312.9 $296.4 $180.1 $168.5 $132.8 $127.9 Retail - commercial 215.4 205.9 146.0 137.5 69.4 68.4 Retail - industrial 247.8 243.4 141.4 137.3 106.4 106.1 Wholesale 50.0 63.5 18.2 26.7 31.8 36.8 Bulk power and other 35.1 31.4 23.5 19.0 11.6 12.4 Total Electric Utility 861.2 840.6 509.2 489.0 352.0 351.6 Gas Utility: Retail - residential 21.8 21.5 12.6 12.0 9.2 9.5 Retail - commercial 11.0 12.9 6.4 7.8 4.6 5.1 Retail - industrial 3.0 3.0 2.0 2.2 1.0 0.8 Transportation/other 9.0 8.4 5.7 5.4 3.3 3.0 Total Gas Utility 44.8 45.8 26.7 27.4 18.1 18.4 Other Utility: Steam 8.7 8.3 8.7 8.3 — — Other utility 3.6 2.9 3.0 2.7 0.6 0.2 Total Other Utility 12.3 11.2 11.7 11.0 0.6 0.2 Non-Utility and Other: Transportation and other 10.3 9.3 — — — — Total Non-Utility and Other 10.3 9.3 — — — — Total revenues $928.6 $906.9 $547.6 $527.4 $370.7 $370.2 Alliant Energy IPL WPL Nine Months Ended September 30 2018 2017 2018 2017 2018 2017 Electric Utility: Retail - residential $820.6 $766.9 $461.6 $414.2 $359.0 $352.7 Retail - commercial 561.7 537.3 371.8 340.6 189.9 196.7 Retail - industrial 675.1 646.2 385.0 350.7 290.1 295.5 Wholesale 146.9 186.3 56.4 71.3 90.5 115.0 Bulk power and other 91.9 62.4 62.2 40.8 29.7 21.6 Total Electric Utility 2,296.2 2,199.1 1,337.0 1,217.6 959.2 981.5 Gas Utility: Retail - residential 170.1 145.1 100.9 78.7 69.2 66.4 Retail - commercial 87.3 81.4 49.8 44.4 37.5 37.0 Retail - industrial 11.4 10.4 6.1 6.8 5.3 3.6 Transportation/other 30.2 25.8 20.2 17.3 10.0 8.5 Total Gas Utility 299.0 262.7 177.0 147.2 122.0 115.5 Other Utility: Steam 26.5 25.3 26.5 25.3 — — Other utility 9.7 9.1 7.7 8.0 2.0 1.1 Total Other Utility 36.2 34.4 34.2 33.3 2.0 1.1 Non-Utility and Other: Transportation and other 29.6 29.9 — — — — Total Non-Utility and Other 29.6 29.9 — — — — Total revenues $2,661.0 $2,526.1 $1,548.2 $1,398.1 $1,083.2 $1,098.1 |
Income Taxes (Tables)
Income Taxes (Tables) | 9 Months Ended |
Sep. 30, 2018 | |
Income Taxes [Line Items] | |
Schedule Of Effective Income Tax Rates | The overall income tax rates shown in the following table were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes. Alliant Energy IPL WPL Three Months Ended September 30 2018 2017 2018 2017 2018 2017 Statutory federal income tax rate 21.0 % 35.0 % 21.0 % 35.0 % 21.0 % 35.0 % State income taxes, net of federal benefits 6.9 5.7 7.7 6.5 6.2 5.2 Effect of rate-making on property-related differences (6.3 ) (10.1 ) (11.5 ) (22.6 ) (2.1 ) (1.9 ) Production tax credits (5.4 ) (6.2 ) (5.5 ) (7.0 ) (6.4 ) (7.0 ) Adjustment for prior period taxes (5.7 ) (2.0 ) (10.2 ) (3.5 ) — 0.8 IPL’s tax benefit riders (2.3 ) (8.3 ) (4.8 ) (20.9 ) — — Federal Tax Reform adjustments (2.5 ) — (0.9 ) — (6.4 ) — Other items, net (0.4 ) (0.9 ) (0.6 ) (0.7 ) (0.5 ) (0.5 ) Overall income tax rate 5.3 % 13.2 % (4.8 %) (13.2 %) 11.8 % 31.6 % Alliant Energy IPL WPL Nine Months Ended September 30 2018 2017 2018 2017 2018 2017 Statutory federal income tax rate 21.0 % 35.0 % 21.0 % 35.0 % 21.0 % 35.0 % State income taxes, net of federal benefits 6.9 5.6 7.7 6.5 6.2 5.1 Effect of rate-making on property-related differences (6.7 ) (9.1 ) (12.0 ) (20.6 ) (2.3 ) (1.8 ) Production tax credits (5.4 ) (6.0 ) (5.4 ) (6.8 ) (6.6 ) (7.0 ) Adjustment for prior period taxes (2.6 ) (1.3 ) (5.4 ) (3.3 ) — 0.3 IPL’s tax benefit riders (2.2 ) (8.1 ) (4.6 ) (20.1 ) — — Federal Tax Reform adjustments (1.2 ) — (0.5 ) — (2.8 ) — Other items, net (1.0 ) (1.2 ) (1.0 ) (0.5 ) (1.3 ) (0.5 ) Overall income tax rate 8.8 % 14.9 % (0.2 %) (9.8 %) 14.2 % 31.1 % |
Summary Of Tax Credit Carryforwards | At September 30, 2018 , carryforwards and expiration dates were estimated as follows (in millions): Range of Expiration Dates Alliant Energy IPL WPL Federal net operating losses 2030-2037 $804 $563 $144 State net operating losses 2018-2038 765 13 2 Federal tax credits 2022-2038 290 129 143 |
IPL [Member] | |
Income Taxes [Line Items] | |
Schedule Of Effective Income Tax Rates | The overall income tax rates shown in the following table were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes. Alliant Energy IPL WPL Three Months Ended September 30 2018 2017 2018 2017 2018 2017 Statutory federal income tax rate 21.0 % 35.0 % 21.0 % 35.0 % 21.0 % 35.0 % State income taxes, net of federal benefits 6.9 5.7 7.7 6.5 6.2 5.2 Effect of rate-making on property-related differences (6.3 ) (10.1 ) (11.5 ) (22.6 ) (2.1 ) (1.9 ) Production tax credits (5.4 ) (6.2 ) (5.5 ) (7.0 ) (6.4 ) (7.0 ) Adjustment for prior period taxes (5.7 ) (2.0 ) (10.2 ) (3.5 ) — 0.8 IPL’s tax benefit riders (2.3 ) (8.3 ) (4.8 ) (20.9 ) — — Federal Tax Reform adjustments (2.5 ) — (0.9 ) — (6.4 ) — Other items, net (0.4 ) (0.9 ) (0.6 ) (0.7 ) (0.5 ) (0.5 ) Overall income tax rate 5.3 % 13.2 % (4.8 %) (13.2 %) 11.8 % 31.6 % Alliant Energy IPL WPL Nine Months Ended September 30 2018 2017 2018 2017 2018 2017 Statutory federal income tax rate 21.0 % 35.0 % 21.0 % 35.0 % 21.0 % 35.0 % State income taxes, net of federal benefits 6.9 5.6 7.7 6.5 6.2 5.1 Effect of rate-making on property-related differences (6.7 ) (9.1 ) (12.0 ) (20.6 ) (2.3 ) (1.8 ) Production tax credits (5.4 ) (6.0 ) (5.4 ) (6.8 ) (6.6 ) (7.0 ) Adjustment for prior period taxes (2.6 ) (1.3 ) (5.4 ) (3.3 ) — 0.3 IPL’s tax benefit riders (2.2 ) (8.1 ) (4.6 ) (20.1 ) — — Federal Tax Reform adjustments (1.2 ) — (0.5 ) — (2.8 ) — Other items, net (1.0 ) (1.2 ) (1.0 ) (0.5 ) (1.3 ) (0.5 ) Overall income tax rate 8.8 % 14.9 % (0.2 %) (9.8 %) 14.2 % 31.1 % |
Summary Of Tax Credit Carryforwards | At September 30, 2018 , carryforwards and expiration dates were estimated as follows (in millions): Range of Expiration Dates Alliant Energy IPL WPL Federal net operating losses 2030-2037 $804 $563 $144 State net operating losses 2018-2038 765 13 2 Federal tax credits 2022-2038 290 129 143 |
WPL [Member] | |
Income Taxes [Line Items] | |
Schedule Of Effective Income Tax Rates | The overall income tax rates shown in the following table were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes. Alliant Energy IPL WPL Three Months Ended September 30 2018 2017 2018 2017 2018 2017 Statutory federal income tax rate 21.0 % 35.0 % 21.0 % 35.0 % 21.0 % 35.0 % State income taxes, net of federal benefits 6.9 5.7 7.7 6.5 6.2 5.2 Effect of rate-making on property-related differences (6.3 ) (10.1 ) (11.5 ) (22.6 ) (2.1 ) (1.9 ) Production tax credits (5.4 ) (6.2 ) (5.5 ) (7.0 ) (6.4 ) (7.0 ) Adjustment for prior period taxes (5.7 ) (2.0 ) (10.2 ) (3.5 ) — 0.8 IPL’s tax benefit riders (2.3 ) (8.3 ) (4.8 ) (20.9 ) — — Federal Tax Reform adjustments (2.5 ) — (0.9 ) — (6.4 ) — Other items, net (0.4 ) (0.9 ) (0.6 ) (0.7 ) (0.5 ) (0.5 ) Overall income tax rate 5.3 % 13.2 % (4.8 %) (13.2 %) 11.8 % 31.6 % Alliant Energy IPL WPL Nine Months Ended September 30 2018 2017 2018 2017 2018 2017 Statutory federal income tax rate 21.0 % 35.0 % 21.0 % 35.0 % 21.0 % 35.0 % State income taxes, net of federal benefits 6.9 5.6 7.7 6.5 6.2 5.1 Effect of rate-making on property-related differences (6.7 ) (9.1 ) (12.0 ) (20.6 ) (2.3 ) (1.8 ) Production tax credits (5.4 ) (6.0 ) (5.4 ) (6.8 ) (6.6 ) (7.0 ) Adjustment for prior period taxes (2.6 ) (1.3 ) (5.4 ) (3.3 ) — 0.3 IPL’s tax benefit riders (2.2 ) (8.1 ) (4.6 ) (20.1 ) — — Federal Tax Reform adjustments (1.2 ) — (0.5 ) — (2.8 ) — Other items, net (1.0 ) (1.2 ) (1.0 ) (0.5 ) (1.3 ) (0.5 ) Overall income tax rate 8.8 % 14.9 % (0.2 %) (9.8 %) 14.2 % 31.1 % |
Summary Of Tax Credit Carryforwards | At September 30, 2018 , carryforwards and expiration dates were estimated as follows (in millions): Range of Expiration Dates Alliant Energy IPL WPL Federal net operating losses 2030-2037 $804 $563 $144 State net operating losses 2018-2038 765 13 2 Federal tax credits 2022-2038 290 129 143 |
Benefit Plans (Tables)
Benefit Plans (Tables) | 9 Months Ended |
Sep. 30, 2018 | |
Defined Benefit Plan Disclosure [Line Items] | |
Defined Benefit Pension And Other Postretirement Benefits Plans | The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and nine months ended September 30 are included in the tables below (in millions). The service cost component of net periodic benefit costs is included in “Other operation and maintenance” expenses in the income statements and all other components of net periodic benefit costs are included in “Other (income) and deductions” in the income statements. In IPL’s and WPL’s tables below, the defined benefit pension plan amounts represent those respective amounts for their bargaining unit employees covered under the qualified plans that they sponsor, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans. In IPL’s and WPL’s tables below, the OPEB plan amounts represent respective amounts for their employees, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Corporate Services sponsored OPEB plan. Defined Benefit Pension Plans OPEB Plans Three Months Nine Months Three Months Nine Months Alliant Energy 2018 2017 2018 2017 2018 2017 2018 2017 Service cost $3.1 $3.1 $9.1 $9.3 $1.0 $1.2 $3.1 $3.7 Interest cost 11.7 12.7 35.1 38.3 2.0 2.2 5.8 6.5 Expected return on plan assets (17.4 ) (16.3 ) (52.3 ) (49.1 ) (1.5 ) (1.5 ) (4.5 ) (4.6 ) Amortization of prior service credit (0.2 ) (0.1 ) (0.5 ) (0.3 ) — (0.1 ) (0.1 ) (0.2 ) Amortization of actuarial loss 8.8 9.4 26.4 28.2 0.8 1.0 2.5 2.9 Settlement losses (a) — 0.9 — 0.9 — — — — $6.0 $9.7 $17.8 $27.3 $2.3 $2.8 $6.8 $8.3 Defined Benefit Pension Plans OPEB Plans Three Months Nine Months Three Months Nine Months IPL 2018 2017 2018 2017 2018 2017 2018 2017 Service cost $1.8 $1.8 $5.5 $5.5 $0.4 $0.5 $1.3 $1.6 Interest cost 5.3 5.9 16.0 17.6 0.7 0.8 2.3 2.6 Expected return on plan assets (8.1 ) (7.7 ) (24.4 ) (23.1 ) (1.1 ) (1.0 ) (3.3 ) (3.2 ) Amortization of prior service credit — — (0.1 ) (0.1 ) — — — — Amortization of actuarial loss 3.7 4.0 11.2 12.1 0.4 0.5 1.0 1.5 $2.7 $4.0 $8.2 $12.0 $0.4 $0.8 $1.3 $2.5 Defined Benefit Pension Plans OPEB Plans Three Months Nine Months Three Months Nine Months WPL 2018 2017 2018 2017 2018 2017 2018 2017 Service cost $1.1 $1.2 $3.3 $3.6 $0.4 $0.5 $1.2 $1.4 Interest cost 5.0 5.5 15.1 16.4 0.8 0.9 2.3 2.6 Expected return on plan assets (7.6 ) (7.2 ) (22.8 ) (21.4 ) (0.2 ) (0.2 ) (0.5 ) (0.6 ) Amortization of prior service cost (credit) — 0.1 (0.1 ) 0.1 — (0.1 ) (0.1 ) (0.2 ) Amortization of actuarial loss 4.3 4.6 12.9 13.9 0.5 0.4 1.5 1.2 $2.8 $4.2 $8.4 $12.6 $1.5 $1.5 $4.4 $4.4 (a) Settlement losses related to payments made to retired executives of Alliant Energy. |
Recognized Compensation Expense And Income Tax Benefits | A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three and nine months ended September 30 was as follows (in millions): Alliant Energy IPL WPL Three Months Nine Months Three Months Nine Months Three Months Nine Months 2018 2017 2018 2017 2018 2017 2018 2017 2018 2017 2018 2017 Compensation expense $4.2 $5.1 $12.6 $9.9 $2.4 $2.8 $7.0 $5.4 $1.7 $2.1 $5.1 $4.1 Income tax benefits 1.2 2.1 3.6 4.0 0.7 1.1 2.1 2.2 0.5 0.9 1.4 1.7 |
Performance Shares and Performance Units [Member] | |
Defined Benefit Plan Disclosure [Line Items] | |
Schedule Of Equity-based Compensation Plans Activity | A summary of the performance shares and performance units activity for the nine months ended September 30 , 2018 , with amounts representing the target number of awards, was as follows: Performance Shares Performance Units Nonvested awards, January 1 223,511 71,737 Granted 74,163 19,840 Vested (90,806 ) (31,910 ) Forfeited (905 ) (1,906 ) Nonvested awards, September 30 205,963 57,761 Vested Awards - During the nine months ended September 30 , 2018 , certain performance shares and performance units that were granted in 2015 vested, resulting in payouts (a combination of cash and common stock for the performance shares and cash only for the performance units) as follows: Performance Shares Performance Units Performance awards vested 90,806 31,910 Percentage of target number of performance awards 137.5 % 137.5 % Aggregate payout value (in millions) $5.3 $1.4 Payout - cash (in millions) $4.9 $1.4 Payout - common stock shares issued 5,078 N/A Fair Value of Awards - At September 28, 2018 , Alliant Energy’s common stock closing price was $42.57 . Additional information related to fair values of nonvested performance shares and performance units at September 30, 2018 , by year of grant, was as follows: Performance Shares Performance Units 2018 Grant 2017 Grant 2016 Grant 2018 Grant 2017 Grant 2016 Grant Nonvested awards at target 73,258 65,350 67,355 19,196 18,062 20,503 Estimated payout percentage based on performance criteria 85 % 105 % 143 % 85 % 105 % 143 % Fair values of each nonvested award $36.18 $44.70 $60.88 $36.18 $44.70 $60.88 |
Performance Restricted Stock Unit [Member] | |
Defined Benefit Plan Disclosure [Line Items] | |
Schedule Of Equity-based Compensation Plans Activity | A summary of the performance restricted stock units activity for the nine months ended September 30 , 2018 , with amounts representing the target number of units, was as follows: Units Weighted Average Grant Date Fair Value Nonvested units, January 1 132,705 $36.50 Granted 74,163 38.60 Forfeited (905 ) 38.60 Nonvested units, September 30 205,963 37.25 |
Restricted Stock Unit [Member] | |
Defined Benefit Plan Disclosure [Line Items] | |
Schedule Of Equity-based Compensation Plans Activity | A summary of the restricted stock units activity for the nine months ended September 30 , 2018 , was as follows: Nonvested units, January 1 113,749 Granted 63,568 Forfeited (775 ) Nonvested units, September 30 176,542 |
IPL [Member] | |
Defined Benefit Plan Disclosure [Line Items] | |
