| Fiscal period | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 | 2014 | 2013 | 2012 | 2011 |
|---|
| Period End Date | 12/31/2020 | 12/31/2019 | 12/31/2018 | 12/31/2017 | 12/31/2016 | 12/31/2015 | 12/31/2014 | 12/31/2013 | 12/31/2012 | 12/31/2011 |
|---|
| Utility: Gas | 373.00 | 455.00 | 447.00 | 400.90 | 355.40 | 381.20 | 517.50 | 464.80 | 396.30 | 476.70 |
| Utility: Electric | 2,920.00 | 3,064.00 | 3,000.00 | 2,894.70 | 2,875.50 | 2,770.50 | 2,713.60 | 2,689.00 | 2,589.30 | 2,635.80 |
| Utility: Other | 49.00 | 46.00 | 48.00 | 47.50 | 48.60 | 57.90 | 66.10 | 71.30 | 56.70 | 62.00 |
| Utility: Non-regulated | 74.00 | 83.00 | 39.00 | 39.10 | 40.50 | 44.00 | 53.10 | 51.70 | 52.20 | 46.90 |
| Total revenues | 3,416.00 | 3,648.00 | 3,534.00 | 3,382.20 | 3,320.00 | 3,253.60 | 3,350.30 | 3,276.80 | 3,094.50 | 3,221.40 |
| Cost of gas sold | 182.00 | 222.00 | 232.00 | 211.40 | 194.30 | 219.10 | 327.80 | 276.70 | 217.20 | 295.20 |
| Purchased power | -- | -- | -- | -- | -- | -- | -- | -- | 271.50 | 257.20 |
| Electric production fuel and purchased power | 652.00 | 777.00 | 855.00 | 818.10 | 854.00 | 837.70 | 877.20 | 941.80 | 712.30 | 764.50 |
| Other operation and maintenance | 670.00 | 712.00 | 646.00 | -- | 589.40 | 629.50 | 665.00 | 635.60 | 590.00 | 630.20 |
| Other | -- | -- | -- | 633.20 | -- | -- | -- | -- | -- | -- |
| Non-regulated operation and maintenance | -- | -- | -- | -- | -- | -- | -- | -- | 11.90 | 18.00 |
| Electric transmission service | 449.00 | 481.00 | 496.00 | 480.90