Defined Benefit Pension And Other Postretirement Benefits Plans | The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and nine months ended September 30 are included in the tables below (in millions). The service cost component of net periodic benefit costs is included in “Other operation and maintenance” expenses in the income statements and all other components of net periodic benefit costs are included in “Other (income) and deductions” in the income statements. In IPL’s and WPL’s tables below, the defined benefit pension plan amounts represent those respective amounts for their bargaining unit employees covered under the qualified plans that they sponsor, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans. In IPL’s and WPL’s tables below, the OPEB plan amounts represent respective amounts for their employees, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Corporate Services sponsored OPEB plan. Defined Benefit Pension Plans OPEB Plans Three Months Nine Months Three Months Nine Months Alliant Energy 2018 2017 2018 2017 2018 2017 2018 2017 Service cost $3.1 $3.1 $9.1 $9.3 $1.0 $1.2 $3.1 $3.7 Interest cost 11.7 12.7 35.1 38.3 2.0 2.2 5.8 6.5 Expected return on plan assets (17.4 ) (16.3 ) (52.3 ) (49.1 ) (1.5 ) (1.5 ) (4.5 ) (4.6 ) Amortization of prior service credit (0.2 ) (0.1 ) (0.5 ) (0.3 ) — (0.1 ) (0.1 ) (0.2 ) Amortization of actuarial loss 8.8 9.4 26.4 28.2 0.8 1.0 2.5 2.9 Settlement losses (a) — 0.9 — 0.9 — — — — $6.0 $9.7 $17.8 $27.3 $2.3 $2.8 $6.8 $8.3 Defined Benefit Pension Plans OPEB Plans Three Months Nine Months Three Months Nine Months IPL 2018 2017 2018 2017 2018 2017 2018 2017 Service cost $1.8 $1.8 $5.5 $5.5 $0.4 $0.5 $1.3 $1.6 Interest cost 5.3 5.9 16.0 17.6 0.7 0.8 2.3 2.6 Expected return on plan assets (8.1 ) (7.7 ) (24.4 ) (23.1 ) (1.1 ) (1.0 ) (3.3 ) (3.2 ) Amortization of prior service credit — — (0.1 ) (0.1 ) — — — — Amortization of actuarial loss 3.7 4.0 11.2 12.1 0.4 0.5 1.0 1.5 $2.7 $4.0 $8.2 $12.0 $0.4 $0.8 $1.3 $2.5 Defined Benefit Pension Plans OPEB Plans Three Months Nine Months Three Months Nine Months WPL 2018 2017 2018 2017 2018 2017 2018 2017 Service cost $1.1 $1.2 $3.3 $3.6 $0.4 $0.5 $1.2 $1.4 Interest cost 5.0 5.5 15.1 16.4 0.8 0.9 2.3 2.6 Expected return on plan assets (7.6 ) (7.2 ) (22.8 ) (21.4 ) (0.2 ) (0.2 ) (0.5 ) (0.6 ) Amortization of prior service cost (credit) — 0.1 (0.1 ) 0.1 — (0.1 ) (0.1 ) (0.2 ) Amortization of actuarial loss 4.3 4.6 12.9 13.9 0.5 0.4 1.5 1.2 $2.8 $4.2 $8.4 $12.6 $1.5 $1.5 $4.4 $4.4 (a) Settlement losses related to payments made to retired executives of Alliant Energy. |
Recognized Compensation Expense And Income Tax Benefits | A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three and nine months ended September 30 was as follows (in millions): Alliant Energy IPL WPL Three Months Nine Months Three Months Nine Months Three Months Nine Months 2018 2017 2018 2017 2018 2017 2018 2017 2018 2017 2018 2017 Compensation expense $4.2 $5.1 $12.6 $9.9 $2.4 $2.8 $7.0 $5.4 $1.7 $2.1 $5.1 $4.1 Income tax benefits 1.2 2.1 3.6 4.0 0.7 1.1 2.1 2.2 0.5 0.9 1.4 1.7 |
WPL [Member] | |
Defined Benefit Plan Disclosure [Line Items] | |
Defined Benefit Pension And Other Postretirement Benefits Plans | The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and nine months ended September 30 are included in the tables below (in millions). The service cost component of net periodic benefit costs is included in “Other operation and maintenance” expenses in the income statements and all other components of net periodic benefit costs are included in “Other (income) and deductions” in the income statements. In IPL’s and WPL’s tables below, the defined benefit pension plan amounts represent those respective amounts for their bargaining unit employees covered under the qualified plans that they sponsor, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans. In IPL’s and WPL’s tables below, the OPEB plan amounts represent respective amounts for their employees, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Corporate Services sponsored OPEB plan. Defined Benefit Pension Plans OPEB Plans Three Months Nine Months Three Months Nine Months Alliant Energy 2018 2017 2018 2017 2018 2017 2018 2017 Service cost $3.1 $3.1 $9.1 $9.3 $1.0 $1.2 $3.1 $3.7 Interest cost 11.7 12.7 35.1 38.3 2.0 2.2 5.8 6.5 Expected return on plan assets (17.4 ) (16.3 ) (52.3 ) (49.1 ) (1.5 ) (1.5 ) (4.5 ) (4.6 ) Amortization of prior service credit (0.2 ) (0.1 ) (0.5 ) (0.3 ) — (0.1 ) (0.1 ) (0.2 ) Amortization of actuarial loss 8.8 9.4 26.4 28.2 0.8 1.0 2.5 2.9 Settlement losses (a) — 0.9 — 0.9 — — — — $6.0 $9.7 $17.8 $27.3 $2.3 $2.8 $6.8 $8.3 Defined Benefit Pension Plans OPEB Plans Three Months Nine Months Three Months Nine Months IPL 2018 2017 2018 2017 2018 2017 2018 2017 Service cost $1.8 $1.8 $5.5 $5.5 $0.4 $0.5 $1.3 $1.6 Interest cost 5.3 5.9 16.0 17.6 0.7 0.8 2.3 2.6 Expected return on plan assets (8.1 ) (7.7 ) (24.4 ) (23.1 ) (1.1 ) (1.0 ) (3.3 ) (3.2 ) Amortization of prior service credit — — (0.1 ) (0.1 ) — — — — Amortization of actuarial loss 3.7 4.0 11.2 12.1 0.4 0.5 1.0 1.5 $2.7 $4.0 $8.2 $12.0 $0.4 $0.8 $1.3 $2.5 Defined Benefit Pension Plans OPEB Plans Three Months Nine Months Three Months Nine Months WPL 2018 2017 2018 2017 2018 2017 2018 2017 Service cost $1.1 $1.2 $3.3 $3.6 $0.4 $0.5 $1.2 $1.4 Interest cost 5.0 5.5 15.1 16.4 0.8 0.9 2.3 2.6 Expected return on plan assets (7.6 ) (7.2 ) (22.8 ) (21.4 ) (0.2 ) (0.2 ) (0.5 ) (0.6 ) Amortization of prior service cost (credit) — 0.1 (0.1 ) 0.1 — (0.1 ) (0.1 ) (0.2 ) Amortization of actuarial loss 4.3 4.6 12.9 13.9 0.5 0.4 1.5 1.2 $2.8 $4.2 $8.4 $12.6 $1.5 $1.5 $4.4 $4.4 (a) Settlement losses related to payments made to retired executives of Alliant Energy. |
Recognized Compensation Expense And Income Tax Benefits | A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three and nine months ended September 30 was as follows (in millions): Alliant Energy IPL WPL Three Months Nine Months Three Months Nine Months Three Months Nine Months 2018 2017 2018 2017 2018 2017 2018 2017 2018 2017 2018 2017 Compensation expense $4.2 $5.1 $12.6 $9.9 $2.4 $2.8 $7.0 $5.4 $1.7 $2.1 $5.1 $4.1 Income tax benefits 1.2 2.1 3.6 4.0 0.7 1.1 2.1 2.2 0.5 0.9 1.4 1.7 |
Fair Value Measurements (Tables
Fair Value Measurements (Tables) | 9 Months Ended |
Sep. 30, 2018 | |
Statement [Line Items] | |
Fair Value Measurements | Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions): Alliant Energy September 30, 2018 December 31, 2017 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $228.0 $228.0 $— $— $228.0 $— $— $— $— $— Derivatives 48.0 — 16.5 31.5 48.0 25.1 — 4.1 21.0 25.1 Deferred proceeds 243.7 — — 243.7 243.7 222.1 — — 222.1 222.1 Liabilities and equity: Derivatives 22.0 — 14.7 7.3 22.0 41.7 — 8.5 33.2 41.7 Long-term debt (incl. current maturities) 5,754.3 — 6,057.8 2.5 6,060.3 4,866.3 — 5,444.6 2.9 5,447.5 Cumulative preferred stock of IPL 200.0 200.0 — — 200.0 200.0 203.8 — — 203.8 IPL September 30, 2018 December 31, 2017 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $228.0 $228.0 $— $— $228.0 $— $— $— $— $— Derivatives 29.1 — 6.7 22.4 29.1 17.1 — 2.0 15.1 17.1 Deferred proceeds 243.7 — — 243.7 243.7 222.1 — — 222.1 222.1 Liabilities and equity: Derivatives 9.7 — 5.5 4.2 9.7 19.4 — 2.9 16.5 19.4 Long-term debt (incl. current maturities) 2,801.8 — 2,916.2 — 2,916.2 2,406.0 — 2,665.7 — 2,665.7 Cumulative preferred stock 200.0 200.0 — — 200.0 200.0 203.8 — — 203.8 WPL September 30, 2018 December 31, 2017 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Derivatives $18.9 $— $9.8 $9.1 $18.9 $8.0 $— $2.1 $5.9 $8.0 Liabilities: Derivatives 12.3 — 9.2 3.1 12.3 22.3 — 5.6 16.7 22.3 Long-term debt (incl. current maturities) 1,834.5 — 2,020.9 — 2,020.9 1,833.4 — 2,147.9 — 2,147.9 |
Fair Value Measurements Using Significant Unobservable Inputs | Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions): Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended September 30 2018 2017 2018 2017 Beginning balance, July 1 ($10.7 ) $9.2 $208.3 $170.0 Total net gains (losses) included in changes in net assets (realized/unrealized) 25.7 (4.3 ) — — Transfers out of Level 3 15.6 — — — Sales (0.2 ) (0.1 ) — — Settlements (a) (6.2 ) (8.5 ) 35.4 (54.7 ) Ending balance, September 30 $24.2 ($3.7 ) $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $26.1 ($4.2 ) $— $— Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Nine Months Ended September 30 2018 2017 2018 2017 Beginning balance, January 1 ($12.2 ) $8.7 $222.1 $211.1 Total net gains (losses) included in changes in net assets (realized/unrealized) 15.7 (31.3 ) — — Transfers out of Level 3 15.6 12.2 — — Purchases 26.7 28.3 — — Sales (0.2 ) (0.3 ) — — Settlements (a) (21.4 ) (21.3 ) 21.6 (95.8 ) Ending balance, September 30 $24.2 ($3.7 ) $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $16.5 ($29.4 ) $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended September 30 2018 2017 2018 2017 Beginning balance, July 1 ($4.1 ) $17.1 $208.3 $170.0 Total net gains (losses) included in changes in net assets (realized/unrealized) 16.8 (4.4 ) — — Transfers out of Level 3 10.5 — — — Sales (0.1 ) (0.1 ) — — Settlements (a) (4.9 ) (7.3 ) 35.4 (54.7 ) Ending balance, September 30 $18.2 $5.3 $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $16.8 ($4.5 ) $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Nine Months Ended September 30 2018 2017 2018 2017 Beginning balance, January 1 ($1.4 ) $10.1 $222.1 $211.1 Total net gains (losses) included in changes in net assets (realized/unrealized) 7.6 (13.9 ) — — Transfers out of Level 3 10.5 3.1 — — Purchases 19.3 24.6 — — Sales (0.1 ) (0.2 ) — — Settlements (a) (17.7 ) (18.4 ) 21.6 (95.8 ) Ending balance, September 30 $18.2 $5.3 $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $7.9 ($12.6 ) $— $— WPL Commodity Contract Derivative Assets and (Liabilities), net Three Months Ended September 30 2018 2017 Beginning balance, July 1 ($6.6 ) ($7.9 ) Total net gains included in changes in net assets (realized/unrealized) 8.9 0.1 Transfers out of Level 3 5.1 — Sales (0.1 ) — Settlements (1.3 ) (1.2 ) Ending balance, September 30 $6.0 ($9.0 ) The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at September 30 $9.3 $0.3 WPL Commodity Contract Derivative Assets and (Liabilities), net Nine Months Ended September 30 2018 2017 Beginning balance, January 1 ($10.8 ) ($1.4 ) Total net gains (losses) included in changes in net assets (realized/unrealized) 8.1 (17.4 ) Transfers out of Level 3 5.1 9.1 Purchases 7.4 3.7 Sales (0.1 ) (0.1 ) Settlements (3.7 ) (2.9 ) Ending balance, September 30 $6.0 ($9.0 ) The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $8.6 ($16.8 ) (a) Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for doubtful accounts associated with the receivables sold and cash amounts received from the receivables sold. |
Fair Value Of Net Derivative Assets (Liabilities) | The fair value of electric, natural gas, coal and diesel fuel commodity contracts categorized as Level 3 was recognized as net derivative assets (liabilities) as follows (in millions): Alliant Energy IPL WPL Excluding FTRs FTRs Excluding FTRs FTRs Excluding FTRs FTRs September 30, 2018 $7.9 $16.3 $5.4 $12.8 $2.5 $3.5 December 31, 2017 (23.5 ) 11.3 (11.5 ) 10.1 (12.0 ) 1.2 |
IPL [Member] | |
Statement [Line Items] | |
Fair Value Measurements | Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions): Alliant Energy September 30, 2018 December 31, 2017 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $228.0 $228.0 $— $— $228.0 $— $— $— $— $— Derivatives 48.0 — 16.5 31.5 48.0 25.1 — 4.1 21.0 25.1 Deferred proceeds 243.7 — — 243.7 243.7 222.1 — — 222.1 222.1 Liabilities and equity: Derivatives 22.0 — 14.7 7.3 22.0 41.7 — 8.5 33.2 41.7 Long-term debt (incl. current maturities) 5,754.3 — 6,057.8 2.5 6,060.3 4,866.3 — 5,444.6 2.9 5,447.5 Cumulative preferred stock of IPL 200.0 200.0 — — 200.0 200.0 203.8 — — 203.8 IPL September 30, 2018 December 31, 2017 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $228.0 $228.0 $— $— $228.0 $— $— $— $— $— Derivatives 29.1 — 6.7 22.4 29.1 17.1 — 2.0 15.1 17.1 Deferred proceeds 243.7 — — 243.7 243.7 222.1 — — 222.1 222.1 Liabilities and equity: Derivatives 9.7 — 5.5 4.2 9.7 19.4 — 2.9 16.5 19.4 Long-term debt (incl. current maturities) 2,801.8 — 2,916.2 — 2,916.2 2,406.0 — 2,665.7 — 2,665.7 Cumulative preferred stock 200.0 200.0 — — 200.0 200.0 203.8 — — 203.8 WPL September 30, 2018 December 31, 2017 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Derivatives $18.9 $— $9.8 $9.1 $18.9 $8.0 $— $2.1 $5.9 $8.0 Liabilities: Derivatives 12.3 — 9.2 3.1 12.3 22.3 — 5.6 16.7 22.3 Long-term debt (incl. current maturities) 1,834.5 — 2,020.9 — 2,020.9 1,833.4 — 2,147.9 — 2,147.9 |
Fair Value Measurements Using Significant Unobservable Inputs | Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions): Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended September 30 2018 2017 2018 2017 Beginning balance, July 1 ($10.7 ) $9.2 $208.3 $170.0 Total net gains (losses) included in changes in net assets (realized/unrealized) 25.7 (4.3 ) — — Transfers out of Level 3 15.6 — — — Sales (0.2 ) (0.1 ) — — Settlements (a) (6.2 ) (8.5 ) 35.4 (54.7 ) Ending balance, September 30 $24.2 ($3.7 ) $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $26.1 ($4.2 ) $— $— Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Nine Months Ended September 30 2018 2017 2018 2017 Beginning balance, January 1 ($12.2 ) $8.7 $222.1 $211.1 Total net gains (losses) included in changes in net assets (realized/unrealized) 15.7 (31.3 ) — — Transfers out of Level 3 15.6 12.2 — — Purchases 26.7 28.3 — — Sales (0.2 ) (0.3 ) — — Settlements (a) (21.4 ) (21.3 ) 21.6 (95.8 ) Ending balance, September 30 $24.2 ($3.7 ) $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $16.5 ($29.4 ) $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended September 30 2018 2017 2018 2017 Beginning balance, July 1 ($4.1 ) $17.1 $208.3 $170.0 Total net gains (losses) included in changes in net assets (realized/unrealized) 16.8 (4.4 ) — — Transfers out of Level 3 10.5 — — — Sales (0.1 ) (0.1 ) — — Settlements (a) (4.9 ) (7.3 ) 35.4 (54.7 ) Ending balance, September 30 $18.2 $5.3 $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $16.8 ($4.5 ) $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Nine Months Ended September 30 2018 2017 2018 2017 Beginning balance, January 1 ($1.4 ) $10.1 $222.1 $211.1 Total net gains (losses) included in changes in net assets (realized/unrealized) 7.6 (13.9 ) — — Transfers out of Level 3 10.5 3.1 — — Purchases 19.3 24.6 — — Sales (0.1 ) (0.2 ) — — Settlements (a) (17.7 ) (18.4 ) 21.6 (95.8 ) Ending balance, September 30 $18.2 $5.3 $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $7.9 ($12.6 ) $— $— WPL Commodity Contract Derivative Assets and (Liabilities), net Three Months Ended September 30 2018 2017 Beginning balance, July 1 ($6.6 ) ($7.9 ) Total net gains included in changes in net assets (realized/unrealized) 8.9 0.1 Transfers out of Level 3 5.1 — Sales (0.1 ) — Settlements (1.3 ) (1.2 ) Ending balance, September 30 $6.0 ($9.0 ) The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at September 30 $9.3 $0.3 WPL Commodity Contract Derivative Assets and (Liabilities), net Nine Months Ended September 30 2018 2017 Beginning balance, January 1 ($10.8 ) ($1.4 ) Total net gains (losses) included in changes in net assets (realized/unrealized) 8.1 (17.4 ) Transfers out of Level 3 5.1 9.1 Purchases 7.4 3.7 Sales (0.1 ) (0.1 ) Settlements (3.7 ) (2.9 ) Ending balance, September 30 $6.0 ($9.0 ) The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $8.6 ($16.8 ) (a) Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for doubtful accounts associated with the receivables sold and cash amounts received from the receivables sold. |
Fair Value Of Net Derivative Assets (Liabilities) | The fair value of electric, natural gas, coal and diesel fuel commodity contracts categorized as Level 3 was recognized as net derivative assets (liabilities) as follows (in millions): Alliant Energy IPL WPL Excluding FTRs FTRs Excluding FTRs FTRs Excluding FTRs FTRs September 30, 2018 $7.9 $16.3 $5.4 $12.8 $2.5 $3.5 December 31, 2017 (23.5 ) 11.3 (11.5 ) 10.1 (12.0 ) 1.2 |
WPL [Member] | |
Statement [Line Items] | |
Fair Value Measurements | Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions): Alliant Energy September 30, 2018 December 31, 2017 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $228.0 $228.0 $— $— $228.0 $— $— $— $— $— Derivatives 48.0 — 16.5 31.5 48.0 25.1 — 4.1 21.0 25.1 Deferred proceeds 243.7 — — 243.7 243.7 222.1 — — 222.1 222.1 Liabilities and equity: Derivatives 22.0 — 14.7 7.3 22.0 41.7 — 8.5 33.2 41.7 Long-term debt (incl. current maturities) 5,754.3 — 6,057.8 2.5 6,060.3 4,866.3 — 5,444.6 2.9 5,447.5 Cumulative preferred stock of IPL 200.0 200.0 — — 200.0 200.0 203.8 — — 203.8 IPL September 30, 2018 December 31, 2017 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $228.0 $228.0 $— $— $228.0 $— $— $— $— $— Derivatives 29.1 — 6.7 22.4 29.1 17.1 — 2.0 15.1 17.1 Deferred proceeds 243.7 — — 243.7 243.7 222.1 — — 222.1 222.1 Liabilities and equity: Derivatives 9.7 — 5.5 4.2 9.7 19.4 — 2.9 16.5 19.4 Long-term debt (incl. current maturities) 2,801.8 — 2,916.2 — 2,916.2 2,406.0 — 2,665.7 — 2,665.7 Cumulative preferred stock 200.0 200.0 — — 200.0 200.0 203.8 — — 203.8 WPL September 30, 2018 December 31, 2017 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Derivatives $18.9 $— $9.8 $9.1 $18.9 $8.0 $— $2.1 $5.9 $8.0 Liabilities: Derivatives 12.3 — 9.2 3.1 12.3 22.3 — 5.6 16.7 22.3 Long-term debt (incl. current maturities) 1,834.5 — 2,020.9 — 2,020.9 1,833.4 — 2,147.9 — 2,147.9 |
Fair Value Measurements Using Significant Unobservable Inputs | Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions): Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended September 30 2018 2017 2018 2017 Beginning balance, July 1 ($10.7 ) $9.2 $208.3 $170.0 Total net gains (losses) included in changes in net assets (realized/unrealized) 25.7 (4.3 ) — — Transfers out of Level 3 15.6 — — — Sales (0.2 ) (0.1 ) — — Settlements (a) (6.2 ) (8.5 ) 35.4 (54.7 ) Ending balance, September 30 $24.2 ($3.7 ) $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $26.1 ($4.2 ) $— $— Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Nine Months Ended September 30 2018 2017 2018 2017 Beginning balance, January 1 ($12.2 ) $8.7 $222.1 $211.1 Total net gains (losses) included in changes in net assets (realized/unrealized) 15.7 (31.3 ) — — Transfers out of Level 3 15.6 12.2 — — Purchases 26.7 28.3 — — Sales (0.2 ) (0.3 ) — — Settlements (a) (21.4 ) (21.3 ) 21.6 (95.8 ) Ending balance, September 30 $24.2 ($3.7 ) $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $16.5 ($29.4 ) $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended September 30 2018 2017 2018 2017 Beginning balance, July 1 ($4.1 ) $17.1 $208.3 $170.0 Total net gains (losses) included in changes in net assets (realized/unrealized) 16.8 (4.4 ) — — Transfers out of Level 3 10.5 — — — Sales (0.1 ) (0.1 ) — — Settlements (a) (4.9 ) (7.3 ) 35.4 (54.7 ) Ending balance, September 30 $18.2 $5.3 $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $16.8 ($4.5 ) $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Nine Months Ended September 30 2018 2017 2018 2017 Beginning balance, January 1 ($1.4 ) $10.1 $222.1 $211.1 Total net gains (losses) included in changes in net assets (realized/unrealized) 7.6 (13.9 ) — — Transfers out of Level 3 10.5 3.1 — — Purchases 19.3 24.6 — — Sales (0.1 ) (0.2 ) — — Settlements (a) (17.7 ) (18.4 ) 21.6 (95.8 ) Ending balance, September 30 $18.2 $5.3 $243.7 $115.3 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $7.9 ($12.6 ) $— $— WPL Commodity Contract Derivative Assets and (Liabilities), net Three Months Ended September 30 2018 2017 Beginning balance, July 1 ($6.6 ) ($7.9 ) Total net gains included in changes in net assets (realized/unrealized) 8.9 0.1 Transfers out of Level 3 5.1 — Sales (0.1 ) — Settlements (1.3 ) (1.2 ) Ending balance, September 30 $6.0 ($9.0 ) The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at September 30 $9.3 $0.3 WPL Commodity Contract Derivative Assets and (Liabilities), net Nine Months Ended September 30 2018 2017 Beginning balance, January 1 ($10.8 ) ($1.4 ) Total net gains (losses) included in changes in net assets (realized/unrealized) 8.1 (17.4 ) Transfers out of Level 3 5.1 9.1 Purchases 7.4 3.7 Sales (0.1 ) (0.1 ) Settlements (3.7 ) (2.9 ) Ending balance, September 30 $6.0 ($9.0 ) The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 $8.6 ($16.8 ) (a) Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for doubtful accounts associated with the receivables sold and cash amounts received from the receivables sold. |
Fair Value Of Net Derivative Assets (Liabilities) | The fair value of electric, natural gas, coal and diesel fuel commodity contracts categorized as Level 3 was recognized as net derivative assets (liabilities) as follows (in millions): Alliant Energy IPL WPL Excluding FTRs FTRs Excluding FTRs FTRs Excluding FTRs FTRs September 30, 2018 $7.9 $16.3 $5.4 $12.8 $2.5 $3.5 December 31, 2017 (23.5 ) 11.3 (11.5 ) 10.1 (12.0 ) 1.2 |
Derivative Instruments (Tables)
Derivative Instruments (Tables) | 9 Months Ended |
Sep. 30, 2018 | |
Derivative Instruments [Line Items] | |
Notional Amounts Of Derivative Instruments | As of September 30, 2018 , gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands): Electricity FTRs Natural Gas Coal Diesel Fuel MWhs Years MWhs Years Dths Years Tons Years Gallons Years Alliant Energy 331 2018 16,553 2018-2019 179,275 2018-2026 11,922 2018-2021 3,906 2018-2019 IPL — — 9,220 2018-2019 83,485 2018-2026 4,849 2018-2021 — — WPL 331 2018 7,333 2018-2019 95,790 2018-2026 7,073 2018-2021 3,906 2018-2019 |
Fair Value Of Financial Instruments | The fair values of current derivative assets are included in “Other current assets,” non-current derivative assets are included in “Deferred charges and other,” current derivative liabilities are included in “Other current liabilities” and non-current derivative liabilities are included in “Other liabilities” on the balance sheets as follows (in millions): Alliant Energy IPL WPL September 30, December 31, September 30, December 31, September 30, December 31, Current derivative assets $39.7 $21.1 $26.2 $15.8 $13.5 $5.3 Non-current derivative assets 8.3 4.0 2.9 1.3 5.4 2.7 Current derivative liabilities 7.2 18.7 3.2 5.0 4.0 13.7 Non-current derivative liabilities 14.8 23.0 6.5 14.4 8.3 8.6 |
IPL [Member] | |
Derivative Instruments [Line Items] | |
Notional Amounts Of Derivative Instruments | As of September 30, 2018 , gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands): Electricity FTRs Natural Gas Coal Diesel Fuel MWhs Years MWhs Years Dths Years Tons Years Gallons Years Alliant Energy 331 2018 16,553 2018-2019 179,275 2018-2026 11,922 2018-2021 3,906 2018-2019 IPL — — 9,220 2018-2019 83,485 2018-2026 4,849 2018-2021 — — WPL 331 2018 7,333 2018-2019 95,790 2018-2026 7,073 2018-2021 3,906 2018-2019 |
Fair Value Of Financial Instruments | The fair values of current derivative assets are included in “Other current assets,” non-current derivative assets are included in “Deferred charges and other,” current derivative liabilities are included in “Other current liabilities” and non-current derivative liabilities are included in “Other liabilities” on the balance sheets as follows (in millions): Alliant Energy IPL WPL September 30, December 31, September 30, December 31, September 30, December 31, Current derivative assets $39.7 $21.1 $26.2 $15.8 $13.5 $5.3 Non-current derivative assets 8.3 4.0 2.9 1.3 5.4 2.7 Current derivative liabilities 7.2 18.7 3.2 5.0 4.0 13.7 Non-current derivative liabilities 14.8 23.0 6.5 14.4 8.3 8.6 |
WPL [Member] | |
Derivative Instruments [Line Items] | |
Notional Amounts Of Derivative Instruments | As of September 30, 2018 , gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands): Electricity FTRs Natural Gas Coal Diesel Fuel MWhs Years MWhs Years Dths Years Tons Years Gallons Years Alliant Energy 331 2018 16,553 2018-2019 179,275 2018-2026 11,922 2018-2021 3,906 2018-2019 IPL — — 9,220 2018-2019 83,485 2018-2026 4,849 2018-2021 — — WPL 331 2018 7,333 2018-2019 95,790 2018-2026 7,073 2018-2021 3,906 2018-2019 |
Fair Value Of Financial Instruments | The fair values of current derivative assets are included in “Other current assets,” non-current derivative assets are included in “Deferred charges and other,” current derivative liabilities are included in “Other current liabilities” and non-current derivative liabilities are included in “Other liabilities” on the balance sheets as follows (in millions): Alliant Energy IPL WPL September 30, December 31, September 30, December 31, September 30, December 31, Current derivative assets $39.7 $21.1 $26.2 $15.8 $13.5 $5.3 Non-current derivative assets 8.3 4.0 2.9 1.3 5.4 2.7 Current derivative liabilities 7.2 18.7 3.2 5.0 4.0 13.7 Non-current derivative liabilities 14.8 23.0 6.5 14.4 8.3 8.6 |
Commitments And Contingencies (
Commitments And Contingencies (Tables) | 9 Months Ended |
Sep. 30, 2018 | |
Commitments and Contingencies [Line Items] | |
Other Purchase Obligations | At September 30, 2018 , minimum future commitments related to these purchase obligations were as follows (in millions): Alliant Energy IPL WPL Purchased power (a) $1,089 $1,063 $26 Natural gas 921 394 527 Coal (b) 169 84 85 Other (c) 43 24 5 $2,222 $1,565 $643 (a) Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased. Alliant Energy’s and IPL’s amounts include minimum future commitments related to IPL’s purchase of capacity and the resulting energy from DAEC through December 2025. In July 2018, IPL entered into an amendment to shorten the term of the DAEC PPA by five years in exchange for a $110 million buyout payment by IPL in September 2020, which is not included in Alliant Energy’s and IPL’s amounts. The amendment to the DAEC PPA is contingent upon IUB approval of IPL’s July 2018 application regarding recovery of the buyout payment. (b) Corporate Services entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. These commitments were assigned to IPL and WPL based on information available as of September 30, 2018 regarding expected future usage, which is subject to change. (c) Includes individual commitments incurred during the normal course of business that exceeded $1 million at September 30, 2018 . |
MGP Site Estimated Future Costs And Recorded Liabilities | At September 30, 2018 , estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At September 30, 2018 , such amounts for WPL were not material. Alliant Energy IPL Range of estimated future costs $11 - $29 $9 - $25 Current and non-current environmental liabilities 16 13 |
IPL [Member] | |
Commitments and Contingencies [Line Items] | |
Other Purchase Obligations | At September 30, 2018 , minimum future commitments related to these purchase obligations were as follows (in millions): Alliant Energy IPL WPL Purchased power (a) $1,089 $1,063 $26 Natural gas 921 394 527 Coal (b) 169 84 85 Other (c) 43 24 5 $2,222 $1,565 $643 (a) Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased. Alliant Energy’s and IPL’s amounts include minimum future commitments related to IPL’s purchase of capacity and the resulting energy from DAEC through December 2025. In July 2018, IPL entered into an amendment to shorten the term of the DAEC PPA by five years in exchange for a $110 million buyout payment by IPL in September 2020, which is not included in Alliant Energy’s and IPL’s amounts. The amendment to the DAEC PPA is contingent upon IUB approval of IPL’s July 2018 application regarding recovery of the buyout payment. (b) Corporate Services entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. These commitments were assigned to IPL and WPL based on information available as of September 30, 2018 regarding expected future usage, which is subject to change. (c) Includes individual commitments incurred during the normal course of business that exceeded $1 million at September 30, 2018 . |
MGP Site Estimated Future Costs And Recorded Liabilities | At September 30, 2018 , estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At September 30, 2018 , such amounts for WPL were not material. Alliant Energy IPL Range of estimated future costs $11 - $29 $9 - $25 Current and non-current environmental liabilities 16 13 |
WPL [Member] | |
Commitments and Contingencies [Line Items] | |
Other Purchase Obligations | At September 30, 2018 , minimum future commitments related to these purchase obligations were as follows (in millions): Alliant Energy IPL WPL Purchased power (a) $1,089 $1,063 $26 Natural gas 921 394 527 Coal (b) 169 84 85 Other (c) 43 24 5 $2,222 $1,565 $643 (a) Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased. Alliant Energy’s and IPL’s amounts include minimum future commitments related to IPL’s purchase of capacity and the resulting energy from DAEC through December 2025. In July 2018, IPL entered into an amendment to shorten the term of the DAEC PPA by five years in exchange for a $110 million buyout payment by IPL in September 2020, which is not included in Alliant Energy’s and IPL’s amounts. The amendment to the DAEC PPA is contingent upon IUB approval of IPL’s July 2018 application regarding recovery of the buyout payment. (b) Corporate Services entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. These commitments were assigned to IPL and WPL based on information available as of September 30, 2018 regarding expected future usage, which is subject to change. (c) Includes individual commitments incurred during the normal course of business that exceeded $1 million at September 30, 2018 . |
Segments Of Business (Tables)
Segments Of Business (Tables) | 9 Months Ended |
Sep. 30, 2018 | |
Segment Reporting Information [Line Items] | |
Schedule Of Segments Of Business | Certain financial information relating to Alliant Energy’s business segments is as follows. Intersegment revenues were not material to Alliant Energy’s operations. ATC Holdings, Alliant Utility Non-Utility, Energy Electric Gas Other Total Parent and Other Consolidated (in millions) Three Months Ended September 30, 2018 Revenues $861.2 $44.8 $12.3 $918.3 $10.3 $928.6 Operating income (loss) 248.7 (2.0 ) 0.6 247.3 8.8 256.1 Net income attributable to Alliant Energy common shareowners 202.8 2.7 205.5 Three Months Ended September 30, 2017 Revenues $840.6 $45.8 $11.2 $897.6 $9.3 $906.9 Operating income (loss) 236.7 (1.7 ) (7.7 ) 227.3 9.0 236.3 Net income (loss) attributable to Alliant Energy common shareowners 170.2 (1.4 ) 168.8 ATC Holdings, Alliant Utility Non-Utility, Energy Electric Gas Other Total Parent and Other Consolidated (in millions) Nine Months Ended September 30, 2018 Revenues $2,296.2 $299.0 $36.2 $2,631.4 $29.6 $2,661.0 Operating income 510.2 34.9 2.9 548.0 25.0 573.0 Net income attributable to Alliant Energy common shareowners 395.0 31.8 426.8 Nine Months Ended September 30, 2017 Revenues $2,199.1 $262.7 $34.4 $2,496.2 $29.9 $2,526.1 Operating income (loss) 486.9 31.3 (6.7 ) 511.5 25.7 537.2 Amounts attributable to Alliant Energy common shareowners: Income from continuing operations, net of tax 333.8 28.3 362.1 Income from discontinued operations, net of tax — 1.4 1.4 Net income 333.8 29.7 363.5 |
IPL [Member] | |
Segment Reporting Information [Line Items] | |
Schedule Of Segments Of Business | Certain financial information relating to IPL’s business segments is as follows. Intersegment revenues were not material to IPL’s operations. Electric Gas Other Total (in millions) Three Months Ended September 30, 2018 Revenues $509.2 $26.7 $11.7 $547.6 Operating income (loss) 144.7 (3.1 ) 1.5 143.1 Earnings available for common stock 126.5 Three Months Ended September 30, 2017 Revenues $489.0 $27.4 $11.0 $527.4 Operating income (loss) 140.0 (1.8 ) (4.4 ) 133.8 Earnings available for common stock 120.4 Nine Months Ended September 30, 2018 Revenues $1,337.0 $177.0 $34.2 $1,548.2 Operating income 275.7 16.3 4.4 296.4 Earnings available for common stock 224.9 Nine Months Ended September 30, 2017 Revenues $1,217.6 $147.2 $33.3 $1,398.1 Operating income (loss) 239.2 15.4 (1.4 ) 253.2 Earnings available for common stock 200.4 |
WPL [Member] | |
Segment Reporting Information [Line Items] | |
Schedule Of Segments Of Business | Certain financial information relating to WPL’s business segments is as follows. Intersegment revenues were not material to WPL’s operations. Electric Gas Other Total (in millions) Three Months Ended September 30, 2018 Revenues $352.0 $18.1 $0.6 $370.7 Operating income (loss) 104.0 1.1 (0.9 ) 104.2 Earnings available for common stock 76.3 Three Months Ended September 30, 2017 Revenues $351.6 $18.4 $0.2 $370.2 Operating income (loss) 96.7 0.1 (3.3 ) 93.5 Earnings available for common stock 49.8 Nine Months Ended September 30, 2018 Revenues $959.2 $122.0 $2.0 $1,083.2 Operating income (loss) 234.5 18.6 (1.5 ) 251.6 Earnings available for common stock 170.1 Nine Months Ended September 30, 2017 Revenues $981.5 $115.5 $1.1 $1,098.1 Operating income (loss) 247.7 15.9 (5.3 ) 258.3 Earnings available for common stock 133.4 |
Related Parties (Tables)
Related Parties (Tables) | 9 Months Ended |
Sep. 30, 2018 | |
Related Party Transactions [Line Items] | |
Services Provided, Sales Credited And Purchases | The amounts billed for services provided, sales credited and purchases for the three and nine months ended September 30 were as follows (in millions): IPL WPL Three Months Nine Months Three Months Nine Months 2018 2017 2018 2017 2018 2017 2018 2017 Corporate Services billings $43 $48 $128 $130 $33 $37 $100 $100 Sales credited 11 8 34 15 7 6 16 8 Purchases billed 95 109 268 271 19 32 56 99 |
Net Intercompany Payables | Net intercompany payables to Corporate Services were as follows (in millions): IPL WPL September 30, 2018 December 31, 2017 September 30, 2018 December 31, 2017 Net payables to Corporate Services $109 $114 $65 $61 |
Related Amounts Billed Between Parties | The related amounts billed between the parties for the three and nine months ended September 30 were as follows (in millions): Three Months Nine Months 2018 2017 2018 2017 ATC billings to WPL $26 $26 $79 $79 WPL billings to ATC 3 2 8 8 |
IPL [Member] | |
Related Party Transactions [Line Items] | |
Services Provided, Sales Credited And Purchases | The amounts billed for services provided, sales credited and purchases for the three and nine months ended September 30 were as follows (in millions): IPL WPL Three Months Nine Months Three Months Nine Months 2018 2017 2018 2017 2018 2017 2018 2017 Corporate Services billings $43 $48 $128 $130 $33 $37 $100 $100 Sales credited 11 8 34 15 7 6 16 8 Purchases billed 95 109 268 271 19 32 56 99 |
Net Intercompany Payables | Net intercompany payables to Corporate Services were as follows (in millions): IPL WPL September 30, 2018 December 31, 2017 September 30, 2018 December 31, 2017 Net payables to Corporate Services $109 $114 $65 $61 |
WPL [Member] | |
Related Party Transactions [Line Items] | |
Services Provided, Sales Credited And Purchases | The amounts billed for services provided, sales credited and purchases for the three and nine months ended September 30 were as follows (in millions): IPL WPL Three Months Nine Months Three Months Nine Months 2018 2017 2018 2017 2018 2017 2018 2017 Corporate Services billings $43 $48 $128 $130 $33 $37 $100 $100 Sales credited 11 8 34 15 7 6 16 8 Purchases billed 95 109 268 271 19 32 56 99 |
Net Intercompany Payables | Net intercompany payables to Corporate Services were as follows (in millions): IPL WPL September 30, 2018 December 31, 2017 September 30, 2018 December 31, 2017 Net payables to Corporate Services $109 $114 $65 $61 |
Related Amounts Billed Between Parties | The related amounts billed between the parties for the three and nine months ended September 30 were as follows (in millions): Three Months Nine Months 2018 2017 2018 2017 ATC billings to WPL $26 $26 $79 $79 WPL billings to ATC 3 2 8 8 |
Summary Of Significant Accoun_3
Summary Of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended | 9 Months Ended | 12 Months Ended | ||||
Mar. 31, 2018 | Sep. 30, 2017 | Mar. 31, 2017 | Jun. 30, 2018 | Jun. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | Dec. 31, 2017 | |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] | ||||||||
Money market fund investments | $ 228 | $ 0 | ||||||
Money market fund investments interest rate, percentage | 2.00% | |||||||
Adjustment to net periodic benefit costs, percentage | 40.00% | |||||||
Income statement impact of adoption of Accounting Standards Update 2017-17 | $ 4.8 | $ 13.5 | ||||||
Cash receipts on sold receivables | $ 337.2 | 432.1 | ||||||
Net cash flows from operating activities | $ 156.3 | $ 173.5 | $ 274.4 | $ 249.8 | 442.2 | $ 451.3 | ||
IPL [Member] | ||||||||
New Accounting Pronouncements or Change in Accounting Principle [Line Items] | ||||||||
Money market fund investments | $ 228 | 0 | ||||||
Money market fund investments interest rate, percentage | 2.00% | |||||||
Adjustment to net periodic benefit costs, percentage | 40.00% | |||||||
Income statement impact of adoption of Accounting Standards Update 2017-17 | 2 | $ 5.5 | ||||||
Cash receipts on sold receivables | $ 337.2 | 432.1 | ||||||
Net cash flows from operating activities | $ 1.8 | $ 16.1 | $ 12.8 | $ 15.8 | 38.9 | $ 38.4 | ||
WPL [Member] | ||||||||
New Accounting Pronouncements or Change in Accounting Principle [Line Items] | ||||||||
Adjustment to net periodic benefit costs, percentage | 40.00% | |||||||
Income statement impact of adoption of Accounting Standards Update 2017-17 | $ 2.8 | $ 7.9 | ||||||
Net cash flows from operating activities | $ 345.5 | 361.2 | ||||||
Alliant Energy and IPL [Member] | ||||||||
New Accounting Pronouncements or Change in Accounting Principle [Line Items] | ||||||||
Cash receipts on sold receivables | $ 432.1 | $ 461.8 |
Regulatory Matters (Narrative)
Regulatory Matters (Narrative) (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | 12 Months Ended | ||||
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | Dec. 31, 2021 | Dec. 31, 2019 | Dec. 31, 2017 | |
Regulatory Matters [Line Items] | |||||||
State income tax rate | 5.30% | 13.20% | 8.80% | 14.90% | |||
Decrease in regulatory assets | $ (27.4) | $ 108.9 | |||||
Increase in regulatory liabilities | 14.7 | $ (64.8) | |||||
Regulatory assets | $ 1,694.7 | 1,694.7 | $ 1,666.7 | ||||
Refunded Federal Tax Reform benefits | 20 | 47 | |||||
Regulatory liabilities | $ 1,505.6 | $ 1,505.6 | 1,497.2 | ||||
IPL [Member] | |||||||
Regulatory Matters [Line Items] | |||||||
State income tax rate | (4.80%) | (13.20%) | (0.20%) | (9.80%) | |||
Decrease in regulatory assets | $ (14) | $ 107.8 | |||||
Increase in regulatory liabilities | 7.5 | $ (49.6) | |||||
Regulatory assets | $ 1,249.9 | 1,249.9 | 1,231.6 | ||||
Refunded Federal Tax Reform benefits | 9 | 16 | |||||
Regulatory liabilities | $ 762.6 | $ 762.6 | 755.4 | ||||
WPL [Member] | |||||||
Regulatory Matters [Line Items] | |||||||
State income tax rate | 11.80% | 31.60% | 14.20% | 31.10% | |||
Decrease in regulatory assets | $ (13.4) | $ 1.1 | |||||
Regulatory assets | $ 444.8 | 444.8 | 435.1 | ||||
Refunded Federal Tax Reform benefits | 11 | 31 | |||||
Regulatory liabilities | 743 | 743 | 741.8 | ||||
Iowa tax reform [Member] | Alliant Energy and IPL [Member] | |||||||
Regulatory Matters [Line Items] | |||||||
Decrease in regulatory assets | 33.7 | ||||||
Increase in regulatory liabilities | 7.3 | ||||||
2017 Test Year Retail Gas [Member] | IPL [Member] | |||||||
Regulatory Matters [Line Items] | |||||||
Interim rate increase, amount | $ 11 | ||||||
Interim rate increase, percent | 5.00% | ||||||
2016 Test Year Retail Electric [Member] | IPL [Member] | |||||||
Regulatory Matters [Line Items] | |||||||
Interim rate increase, amount | $ 102 | ||||||
Interim rate increase, percent | 7.00% | ||||||
Approved rate increase, amount | $ 130 | ||||||
Approved rate increase, percent | 9.00% | ||||||
Scenario, Forecast [Member] | |||||||
Regulatory Matters [Line Items] | |||||||
Recovery period, authorized | 10 years | ||||||
Scenario, Forecast [Member] | 2017 Test Year Retail Gas [Member] | IPL [Member] | |||||||
Regulatory Matters [Line Items] | |||||||
Requested rate increase, amount | $ 20 | ||||||
Requested rate increase, percent | 8.00% | ||||||
Requested rate increase, amended amount | $ 14 | ||||||
Requested rate increase, amended percent | 6.00% | ||||||
Revenue Subject to Refund [Member] | |||||||
Regulatory Matters [Line Items] | |||||||
Regulatory liabilities | $ 22 | $ 22 | |||||
Revenue Subject to Refund [Member] | IPL [Member] | |||||||
Regulatory Matters [Line Items] | |||||||
Regulatory liabilities | 19 | 19 | |||||
Revenue Subject to Refund [Member] | WPL [Member] | |||||||
Regulatory Matters [Line Items] | |||||||
Regulatory liabilities | 3 | 3 | |||||
Revenue Subject to Refund [Member] | 2017 and 2018 Test Period Retail Electric and Gas [Member] | Alliant Energy and WPL [Member] | |||||||
Regulatory Matters [Line Items] | |||||||
Regulatory liabilities | 12 | $ 12 | |||||
State [Member] | IPL [Member] | |||||||
Regulatory Matters [Line Items] | |||||||
State income tax rate | 12.00% | ||||||
State [Member] | Scenario, Forecast [Member] | IPL [Member] | |||||||
Regulatory Matters [Line Items] | |||||||
State income tax rate | 9.80% | ||||||
Net book value of M.L. Kapp [Member] | Alliant Energy and IPL [Member] | |||||||
Regulatory Matters [Line Items] | |||||||
Regulatory assets | 29 | $ 29 | |||||
Net book value of Edgewater Unit 4 [Member] | Alliant Energy and WPL [Member] | |||||||
Regulatory Matters [Line Items] | |||||||
Regulatory assets | $ 24 | $ 24 |
Regulatory Matters (Regulatory
Regulatory Matters (Regulatory Assets) (Details) - USD ($) $ in Millions | Sep. 30, 2018 | Dec. 31, 2017 |
Regulatory Assets [Line Items] | ||
Regulatory assets | $ 1,694.7 | $ 1,666.7 |
Tax-related [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 798.3 | 778.2 |
Pension and OPEB costs [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 519.8 | 548 |
Asset retirement obligations [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 111.6 | 109.3 |
EGUs retired early [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 110.4 | 63.8 |
Derivatives [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 26.3 | 45.3 |
Emission allowances [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 24.3 | 25.5 |
Other [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 104 | 96.6 |
IPL [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 1,249.9 | 1,231.6 |
IPL [Member] | Tax-related [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 762.4 | 750.5 |
IPL [Member] | Pension and OPEB costs [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 261.2 | 274.4 |
IPL [Member] | Asset retirement obligations [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 77.3 | 72.5 |
IPL [Member] | EGUs retired early [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 57.2 | 31.6 |
IPL [Member] | Derivatives [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 13.3 | 21.8 |
IPL [Member] | Emission allowances [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 24.3 | 25.5 |
IPL [Member] | Other [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 54.2 | 55.3 |
WPL [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 444.8 | 435.1 |
WPL [Member] | Tax-related [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 35.9 | 27.7 |
WPL [Member] | Pension and OPEB costs [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 258.6 | 273.6 |
WPL [Member] | Asset retirement obligations [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 34.3 | 36.8 |
WPL [Member] | EGUs retired early [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 53.2 | 32.2 |
WPL [Member] | Derivatives [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 13 | 23.5 |
WPL [Member] | Other [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | $ 49.8 | $ 41.3 |
Regulatory Matters (Regulator_2
Regulatory Matters (Regulatory Liabilities) (Details) - USD ($) $ in Millions | Sep. 30, 2018 | Dec. 31, 2017 |
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | $ 1,505.6 | $ 1,497.2 |
Tax-related [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 891.1 | 899.4 |
Cost of removal obligations [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 401 | 410 |
Electric transmission cost recovery [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 97 | 90.4 |
Commodity cost recovery [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 20.1 | 21 |
IPL's tax benefit riders [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 13 | 25 |
Other [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 83.4 | 51.4 |
IPL [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 762.6 | 755.4 |
IPL [Member] | Tax-related [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 389.9 | 399.5 |
IPL [Member] | Cost of removal obligations [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 274 | 274.5 |
IPL [Member] | Electric transmission cost recovery [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 37.9 | 26.4 |
IPL [Member] | Commodity cost recovery [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 13.6 | 14.6 |
IPL [Member] | IPL's tax benefit riders [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 13 | 25 |
IPL [Member] | Other [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 34.2 | 15.4 |
WPL [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 743 | 741.8 |
WPL [Member] | Tax-related [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 501.2 | 499.9 |
WPL [Member] | Cost of removal obligations [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 127 | 135.5 |
WPL [Member] | Electric transmission cost recovery [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 59.1 | 64 |
WPL [Member] | Commodity cost recovery [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 6.5 | 6.4 |
WPL [Member] | Other [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | $ 49.2 | $ 36 |
Property, Plant and Equipment (
Property, Plant and Equipment (Narrative) (Details) $ in Millions | 3 Months Ended | 9 Months Ended | 12 Months Ended | |||
Sep. 30, 2018USD ($) | Sep. 30, 2017USD ($) | Sep. 30, 2018USD ($)MW | Sep. 30, 2017USD ($) | Dec. 31, 2020MW | Apr. 30, 2018USD ($) | |
Property, Plant and Equipment [Line Items] | ||||||
Allowance for funds used during construction | $ 18.8 | $ 9.6 | $ 51.8 | $ 36.7 | ||
WPL [Member] | ||||||
Property, Plant and Equipment [Line Items] | ||||||
Allowance for funds used during construction | 7.8 | 4.9 | 23.5 | 11.6 | ||
IPL [Member] | ||||||
Property, Plant and Equipment [Line Items] | ||||||
Allowance for funds used during construction | 11 | $ 4.7 | $ 28.3 | $ 25.1 | ||
West Riverside Energy Center [Member] | WPL [Member] | ||||||
Property, Plant and Equipment [Line Items] | ||||||
Fossil-fueled EGU capacity (in megawatts) | MW | 730 | |||||
Fossil-fueled EGU capacity acquired by electric cooperatives (in megawatts) | MW | 60 | |||||
Wholesale power supply agreement, term of extension | 4 years | |||||
Wholesale power supply agreement, term of notice requirement | 5 years | |||||
West Riverside Energy Center [Member] | Alliant Energy and WPL [Member] | ||||||
Property, Plant and Equipment [Line Items] | ||||||
Construction work in progress | 438 | $ 438 | ||||
Allowance for funds used during construction | $ 35 | |||||
Expansion of Wind Generation [Member] | ||||||
Property, Plant and Equipment [Line Items] | ||||||
Electric capacity of wind farm (in megawatts) | MW | 129 | |||||
Expansion of Wind Generation [Member] | WPL [Member] | ||||||
Property, Plant and Equipment [Line Items] | ||||||
Electric capacity of wind farm (in megawatts) | MW | 55 | |||||
Estimated fair value of net assets acquired | $ 74 | |||||
Expansion of Wind Generation [Member] | Alliant Energy and IPL [Member] | ||||||
Property, Plant and Equipment [Line Items] | ||||||
Construction work in progress | $ 645 | $ 645 | ||||
Allowance for funds used during construction | $ 33 | |||||
Scenario, Forecast [Member] | Expansion of Wind Generation [Member] | IPL [Member] | ||||||
Property, Plant and Equipment [Line Items] | ||||||
Electric capacity of wind farm (in megawatts) | MW | 1,000 |
Property, Plant and Equipment_2
Property, Plant and Equipment (Estimated Fair Value of Assets Purchased and Liabilities Assumed) (Details) - Expansion of Wind Generation [Member] - WPL [Member] $ in Millions | Apr. 30, 2018USD ($) |
Property, Plant and Equipment [Line Items] | |
Estimated fair value of property, plant and equipment, net purchased | $ 81 |
Estimated fair value of liabilities assumed | 7 |
Estimated fair value of net assets acquired | $ 74 |
Receivables (Narrative) (Detail
Receivables (Narrative) (Details) - IPL [Member] $ in Millions | Sep. 30, 2018USD ($) |
Receivables Sold [Member] | |
Receivables [Line Items] | |
Available capacity | $ 109 |
Outstanding receivables past due | 35.8 |
Minimum [Member] | |
Receivables [Line Items] | |
Limit on cash proceeds | 90 |
Maximum [Member] | |
Receivables [Line Items] | |
Limit on cash proceeds | $ 110 |
Receivables (Maximum And Averag
Receivables (Maximum And Average Outstanding Cash Proceeds) (Details) - IPL [Member] - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | ||
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | |
Receivables [Line Items] | ||||
Outstanding aggregate cash proceeds (based on daily outstanding balances) | $ 36.4 | $ 66.2 | $ 49.8 | $ 58.7 |
Maximum [Member] | ||||
Receivables [Line Items] | ||||
Outstanding aggregate cash proceeds (based on daily outstanding balances) | $ 110 | $ 112 | $ 116 | $ 112 |
Receivables (Receivables Sold U
Receivables (Receivables Sold Under The Agreement) (Details) - USD ($) $ in Millions | Sep. 30, 2018 | Dec. 31, 2017 |
Receivables [Line Items] | ||
Fair value of deferred proceeds | $ 243.7 | $ 222.1 |
IPL [Member] | ||
Receivables [Line Items] | ||
Fair value of deferred proceeds | 243.7 | 222.1 |
Receivables Sold [Member] | IPL [Member] | ||
Receivables [Line Items] | ||
Customer accounts receivable | 179 | 133.8 |
Unbilled utility revenues | 78.2 | 112.7 |
Other receivables | 0.1 | 0.3 |
Receivables sold to third party | 257.3 | 246.8 |
Less: cash proceeds | 1 | 12 |
Deferred proceeds | 256.3 | 234.8 |
Less: allowance for doubtful accounts | 12.6 | 12.7 |
Fair value of deferred proceeds | $ 243.7 | $ 222.1 |
Receivables (Additional Attribu
Receivables (Additional Attributes Of Receivables Sold Under The Agreement) (Details) - IPL [Member] - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | ||
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | |
Receivables [Line Items] | ||||
Collections | $ 549.5 | $ 347.9 | $ 1,550.2 | $ 1,283.2 |
Write-offs, net of recoveries | $ 4.9 | $ 3.5 | $ 12.9 | $ 10.4 |
Investments (Narrative) (Detail
Investments (Narrative) (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended | 9 Months Ended | ||
Sep. 30, 2018 | Sep. 30, 2017 | Jun. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | |
Schedule of Investments [Line Items] | |||||
Equity (income) loss from unconsolidated investments, net | $ (9.8) | $ (10.1) | $ (41.6) | $ (32.9) | |
Non-utility wind farm In Oklahoma [Member] | |||||
Schedule of Investments [Line Items] | |||||
Equity (income) loss from unconsolidated investments, net | $ 0.1 | $ 0.2 | $ 0 | $ (14.5) | $ 0.2 |
Investments (Unconsolidated Equ
Investments (Unconsolidated Equity Investments) (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended | 9 Months Ended | ||
Sep. 30, 2018 | Sep. 30, 2017 | Jun. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | |
Schedule of Investments [Line Items] | |||||
Equity (income) loss from unconsolidated investments, net | $ (9.8) | $ (10.1) | $ (41.6) | $ (32.9) | |
ATC Holdings [Member] | |||||
Schedule of Investments [Line Items] | |||||
Equity (income) loss from unconsolidated investments, net | (8.9) | (10.1) | (25.4) | (32.7) | |
Non-utility wind farm In Oklahoma [Member] | |||||
Schedule of Investments [Line Items] | |||||
Equity (income) loss from unconsolidated investments, net | 0.1 | 0.2 | $ 0 | (14.5) | 0.2 |
Other [Member] | |||||
Schedule of Investments [Line Items] | |||||
Equity (income) loss from unconsolidated investments, net | $ (1) | $ (0.2) | $ (1.7) | $ (0.4) |
Common Equity (Narrative) (Deta
Common Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions | 3 Months Ended | 9 Months Ended | 12 Months Ended | ||
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | Dec. 31, 2018 | |
Common Equity [Line Items] | |||||
Dividends declared per common share (in dollars per share) | $ 0.335 | $ 0.315 | $ 1.005 | $ 0.945 | |
Proceeds from issuance of common stock, net | $ 191.3 | $ 143.2 | |||
IPL [Member] | |||||
Common Equity [Line Items] | |||||
Comprehensive income | $ 0 | $ 0 | 0 | 0 | |
WPL [Member] | |||||
Common Equity [Line Items] | |||||
Comprehensive income | $ 0 | $ 0 | $ 0 | $ 0 | |
At The Market Offering Program [Member] | |||||
Common Equity [Line Items] | |||||
Common stock issued during the period, At-the-market offering program (in shares) | 4,171,013 | ||||
Proceeds from issuance of common stock, net | $ 173 | ||||
Fees and commissions from issuance of common stock | $ 2 | ||||
Scenario, Forecast [Member] | At The Market Offering Program [Member] | |||||
Common Equity [Line Items] | |||||
Maximum aggregate gross sales price of common stock that can be offered and sold | $ 175 |
Common Equity (Common Share Act
Common Equity (Common Share Activity) (Details) | 9 Months Ended |
Sep. 30, 2018shares | |
Common Stock Oustanding [Roll Forward] | |
Shares outstanding, January 1, 2018 (in shares) | 231,348,646 |
Shareowner Direct Plan issuances (in shares) | 450,133 |
Equity-based compensation plans (in shares) | 5,078 |
Other (in shares) | (38,423) |
Shares outstanding, September 30, 2018 (in shares) | 235,936,447 |
At The Market Offering Program [Member] | |
Common Stock Oustanding [Roll Forward] | |
At-the-market offering program (in shares) | 4,171,013 |
Debt (Narrative) (Details)
Debt (Narrative) (Details) - USD ($) $ in Millions | 1 Months Ended | |||
Oct. 31, 2018 | Sep. 30, 2018 | Jun. 30, 2018 | Apr. 30, 2018 | |
Term Loan Credit Agreement [Member] | Short-term loan credit agreement through 2018 [Member] | Alliant Energy Finance LLC [Member] | ||||
Debt [Line Items] | ||||
Retirement of debt | $ 95 | |||
Term Loan Credit Agreement [Member] | Term loan credit agreement through April 2020 [Member] | Alliant Energy Finance LLC [Member] | ||||
Debt [Line Items] | ||||
Proceeds from issuance of long-term debt | $ 300 | |||
Interest rate, percent | 2.80% | |||
Term Loan Credit Agreement [Member] | Term loan credit agreement through 2018 [Member] | Alliant Energy Finance LLC [Member] | ||||
Debt [Line Items] | ||||
Retirement of debt | 500 | |||
Senior Notes [Member] | 3.75% senior notes due 2023 [Member] | Alliant Energy Finance LLC [Member] | ||||
Debt [Line Items] | ||||
Proceeds from issuance of long-term debt | 400 | |||
Interest rate, percent | 3.75% | |||
Senior Notes [Member] | 4.25% senior notes due 2028 [Member] | Alliant Energy Finance LLC [Member] | ||||
Debt [Line Items] | ||||
Proceeds from issuance of long-term debt | $ 300 | |||
Interest rate, percent | 4.25% | |||
Senior Debentures [Member] | 4.1% senior debentures due 2028 [Member] | IPL [Member] | ||||
Debt [Line Items] | ||||
Proceeds from issuance of long-term debt | $ 500 | |||
Interest rate, percent | 4.10% | |||
Senior Debentures [Member] | 5.875% senior debentures due 2018 [Member] | IPL [Member] | ||||
Debt [Line Items] | ||||
Retirement of debt | $ 100 | |||
Interest rate, percent | 5.875% | |||
Senior Debentures [Member] | 7.25% senior debentures due 2018 [Member] | IPL [Member] | ||||
Debt [Line Items] | ||||
Interest rate, percent | 7.25% | |||
Senior Debentures [Member] | Subsequent Event [Member] | 7.25% senior debentures due 2018 [Member] | IPL [Member] | ||||
Debt [Line Items] | ||||
Retirement of debt | $ 250 |
Revenues Revenue (Disaggregatio
Revenues Revenue (Disaggregation of Revenues) (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | ||
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | |
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | $ 928.6 | $ 906.9 | $ 2,661 | $ 2,526.1 |
Electric [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 861.2 | 840.6 | 2,296.2 | 2,199.1 |
Electric [Member] | Retail - residential [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 312.9 | 296.4 | 820.6 | 766.9 |
Electric [Member] | Retail - commercial [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 215.4 | 205.9 | 561.7 | 537.3 |
Electric [Member] | Retail - industrial [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 247.8 | 243.4 | 675.1 | 646.2 |
Electric [Member] | Wholesale [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 50 | 63.5 | 146.9 | 186.3 |
Electric [Member] | Other [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 35.1 | 31.4 | 91.9 | 62.4 |
Gas [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 44.8 | 45.8 | 299 | 262.7 |
Gas [Member] | Retail - residential [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 21.8 | 21.5 | 170.1 | 145.1 |
Gas [Member] | Retail - commercial [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 11 | 12.9 | 87.3 | 81.4 |
Gas [Member] | Retail - industrial [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 3 | 3 | 11.4 | 10.4 |
Gas [Member] | Other [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 9 | 8.4 | 30.2 | 25.8 |
Other Utility [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 12.3 | 11.2 | 36.2 | 34.4 |
Other Utility [Member] | Steam [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 8.7 | 8.3 | 26.5 | 25.3 |
Other Utility [Member] | Other [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 3.6 | 2.9 | 9.7 | 9.1 |
Non-utility and Other [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 10.3 | 9.3 | 29.6 | 29.9 |
Non-utility and Other [Member] | Transportation and other [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 10.3 | 9.3 | 29.6 | 29.9 |
IPL [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 547.6 | 527.4 | 1,548.2 | 1,398.1 |
IPL [Member] | Electric [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 509.2 | 489 | 1,337 | 1,217.6 |
IPL [Member] | Electric [Member] | Retail - residential [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 180.1 | 168.5 | 461.6 | 414.2 |
IPL [Member] | Electric [Member] | Retail - commercial [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 146 | 137.5 | 371.8 | 340.6 |
IPL [Member] | Electric [Member] | Retail - industrial [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 141.4 | 137.3 | 385 | 350.7 |
IPL [Member] | Electric [Member] | Wholesale [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 18.2 | 26.7 | 56.4 | 71.3 |
IPL [Member] | Electric [Member] | Other [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 23.5 | 19 | 62.2 | 40.8 |
IPL [Member] | Gas [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 26.7 | 27.4 | 177 | 147.2 |
IPL [Member] | Gas [Member] | Retail - residential [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 12.6 | 12 | 100.9 | 78.7 |
IPL [Member] | Gas [Member] | Retail - commercial [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 6.4 | 7.8 | 49.8 | 44.4 |
IPL [Member] | Gas [Member] | Retail - industrial [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 2 | 2.2 | 6.1 | 6.8 |
IPL [Member] | Gas [Member] | Other [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 5.7 | 5.4 | 20.2 | 17.3 |
IPL [Member] | Other Utility [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 11.7 | 11 | 34.2 | 33.3 |
IPL [Member] | Other Utility [Member] | Steam [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 8.7 | 8.3 | 26.5 | 25.3 |
IPL [Member] | Other Utility [Member] | Other [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 3 | 2.7 | 7.7 | 8 |
WPL [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 370.7 | 370.2 | 1,083.2 | 1,098.1 |
WPL [Member] | Electric [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 352 | 351.6 | 959.2 | 981.5 |
WPL [Member] | Electric [Member] | Retail - residential [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 132.8 | 127.9 | 359 | 352.7 |
WPL [Member] | Electric [Member] | Retail - commercial [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 69.4 | 68.4 | 189.9 | 196.7 |
WPL [Member] | Electric [Member] | Retail - industrial [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 106.4 | 106.1 | 290.1 | 295.5 |
WPL [Member] | Electric [Member] | Wholesale [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 31.8 | 36.8 | 90.5 | 115 |
WPL [Member] | Electric [Member] | Other [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 11.6 | 12.4 | 29.7 | 21.6 |
WPL [Member] | Gas [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 18.1 | 18.4 | 122 | 115.5 |
WPL [Member] | Gas [Member] | Retail - residential [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 9.2 | 9.5 | 69.2 | 66.4 |
WPL [Member] | Gas [Member] | Retail - commercial [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 4.6 | 5.1 | 37.5 | 37 |
WPL [Member] | Gas [Member] | Retail - industrial [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 1 | 0.8 | 5.3 | 3.6 |
WPL [Member] | Gas [Member] | Other [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 3.3 | 3 | 10 | 8.5 |
WPL [Member] | Other Utility [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | 0.6 | 0.2 | 2 | 1.1 |
WPL [Member] | Other Utility [Member] | Other [Member] | ||||
Disaggregation of Revenue [Line Items] | ||||
Revenue from contracts with customers | $ 0.6 | $ 0.2 | $ 2 | $ 1.1 |
Debt (Credit Facilities) (Detai
Debt (Credit Facilities) (Details) - USD ($) $ in Millions | Sep. 30, 2018 | Dec. 31, 2017 |
Debt [Line Items] | ||
Commercial paper outstanding | $ 136.8 | $ 320.2 |
Commercial paper weighted average interest rates | 2.40% | |
Available credit facility capacity | $ 863.2 | |
IPL [Member] | ||
Debt [Line Items] | ||
Commercial paper outstanding | 0 | |
Available credit facility capacity | 250 | |
WPL [Member] | ||
Debt [Line Items] | ||
Commercial paper outstanding | $ 38.4 | $ 25 |
Commercial paper weighted average interest rates | 2.20% | |
Available credit facility capacity | $ 311.6 |
Debt (Other Short-Term Borrowin
Debt (Other Short-Term Borrowings) (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | ||
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | |
Debt [Line Items] | ||||
Maximum amount outstanding (based on daily outstanding balances) | $ 153.3 | $ 424.4 | $ 446.5 | $ 424.4 |
Average amount outstanding (based on daily outstanding balances) | $ 80.8 | $ 386.2 | $ 207.6 | $ 323.9 |
Weighted average interest rates | 2.20% | 1.30% | 2.10% | 1.10% |
IPL [Member] | ||||
Debt [Line Items] | ||||
Maximum amount outstanding (based on daily outstanding balances) | $ 0 | $ 20 | $ 31.4 | $ 20 |
Average amount outstanding (based on daily outstanding balances) | 0 | $ 0.4 | $ 1.7 | $ 0.5 |
Weighted average interest rates | 1.40% | 2.30% | 1.20% | |
WPL [Member] | ||||
Debt [Line Items] | ||||
Maximum amount outstanding (based on daily outstanding balances) | 75.4 | $ 271.2 | $ 109.4 | $ 271.2 |
Average amount outstanding (based on daily outstanding balances) | $ 23.1 | $ 217 | $ 26.6 | $ 144.2 |
Weighted average interest rates | 2.00% | 1.10% | 1.90% | 1.00% |
Income Taxes (Narrative) (Detai
Income Taxes (Narrative) (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended |
Sep. 30, 2018 | Sep. 30, 2018 | |
Income Taxes [Line Items] | ||
Income tax benefit, Federal Tax Reform | $ 5.6 | |
Increase in deferred tax liabilities | $ 96.8 | |
IPL [Member] | ||
Income Taxes [Line Items] | ||
Income tax benefit, Federal Tax Reform | 1.1 | |
Increase in deferred tax liabilities | 22.3 | |
WPL [Member] | ||
Income Taxes [Line Items] | ||
Income tax benefit, Federal Tax Reform | $ 5.5 | |
Increase in deferred tax liabilities | $ 57.2 |
Income Taxes (Schedule Of Effec
Income Taxes (Schedule Of Effective Income Tax Rates) (Details) | 3 Months Ended | 9 Months Ended | ||
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | |
Effective Tax Rate [Line Items] | ||||
Statutory federal income tax rate | 21.00% | 35.00% | 21.00% | 35.00% |
State income taxes, net of federal benefits | 6.90% | 5.70% | 6.90% | 5.60% |
Effect of rate-making on property-related differences | (6.30%) | (10.10%) | (6.70%) | (9.10%) |
Production tax credits | (5.40%) | (6.20%) | (5.40%) | (6.00%) |
Adjustment for prior period taxes | (5.70%) | (2.00%) | (2.60%) | (1.30%) |
IPL's tax benefit riders | (2.30%) | (8.30%) | (2.20%) | (8.10%) |
Federal Tax Reform adjustments | (2.50%) | 0.00% | (1.20%) | 0.00% |
Other items, net | (0.40%) | (0.90%) | (1.00%) | (1.20%) |
Overall income tax rate | 5.30% | 13.20% | 8.80% | 14.90% |
IPL [Member] | ||||
Effective Tax Rate [Line Items] | ||||
Statutory federal income tax rate | 21.00% | 35.00% | 21.00% | 35.00% |
State income taxes, net of federal benefits | 7.70% | 6.50% | 7.70% | 6.50% |
Effect of rate-making on property-related differences | (11.50%) | (22.60%) | (12.00%) | (20.60%) |
Production tax credits | (5.50%) | (7.00%) | (5.40%) | (6.80%) |
Adjustment for prior period taxes | (10.20%) | (3.50%) | (5.40%) | (3.30%) |
IPL's tax benefit riders | (4.80%) | (20.90%) | (4.60%) | (20.10%) |
Federal Tax Reform adjustments | (0.90%) | 0.00% | (0.50%) | 0.00% |
Other items, net | (0.60%) | (0.70%) | (1.00%) | (0.50%) |
Overall income tax rate | (4.80%) | (13.20%) | (0.20%) | (9.80%) |
WPL [Member] | ||||
Effective Tax Rate [Line Items] | ||||
Statutory federal income tax rate | 21.00% | 35.00% | 21.00% | 35.00% |
State income taxes, net of federal benefits | 6.20% | 5.20% | 6.20% | 5.10% |
Effect of rate-making on property-related differences | (2.10%) | (1.90%) | (2.30%) | (1.80%) |
Production tax credits | (6.40%) | (7.00%) | (6.60%) | (7.00%) |
Adjustment for prior period taxes | (0.00%) | 0.80% | (0.00%) | 0.30% |
Federal Tax Reform adjustments | (6.40%) | 0.00% | (2.80%) | 0.00% |
Other items, net | (0.50%) | (0.50%) | (1.30%) | (0.50%) |
Overall income tax rate | 11.80% | 31.60% | 14.20% | 31.10% |
Income Taxes (Summary Of Tax Cr
Income Taxes (Summary Of Tax Credit Carryforwards) (Details) $ in Millions | Sep. 30, 2018USD ($) |
Federal [Member] | |
Carryforwards [Line Items] | |
Net operating losses, carryforward amount | $ 804 |
Tax credits, carryforward amount | 290 |
Federal [Member] | IPL [Member] | |
Carryforwards [Line Items] | |
Net operating losses, carryforward amount | 563 |
Tax credits, carryforward amount | 129 |
Federal [Member] | WPL [Member] | |
Carryforwards [Line Items] | |
Net operating losses, carryforward amount | 144 |
Tax credits, carryforward amount | 143 |
State [Member] | |
Carryforwards [Line Items] | |
Net operating losses, carryforward amount | 765 |
State [Member] | IPL [Member] | |
Carryforwards [Line Items] | |
Net operating losses, carryforward amount | 13 |
State [Member] | WPL [Member] | |
Carryforwards [Line Items] | |
Net operating losses, carryforward amount | $ 2 |
Benefit Plans (Narrative) (Deta
Benefit Plans (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions | 9 Months Ended | |
Sep. 30, 2018 | Sep. 28, 2018 | |
Defined Benefit Plan Disclosure [Line Items] | ||
Unrecognized compensation cost | $ 8.3 | |
Alliant Energy common stock closing price on September 28, 2018 (in dollars per share) | $ 42.57 | |
Minimum [Member] | ||
Defined Benefit Plan Disclosure [Line Items] | ||
Unrecognized compensation cost recognized over a weighted average period | 1 year | |
Maximum [Member] | ||
Defined Benefit Plan Disclosure [Line Items] | ||
Unrecognized compensation cost recognized over a weighted average period | 2 years | |
IPL [Member] | ||
Defined Benefit Plan Disclosure [Line Items] | ||
Unrecognized compensation cost | $ 4.6 | |
WPL [Member] | ||
Defined Benefit Plan Disclosure [Line Items] | ||
Unrecognized compensation cost | $ 3.5 |
Benefit Plans (Defined Benefit
Benefit Plans (Defined Benefit Pension And Other Postretirement Benefits Plans) (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | |||
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | ||
Defined benefit pension plans [Member] | |||||
Defined Benefit Plan Disclosure [Line Items] | |||||
Service cost | $ 3.1 | $ 3.1 | $ 9.1 | $ 9.3 | |
Interest cost | 11.7 | 12.7 | 35.1 | 38.3 | |
Expected return on plan assets | (17.4) | (16.3) | (52.3) | (49.1) | |
Amortization of prior service cost (credit) | (0.2) | (0.1) | (0.5) | (0.3) | |
Amortization of actuarial loss | 8.8 | 9.4 | 26.4 | 28.2 | |
Settlement losses | [1] | 0 | 0.9 | 0 | 0.9 |
Total | 6 | 9.7 | 17.8 | 27.3 | |
OPEB Plans [Member] | |||||
Defined Benefit Plan Disclosure [Line Items] | |||||
Service cost | 1 | 1.2 | 3.1 | 3.7 | |
Interest cost | 2 | 2.2 | 5.8 | 6.5 | |
Expected return on plan assets | (1.5) | (1.5) | (4.5) | (4.6) | |
Amortization of prior service cost (credit) | 0 | (0.1) | (0.1) | (0.2) | |
Amortization of actuarial loss | 0.8 | 1 | 2.5 | 2.9 | |
Settlement losses | [1] | 0 | 0 | 0 | 0 |
Total | 2.3 | 2.8 | 6.8 | 8.3 | |
IPL [Member] | Defined benefit pension plans [Member] | |||||
Defined Benefit Plan Disclosure [Line Items] | |||||
Service cost | 1.8 | 1.8 | 5.5 | 5.5 | |
Interest cost | 5.3 | 5.9 | 16 | 17.6 | |
Expected return on plan assets | (8.1) | (7.7) | (24.4) | (23.1) | |
Amortization of prior service cost (credit) | 0 | 0 | (0.1) | (0.1) | |
Amortization of actuarial loss | 3.7 | 4 | 11.2 | 12.1 | |
Total | 2.7 | 4 | 8.2 | 12 | |
IPL [Member] | OPEB Plans [Member] | |||||
Defined Benefit Plan Disclosure [Line Items] | |||||
Service cost | 0.4 | 0.5 | 1.3 | 1.6 | |
Interest cost | 0.7 | 0.8 | 2.3 | 2.6 | |
Expected return on plan assets | (1.1) | (1) | (3.3) | (3.2) | |
Amortization of prior service cost (credit) | 0 | 0 | 0 | 0 | |
Amortization of actuarial loss | 0.4 | 0.5 | 1 | 1.5 | |
Total | 0.4 | 0.8 | 1.3 | 2.5 | |
WPL [Member] | Defined benefit pension plans [Member] | |||||
Defined Benefit Plan Disclosure [Line Items] | |||||
Service cost | 1.1 | 1.2 | 3.3 | 3.6 | |
Interest cost | 5 | 5.5 | 15.1 | 16.4 | |
Expected return on plan assets | (7.6) | (7.2) | (22.8) | (21.4) | |
Amortization of prior service cost (credit) | 0 | 0.1 | (0.1) | 0.1 | |
Amortization of actuarial loss | 4.3 | 4.6 | 12.9 | 13.9 | |
Total | 2.8 | 4.2 | 8.4 | 12.6 | |
WPL [Member] | OPEB Plans [Member] | |||||
Defined Benefit Plan Disclosure [Line Items] | |||||
Service cost | 0.4 | 0.5 | 1.2 | 1.4 | |
Interest cost | 0.8 | 0.9 | 2.3 | 2.6 | |
Expected return on plan assets | (0.2) | (0.2) | (0.5) | (0.6) | |
Amortization of prior service cost (credit) | 0 | (0.1) | (0.1) | (0.2) | |
Amortization of actuarial loss | 0.5 | 0.4 | 1.5 | 1.2 | |
Total | $ 1.5 | $ 1.5 | $ 4.4 | $ 4.4 | |
[1] | Settlement losses related to payments made to retired executives of Alliant Energy. |
Benefit Plans (Recognized Compe
Benefit Plans (Recognized Compensation Expense And Income Tax Benefits) (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | ||
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | |
Compensation expense | $ 4.2 | $ 5.1 | $ 12.6 | $ 9.9 |
Income tax benefits | 1.2 | 2.1 | 3.6 | 4 |
IPL [Member] | ||||
Compensation expense | 2.4 | 2.8 | 7 | 5.4 |
Income tax benefits | 0.7 | 1.1 | 2.1 | 2.2 |
WPL [Member] | ||||
Compensation expense | 1.7 | 2.1 | 5.1 | 4.1 |
Income tax benefits | $ 0.5 | $ 0.9 | $ 1.4 | $ 1.7 |
Benefit Plans (Summary Of Perfo
Benefit Plans (Summary Of Performance Shares and Performance Units Activity) (Details) $ in Millions | 9 Months Ended |
Sep. 30, 2018USD ($)shares | |
Performance Shares [Member] | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward] | |
Nonvested, January 1 (in shares/awards) | 223,511 |
Granted (in shares/awards) | 74,163 |
Vested (in shares/awards) | (90,806) |
Forfeited (in shares/awards) | (905) |
Nonvested, September 30 (in shares/awards) | 205,963 |
Performance Units [Member] | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward] | |
Nonvested, January 1 (in shares/awards) | 71,737 |
Granted (in shares/awards) | 19,840 |
Vested (in shares/awards) | (31,910) |
Forfeited (in shares/awards) | (1,906) |
Nonvested, September 30 (in shares/awards) | 57,761 |
2015 Grant [Member] | Performance Shares [Member] | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward] | |
Vested (in shares/awards) | (90,806) |
Vested percentage of the target | 137.50% |
Aggregate payout value | $ | $ 5.3 |
Payout - cash | $ | $ 4.9 |
Payout - common stock shares issued (in shares) | 5,078 |
2015 Grant [Member] | Performance Units [Member] | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward] | |
Vested (in shares/awards) | (31,910) |
Vested percentage of the target | 137.50% |
Aggregate payout value | $ | $ 1.4 |
Payout - cash | $ | $ 1.4 |
Benefit Plans (Fair Values Of N
Benefit Plans (Fair Values Of Nonvested Performance Shares And Performance Units) (Details) - $ / shares | 9 Months Ended | |
Sep. 30, 2018 | Dec. 31, 2017 | |
Performance Shares [Member] | ||
Defined Benefit Plan Disclosure [Line Items] | ||
Nonvested awards at target (in shares/awards) | 205,963 | 223,511 |
Performance Units [Member] | ||
Defined Benefit Plan Disclosure [Line Items] | ||
Nonvested awards at target (in shares/awards) | 57,761 | 71,737 |
2018 Grant [Member] | Performance Shares [Member] | ||
Defined Benefit Plan Disclosure [Line Items] | ||
Nonvested awards at target (in shares/awards) | 73,258 | |
Estimated payout percentage based on performance criteria | 85.00% | |
Fair values of each nonvested award (in dollars per share) | $ 36.18 | |
2018 Grant [Member] | Performance Units [Member] | ||
Defined Benefit Plan Disclosure [Line Items] | ||
Nonvested awards at target (in shares/awards) | 19,196 | |
Estimated payout percentage based on performance criteria | 85.00% | |
Fair values of each nonvested award (in dollars per share) | $ 36.18 | |
2017 Grant [Member] | Performance Shares [Member] | ||
Defined Benefit Plan Disclosure [Line Items] | ||
Nonvested awards at target (in shares/awards) | 65,350 | |
Estimated payout percentage based on performance criteria | 105.00% | |
Fair values of each nonvested award (in dollars per share) | $ 44.70 | |
2017 Grant [Member] | Performance Units [Member] | ||
Defined Benefit Plan Disclosure [Line Items] | ||
Nonvested awards at target (in shares/awards) | 18,062 | |
Estimated payout percentage based on performance criteria | 105.00% | |
Fair values of each nonvested award (in dollars per share) | $ 44.70 | |
2016 Grant [Member] | Performance Shares [Member] | ||
Defined Benefit Plan Disclosure [Line Items] | ||
Nonvested awards at target (in shares/awards) | 67,355 | |
Estimated payout percentage based on performance criteria | 143.00% | |
Fair values of each nonvested award (in dollars per share) | $ 60.88 | |
2016 Grant [Member] | Performance Units [Member] | ||
Defined Benefit Plan Disclosure [Line Items] | ||
Nonvested awards at target (in shares/awards) | 20,503 | |
Estimated payout percentage based on performance criteria | 143.00% | |
Fair values of each nonvested award (in dollars per share) | $ 60.88 |
Benefit Plans (Summary Of Restr
Benefit Plans (Summary Of Restricted Stock Units Activity) (Details) | 9 Months Ended |
Sep. 30, 2018$ / sharesshares | |
Performance Restricted Stock Unit [Member] | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward] | |
Nonvested, January 1 (in shares/awards) | 132,705 |
Nonvested, January 1, weighted average grant date fair value (in dollars per share) | $ / shares | $ 36.50 |
Granted (in shares/awards) | 74,163 |
Granted, weighted average grant date fair value (in dollars per share) | $ / shares | $ 38.60 |
Forfeited (in shares/awards) | (905) |
Forfeited, weighted average grant date fair value (in dollars per share) | $ / shares | $ 38.60 |
Nonvested, September 30 (in shares/awards) | 205,963 |
Nonvested, September 30, weighted average grant date fair value (in dollars per share) | $ / shares | $ 37.25 |
Restricted Stock Units [Member] | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward] | |
Nonvested, January 1 (in shares/awards) | 113,749 |
Granted (in shares/awards) | 63,568 |
Forfeited (in shares/awards) | (775) |
Nonvested, September 30 (in shares/awards) | 176,542 |
Fair Value Measurements (Fair V
Fair Value Measurements (Fair Value Measurements) (Details) - USD ($) $ in Millions | Sep. 30, 2018 | Dec. 31, 2017 |
Assets: | ||
Money market fund investments | $ 228 | $ 0 |
Deferred proceeds | 243.7 | 222.1 |
Liabilities and Equity: | ||
Long-term debt (incl. current maturities) | 6,060.3 | 5,447.5 |
Cumulative preferred stock of IPL | 200 | 203.8 |
IPL [Member] | ||
Assets: | ||
Money market fund investments | 228 | 0 |
Deferred proceeds | 243.7 | 222.1 |
Liabilities and Equity: | ||
Long-term debt (incl. current maturities) | 2,916.2 | 2,665.7 |
Cumulative preferred stock of IPL | 200 | 203.8 |
WPL [Member] | ||
Liabilities and Equity: | ||
Long-term debt (incl. current maturities) | 2,020.9 | 2,147.9 |
Commodity Contracts [Member] | ||
Assets: | ||
Derivatives | 48 | 25.1 |
Liabilities and Equity: | ||
Derivatives | 22 | 41.7 |
Commodity Contracts [Member] | IPL [Member] | ||
Assets: | ||
Derivatives | 29.1 | 17.1 |
Liabilities and Equity: | ||
Derivatives | 9.7 | 19.4 |
Commodity Contracts [Member] | WPL [Member] | ||
Assets: | ||
Derivatives | 18.9 | 8 |
Liabilities and Equity: | ||
Derivatives | 12.3 | 22.3 |
Level 1 [Member] | ||
Assets: | ||
Money market fund investments | 228 | 0 |
Deferred proceeds | 0 | 0 |
Liabilities and Equity: | ||
Long-term debt (incl. current maturities) | 0 | 0 |
Cumulative preferred stock of IPL | 200 | 203.8 |
Level 1 [Member] | IPL [Member] | ||
Assets: | ||
Money market fund investments | 228 | 0 |
Deferred proceeds | 0 | 0 |
Liabilities and Equity: | ||
Long-term debt (incl. current maturities) | 0 | 0 |
Cumulative preferred stock of IPL | 200 | 203.8 |
Level 1 [Member] | WPL [Member] | ||
Liabilities and Equity: | ||
Long-term debt (incl. current maturities) | 0 | 0 |
Level 1 [Member] | Commodity Contracts [Member] | ||
Assets: | ||
Derivatives | 0 | 0 |
Liabilities and Equity: | ||
Derivatives | 0 | 0 |
Level 1 [Member] | Commodity Contracts [Member] | IPL [Member] | ||
Assets: | ||
Derivatives | 0 | 0 |
Liabilities and Equity: | ||
Derivatives | 0 | 0 |
Level 1 [Member] | Commodity Contracts [Member] | WPL [Member] | ||
Assets: | ||
Derivatives | 0 | 0 |
Liabilities and Equity: | ||
Derivatives | 0 | 0 |
Level 2 [Member] | ||
Assets: | ||
Money market fund investments | 0 | 0 |
Deferred proceeds | 0 | 0 |
Liabilities and Equity: | ||
Long-term debt (incl. current maturities) | 6,057.8 | 5,444.6 |
Cumulative preferred stock of IPL | 0 | 0 |
Level 2 [Member] | IPL [Member] | ||
Assets: | ||
Money market fund investments | 0 | 0 |
Deferred proceeds | 0 | 0 |
Liabilities and Equity: | ||
Long-term debt (incl. current maturities) | 2,916.2 | 2,665.7 |
Cumulative preferred stock of IPL | 0 | 0 |
Level 2 [Member] | WPL [Member] | ||
Liabilities and Equity: | ||
Long-term debt (incl. current maturities) | 2,020.9 | 2,147.9 |
Level 2 [Member] | Commodity Contracts [Member] | ||
Assets: | ||
Derivatives | 16.5 | 4.1 |
Liabilities and Equity: | ||
Derivatives | 14.7 | 8.5 |
Level 2 [Member] | Commodity Contracts [Member] | IPL [Member] | ||
Assets: | ||
Derivatives | 6.7 | 2 |
Liabilities and Equity: | ||
Derivatives | 5.5 | 2.9 |
Level 2 [Member] | Commodity Contracts [Member] | WPL [Member] | ||
Assets: | ||
Derivatives | 9.8 | 2.1 |
Liabilities and Equity: | ||
Derivatives | 9.2 | 5.6 |
Level 3 [Member] | ||
Assets: | ||
Money market fund investments | 0 | 0 |
Deferred proceeds | 243.7 | 222.1 |
Liabilities and Equity: | ||
Long-term debt (incl. current maturities) | 2.5 | 2.9 |
Cumulative preferred stock of IPL | 0 | 0 |
Level 3 [Member] | IPL [Member] | ||
Assets: | ||
Money market fund investments | 0 | 0 |
Deferred proceeds | 243.7 | 222.1 |
Liabilities and Equity: | ||
Long-term debt (incl. current maturities) | 0 | 0 |
Cumulative preferred stock of IPL | 0 | 0 |
Level 3 [Member] | WPL [Member] | ||
Liabilities and Equity: | ||
Long-term debt (incl. current maturities) | 0 | 0 |
Level 3 [Member] | Commodity Contracts [Member] | ||
Assets: | ||
Derivatives | 31.5 | 21 |
Liabilities and Equity: | ||
Derivatives | 7.3 | 33.2 |
Level 3 [Member] | Commodity Contracts [Member] | IPL [Member] | ||
Assets: | ||
Derivatives | 22.4 | 15.1 |
Liabilities and Equity: | ||
Derivatives | 4.2 | 16.5 |
Level 3 [Member] | Commodity Contracts [Member] | WPL [Member] | ||
Assets: | ||
Derivatives | 9.1 | 5.9 |
Liabilities and Equity: | ||
Derivatives | 3.1 | 16.7 |
Carrying Amount [Member] | ||
Assets: | ||
Money market fund investments | 228 | 0 |
Deferred proceeds | 243.7 | 222.1 |
Liabilities and Equity: | ||
Long-term debt (incl. current maturities) | 5,754.3 | 4,866.3 |
Cumulative preferred stock of IPL | 200 | 200 |
Carrying Amount [Member] | IPL [Member] | ||
Assets: | ||
Money market fund investments | 228 | 0 |
Deferred proceeds | 243.7 | 222.1 |
Liabilities and Equity: | ||
Long-term debt (incl. current maturities) | 2,801.8 | 2,406 |
Cumulative preferred stock of IPL | 200 | 200 |
Carrying Amount [Member] | WPL [Member] | ||
Liabilities and Equity: | ||
Long-term debt (incl. current maturities) | 1,834.5 | 1,833.4 |
Carrying Amount [Member] | Commodity Contracts [Member] | ||
Assets: | ||
Derivatives | 48 | 25.1 |
Liabilities and Equity: | ||
Derivatives | 22 | 41.7 |
Carrying Amount [Member] | Commodity Contracts [Member] | IPL [Member] | ||
Assets: | ||
Derivatives | 29.1 | 17.1 |
Liabilities and Equity: | ||
Derivatives | 9.7 | 19.4 |
Carrying Amount [Member] | Commodity Contracts [Member] | WPL [Member] | ||
Assets: | ||
Derivatives | 18.9 | 8 |
Liabilities and Equity: | ||
Derivatives | $ 12.3 | $ 22.3 |
Fair Value Measurements (Fair_2
Fair Value Measurements (Fair Value Measurements Using Significant Unobservable Inputs) (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | |||
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | ||
Commodity Contracts [Member] | |||||
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] | |||||
Beginning balance | $ (10.7) | $ 9.2 | $ (12.2) | $ 8.7 | |
Total net gains (losses) included in changes in net assets (realized/unrealized) | 25.7 | (4.3) | 15.7 | (31.3) | |
Transfers out of Level 3 | 15.6 | 0 | 15.6 | 12.2 | |
Purchases | 26.7 | 28.3 | |||
Sales | (0.2) | (0.1) | (0.2) | (0.3) | |
Settlements | (6.2) | (8.5) | (21.4) | (21.3) | |
Ending balance | 24.2 | (3.7) | 24.2 | (3.7) | |
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 | 26.1 | (4.2) | 16.5 | (29.4) | |
Commodity Contracts [Member] | IPL [Member] | |||||
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] | |||||
Beginning balance | (4.1) | 17.1 | (1.4) | 10.1 | |
Total net gains (losses) included in changes in net assets (realized/unrealized) | 16.8 | (4.4) | 7.6 | (13.9) | |
Transfers out of Level 3 | 10.5 | 0 | 10.5 | 3.1 | |
Purchases | 19.3 | 24.6 | |||
Sales | (0.1) | (0.1) | (0.1) | (0.2) | |
Settlements | (4.9) | (7.3) | (17.7) | (18.4) | |
Ending balance | 18.2 | 5.3 | 18.2 | 5.3 | |
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 | 16.8 | (4.5) | 7.9 | (12.6) | |
Commodity Contracts [Member] | WPL [Member] | |||||
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] | |||||
Beginning balance | (6.6) | (7.9) | (10.8) | (1.4) | |
Total net gains (losses) included in changes in net assets (realized/unrealized) | 8.9 | 0.1 | 8.1 | (17.4) | |
Transfers out of Level 3 | 5.1 | 0 | 5.1 | 9.1 | |
Purchases | 7.4 | 3.7 | |||
Sales | (0.1) | 0 | (0.1) | (0.1) | |
Settlements | (1.3) | (1.2) | (3.7) | (2.9) | |
Ending balance | 6 | (9) | 6 | (9) | |
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 | 9.3 | 0.3 | 8.6 | (16.8) | |
Deferred Proceeds [Member] | |||||
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] | |||||
Beginning balance | 208.3 | 170 | 222.1 | 211.1 | |
Total net gains (losses) included in changes in net assets (realized/unrealized) | 0 | 0 | 0 | 0 | |
Transfers out of Level 3 | 0 | 0 | 0 | 0 | |
Purchases | 0 | 0 | |||
Sales | 0 | 0 | 0 | 0 | |
Settlements | [1] | 35.4 | (54.7) | 21.6 | (95.8) |
Ending balance | 243.7 | 115.3 | 243.7 | 115.3 | |
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 | 0 | 0 | 0 | 0 | |
Deferred Proceeds [Member] | IPL [Member] | |||||
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] | |||||
Beginning balance | 208.3 | 170 | 222.1 | 211.1 | |
Total net gains (losses) included in changes in net assets (realized/unrealized) | 0 | 0 | 0 | 0 | |
Transfers out of Level 3 | 0 | 0 | 0 | 0 | |
Purchases | 0 | 0 | |||
Sales | 0 | 0 | 0 | 0 | |
Settlements | [1] | 35.4 | (54.7) | 21.6 | (95.8) |
Ending balance | 243.7 | 115.3 | 243.7 | 115.3 | |
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 | $ 0 | $ 0 | $ 0 | $ 0 | |
[1] | Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for doubtful accounts associated with the receivables sold and cash amounts received from the receivables sold. |
Fair Value Measurements (Fair_3
Fair Value Measurements (Fair Value Of Net Derivative Assets (Liabilities)) (Details) - Commodity Contracts [Member] - USD ($) $ in Millions | Sep. 30, 2018 | Jun. 30, 2018 | Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Dec. 31, 2016 |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||||||
Fair value, net derivative assets | $ 24.2 | $ (10.7) | $ (12.2) | $ (3.7) | $ 9.2 | $ 8.7 |
Excluding Financial Transmission Rights [Member] | ||||||
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||||||
Fair value, net derivative assets | 7.9 | |||||
Fair value, net derivative liabilities | 23.5 | |||||
Financial Transmission Rights [Member] | ||||||
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||||||
Fair value, net derivative assets | 16.3 | 11.3 | ||||
IPL [Member] | ||||||
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||||||
Fair value, net derivative assets | 18.2 | (4.1) | (1.4) | 5.3 | 17.1 | 10.1 |
IPL [Member] | Excluding Financial Transmission Rights [Member] | ||||||
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||||||
Fair value, net derivative assets | 5.4 | |||||
Fair value, net derivative liabilities | 11.5 | |||||
IPL [Member] | Financial Transmission Rights [Member] | ||||||
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||||||
Fair value, net derivative assets | 12.8 | 10.1 | ||||
WPL [Member] | ||||||
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||||||
Fair value, net derivative assets | 6 | $ (6.6) | (10.8) | $ (9) | $ (7.9) | $ (1.4) |
WPL [Member] | Excluding Financial Transmission Rights [Member] | ||||||
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||||||
Fair value, net derivative assets | 2.5 | |||||
Fair value, net derivative liabilities | 12 | |||||
WPL [Member] | Financial Transmission Rights [Member] | ||||||
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||||||
Fair value, net derivative assets | $ 3.5 | $ 1.2 |
Derivative Instruments (Notiona
Derivative Instruments (Notional Amounts Of Derivative Instruments) (Details) - Commodity [Member] gal in Thousands, T in Thousands, MWh in Thousands, Dekatherms in Thousands | 9 Months Ended |
Sep. 30, 2018DekathermsMWhTgal | |
Electricity (MWhs) [Member] | |
Notional Amount of Derivatives [Line Items] | |
Notional unit amount of derivatives (in MWhs) | 331 |
Electricity (MWhs) [Member] | IPL [Member] | |
Notional Amount of Derivatives [Line Items] | |
Notional unit amount of derivatives (in MWhs) | 0 |
Electricity (MWhs) [Member] | WPL [Member] | |
Notional Amount of Derivatives [Line Items] | |
Notional unit amount of derivatives (in MWhs) | 331 |
FTRs (MWhs) [Member] | |
Notional Amount of Derivatives [Line Items] | |
Notional unit amount of derivatives (in MWhs) | 16,553 |
FTRs (MWhs) [Member] | IPL [Member] | |
Notional Amount of Derivatives [Line Items] | |
Notional unit amount of derivatives (in MWhs) | 9,220 |
FTRs (MWhs) [Member] | WPL [Member] | |
Notional Amount of Derivatives [Line Items] | |
Notional unit amount of derivatives (in MWhs) | 7,333 |
Natural Gas (Dths) [Member] | |
Notional Amount of Derivatives [Line Items] | |
Notional unit amount of derivatives (in Dths) | Dekatherms | 179,275 |
Natural Gas (Dths) [Member] | IPL [Member] | |
Notional Amount of Derivatives [Line Items] | |
Notional unit amount of derivatives (in Dths) | Dekatherms | 83,485 |
Natural Gas (Dths) [Member] | WPL [Member] | |
Notional Amount of Derivatives [Line Items] | |
Notional unit amount of derivatives (in Dths) | Dekatherms | 95,790 |
Coal (Tons) [Member] | |
Notional Amount of Derivatives [Line Items] | |
Notional unit amount of derivatives (in Tons) | T | 11,922 |
Coal (Tons) [Member] | IPL [Member] | |
Notional Amount of Derivatives [Line Items] | |
Notional unit amount of derivatives (in Tons) | T | 4,849 |
Coal (Tons) [Member] | WPL [Member] | |
Notional Amount of Derivatives [Line Items] | |
Notional unit amount of derivatives (in Tons) | T | 7,073 |
Diesel Fuel (Gallons) [Member] | |
Notional Amount of Derivatives [Line Items] | |
Notional unit amount of derivatives (in Gallons) | gal | 3,906 |
Diesel Fuel (Gallons) [Member] | IPL [Member] | |
Notional Amount of Derivatives [Line Items] | |
Notional unit amount of derivatives (in Gallons) | gal | 0 |
Diesel Fuel (Gallons) [Member] | WPL [Member] | |
Notional Amount of Derivatives [Line Items] | |
Notional unit amount of derivatives (in Gallons) | gal | 3,906 |
Derivative Instruments (Fair Va
Derivative Instruments (Fair Value Of Financial Instruments) (Details) - Commodity Contracts [Member] - USD ($) $ in Millions | Sep. 30, 2018 | Dec. 31, 2017 |
Derivatives, Fair Value [Line Items] | ||
Current derivative assets | $ 39.7 | $ 21.1 |
Non-current derivative assets | 8.3 | 4 |
Current derivative liabilities | 7.2 | 18.7 |
Non-current derivative liabilities | 14.8 | 23 |
IPL [Member] | ||
Derivatives, Fair Value [Line Items] | ||
Current derivative assets | 26.2 | 15.8 |
Non-current derivative assets | 2.9 | 1.3 |
Current derivative liabilities | 3.2 | 5 |
Non-current derivative liabilities | 6.5 | 14.4 |
WPL [Member] | ||
Derivatives, Fair Value [Line Items] | ||
Current derivative assets | 13.5 | 5.3 |
Non-current derivative assets | 5.4 | 2.7 |
Current derivative liabilities | 4 | 13.7 |
Non-current derivative liabilities | $ 8.3 | $ 8.6 |
Commitments And Contingencies_2
Commitments And Contingencies (Narrative) (Details) $ in Millions | 9 Months Ended | |
Sep. 30, 2018USD ($) | ||
Commitments and Contingencies [Line Items] | ||
Minimum future commitments | $ 2,222 | |
Present value abandonment obligation | 36 | |
IPL [Member] | ||
Commitments and Contingencies [Line Items] | ||
Minimum future commitments | 1,565 | |
Indemnification obligations, maximum | 17 | |
WPL [Member] | ||
Commitments and Contingencies [Line Items] | ||
Minimum future commitments | 643 | |
Capital Purchase Obligation [Member] | ||
Commitments and Contingencies [Line Items] | ||
Minimum future commitments | 82 | |
Capital Purchase Obligation [Member] | IPL [Member] | ||
Commitments and Contingencies [Line Items] | ||
Minimum future commitments | 26 | |
Capital Purchase Obligation [Member] | WPL [Member] | ||
Commitments and Contingencies [Line Items] | ||
Minimum future commitments | 56 | |
Purchased Power [Member] | ||
Commitments and Contingencies [Line Items] | ||
Minimum future commitments | 1,089 | [1] |
Purchased Power [Member] | IPL [Member] | ||
Commitments and Contingencies [Line Items] | ||
Minimum future commitments | 1,063 | [1] |
Purchased Power [Member] | WPL [Member] | ||
Commitments and Contingencies [Line Items] | ||
Minimum future commitments | 26 | [1] |
Indemnification Agreement [Member] | ||
Commitments and Contingencies [Line Items] | ||
Indemnification obligations, maximum | 90 | |
Indemnification Agreement [Member] | Purchased Power [Member] | ||
Commitments and Contingencies [Line Items] | ||
Indemnification obligations, maximum | $ 17 | |
[1] | Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased. Alliant Energy’s and IPL’s amounts include minimum future commitments related to IPL’s purchase of capacity and the resulting energy from DAEC through December 2025. In July 2018, IPL entered into an amendment to shorten the term of the DAEC PPA by five years in exchange for a $110 million buyout payment by IPL in September 2020, which is not included in Alliant Energy’s and IPL’s amounts. The amendment to the DAEC PPA is contingent upon IUB approval of IPL’s July 2018 application regarding recovery of the buyout payment. |
Commitments And Contingencies_3
Commitments And Contingencies (Other Purchase Obligations) (Details) - USD ($) $ in Millions | 1 Months Ended | 9 Months Ended | ||
Sep. 30, 2020 | Jul. 31, 2018 | Sep. 30, 2018 | ||
Commitments and Contingencies [Line Items] | ||||
Minimum future commitments | $ 2,222 | |||
Individual commitments incurred | 1 | |||
IPL [Member] | ||||
Commitments and Contingencies [Line Items] | ||||
Minimum future commitments | 1,565 | |||
Individual commitments incurred | 1 | |||
WPL [Member] | ||||
Commitments and Contingencies [Line Items] | ||||
Minimum future commitments | 643 | |||
Individual commitments incurred | 1 | |||
Purchased Power [Member] | ||||
Commitments and Contingencies [Line Items] | ||||
Minimum future commitments | [1] | 1,089 | ||
Purchased Power [Member] | IPL [Member] | ||||
Commitments and Contingencies [Line Items] | ||||
Minimum future commitments | [1] | 1,063 | ||
Purchased Power [Member] | WPL [Member] | ||||
Commitments and Contingencies [Line Items] | ||||
Minimum future commitments | [1] | 26 | ||
Natural gas [Member] | ||||
Commitments and Contingencies [Line Items] | ||||
Minimum future commitments | 921 | |||
Natural gas [Member] | IPL [Member] | ||||
Commitments and Contingencies [Line Items] | ||||
Minimum future commitments | 394 | |||
Natural gas [Member] | WPL [Member] | ||||
Commitments and Contingencies [Line Items] | ||||
Minimum future commitments | 527 | |||
Coal [Member] | ||||
Commitments and Contingencies [Line Items] | ||||
Minimum future commitments | [2] | 169 | ||
Coal [Member] | IPL [Member] | ||||
Commitments and Contingencies [Line Items] | ||||
Minimum future commitments | [2] | 84 | ||
Coal [Member] | WPL [Member] | ||||
Commitments and Contingencies [Line Items] | ||||
Minimum future commitments | [2] | 85 | ||
Other [Member] | ||||
Commitments and Contingencies [Line Items] | ||||
Minimum future commitments | [3] | 43 | ||
Other [Member] | IPL [Member] | ||||
Commitments and Contingencies [Line Items] | ||||
Minimum future commitments | [3] | 24 | ||
Other [Member] | WPL [Member] | ||||
Commitments and Contingencies [Line Items] | ||||
Minimum future commitments | [3] | $ 5 | ||
DAEC PPA [Member] | ||||
Commitments and Contingencies [Line Items] | ||||
PPA term amendment | 5 years | |||
Scenario, Forecast [Member] | DAEC PPA [Member] | ||||
Commitments and Contingencies [Line Items] | ||||
PPA buyout payment | $ 110 | |||
[1] | Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased. Alliant Energy’s and IPL’s amounts include minimum future commitments related to IPL’s purchase of capacity and the resulting energy from DAEC through December 2025. In July 2018, IPL entered into an amendment to shorten the term of the DAEC PPA by five years in exchange for a $110 million buyout payment by IPL in September 2020, which is not included in Alliant Energy’s and IPL’s amounts. The amendment to the DAEC PPA is contingent upon IUB approval of IPL’s July 2018 application regarding recovery of the buyout payment. | |||
[2] | Corporate Services entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. These commitments were assigned to IPL and WPL based on information available as of September 30, 2018 regarding expected future usage, which is subject to change. | |||
[3] | Includes individual commitments incurred during the normal course of business that exceeded $1 million at September 30, 2018. |
Commitments And Contingencies_4
Commitments And Contingencies (MPG Site Estimated Future Costs And Recorded Liabilities) (Details) - Manufactured Gas Plant Sites [Member] $ in Millions | 9 Months Ended |
Sep. 30, 2018USD ($) | |
Commitments and Contingencies [Line Items] | |
Minimum range of estimated future costs | $ 11 |
Maximum range of estimated future costs | 29 |
Current and non-current environmental liabilities | 16 |
IPL [Member] | |
Commitments and Contingencies [Line Items] | |
Minimum range of estimated future costs | 9 |
Maximum range of estimated future costs | 25 |
Current and non-current environmental liabilities | $ 13 |
Segments Of Business (Schedule
Segments Of Business (Schedule Of Segments Of Business) (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | ||
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | |
Segment Reporting Information [Line Items] | ||||
Revenues | $ 928.6 | $ 906.9 | $ 2,661 | $ 2,526.1 |
Operating income (loss) | 256.1 | 236.3 | 573 | 537.2 |
Income from continuing operations, net of tax | 205.5 | 168.8 | 426.8 | 362.1 |
Income from discontinued operations, net of tax | 0 | 0 | 0 | 1.4 |
Net income attributable to common shareowners | 205.5 | 168.8 | 426.8 | 363.5 |
IPL [Member] | ||||
Segment Reporting Information [Line Items] | ||||
Revenues | 547.6 | 527.4 | 1,548.2 | 1,398.1 |
Operating income (loss) | 143.1 | 133.8 | 296.4 | 253.2 |
Net income attributable to common shareowners | 126.5 | 120.4 | 224.9 | 200.4 |
WPL [Member] | ||||
Segment Reporting Information [Line Items] | ||||
Revenues | 370.7 | 370.2 | 1,083.2 | 1,098.1 |
Operating income (loss) | 104.2 | 93.5 | 251.6 | 258.3 |
Net income attributable to common shareowners | 76.3 | 49.8 | 170.1 | 133.4 |
Electric [Member] | ||||
Segment Reporting Information [Line Items] | ||||
Revenues | 861.2 | 840.6 | 2,296.2 | 2,199.1 |
Operating income (loss) | 248.7 | 236.7 | 510.2 | 486.9 |
Electric [Member] | IPL [Member] | ||||
Segment Reporting Information [Line Items] | ||||
Revenues | 509.2 | 489 | 1,337 | 1,217.6 |
Operating income (loss) | 144.7 | 140 | 275.7 | 239.2 |
Electric [Member] | WPL [Member] | ||||
Segment Reporting Information [Line Items] | ||||
Revenues | 352 | 351.6 | 959.2 | 981.5 |
Operating income (loss) | 104 | 96.7 | 234.5 | 247.7 |
Gas [Member] | ||||
Segment Reporting Information [Line Items] | ||||
Revenues | 44.8 | 45.8 | 299 | 262.7 |
Operating income (loss) | (2) | (1.7) | 34.9 | 31.3 |
Gas [Member] | IPL [Member] | ||||
Segment Reporting Information [Line Items] | ||||
Revenues | 26.7 | 27.4 | 177 | 147.2 |
Operating income (loss) | (3.1) | (1.8) | 16.3 | 15.4 |
Gas [Member] | WPL [Member] | ||||
Segment Reporting Information [Line Items] | ||||
Revenues | 18.1 | 18.4 | 122 | 115.5 |
Operating income (loss) | 1.1 | 0.1 | 18.6 | 15.9 |
Other Utility [Member] | ||||
Segment Reporting Information [Line Items] | ||||
Revenues | 12.3 | 11.2 | 36.2 | 34.4 |
Operating income (loss) | 0.6 | (7.7) | 2.9 | (6.7) |
Other Utility [Member] | IPL [Member] | ||||
Segment Reporting Information [Line Items] | ||||
Revenues | 11.7 | 11 | 34.2 | 33.3 |
Operating income (loss) | 1.5 | (4.4) | 4.4 | (1.4) |
Other Utility [Member] | WPL [Member] | ||||
Segment Reporting Information [Line Items] | ||||
Revenues | 0.6 | 0.2 | 2 | 1.1 |
Operating income (loss) | (0.9) | (3.3) | (1.5) | (5.3) |
Utility Business [Member] | ||||
Segment Reporting Information [Line Items] | ||||
Revenues | 918.3 | 897.6 | 2,631.4 | 2,496.2 |
Operating income (loss) | 247.3 | 227.3 | 548 | 511.5 |
Income from continuing operations, net of tax | 333.8 | |||
Income from discontinued operations, net of tax | 0 | |||
Net income attributable to common shareowners | 202.8 | 170.2 | 395 | 333.8 |
Non-Utility [Member] | ATC Holdings, Non-Utility, Parent and Other [Member] | ||||
Segment Reporting Information [Line Items] | ||||
Revenues | 10.3 | 9.3 | 29.6 | 29.9 |
Operating income (loss) | 8.8 | 9 | 25 | 25.7 |
Income from continuing operations, net of tax | 28.3 | |||
Income from discontinued operations, net of tax | 1.4 | |||
Net income attributable to common shareowners | $ 2.7 | $ (1.4) | $ 31.8 | $ 29.7 |
Related Parties (Narrative) (De
Related Parties (Narrative) (Details) - USD ($) $ in Millions | Sep. 30, 2018 | Dec. 31, 2017 |
ATC [Member] | WPL Owed ATC LLC [Member] | Equity Method Investee [Member] | ||
Related Party Transactions [Line Items] | ||
Net amounts owed | $ 8 | $ 9 |
Related Parties (Service Agreem
Related Parties (Service Agreements) (Details) - Corporate Services [Member] - Subsidiary of Common Parent [Member] - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | ||
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | |
Administrative and General Services Billings [Member] | IPL [Member] | ||||
Related Party Transactions [Line Items] | ||||
Amounts billed between related parties | $ 43 | $ 48 | $ 128 | $ 130 |
Administrative and General Services Billings [Member] | WPL [Member] | ||||
Related Party Transactions [Line Items] | ||||
Amounts billed between related parties | 33 | 37 | 100 | 100 |
Sales Credited [Member] | IPL [Member] | ||||
Related Party Transactions [Line Items] | ||||
Amounts billed between related parties | 11 | 8 | 34 | 15 |
Sales Credited [Member] | WPL [Member] | ||||
Related Party Transactions [Line Items] | ||||
Amounts billed between related parties | 7 | 6 | 16 | 8 |
Purchases Billed [Member] | IPL [Member] | ||||
Related Party Transactions [Line Items] | ||||
Amounts billed between related parties | 95 | 109 | 268 | 271 |
Purchases Billed [Member] | WPL [Member] | ||||
Related Party Transactions [Line Items] | ||||
Amounts billed between related parties | $ 19 | $ 32 | $ 56 | $ 99 |
Related Parties (Net Intercompa
Related Parties (Net Intercompany Payables) (Details) - Subsidiary of Common Parent [Member] - Corporate Services [Member] - USD ($) $ in Millions | Sep. 30, 2018 | Dec. 31, 2017 |
IPL [Member] | ||
Related Party Transactions [Line Items] | ||
Net amounts owed | $ 109 | $ 114 |
WPL [Member] | ||
Related Party Transactions [Line Items] | ||
Net amounts owed | $ 65 | $ 61 |
Related Parties (Amounts Billed
Related Parties (Amounts Billed Between Parties) (Details) - ATC [Member] - Equity Method Investee [Member] - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | ||
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | |
ATC Billings To WPL [Member] | ||||
Related Party Transactions [Line Items] | ||||
Amounts billed between related parties | $ 26 | $ 26 | $ 79 | $ 79 |
WPL Billings To ATC [Member] | ||||
Related Party Transactions [Line Items] | ||||
Amounts billed between related parties | $ 3 | $ 2 | $ 8 | $ 8 |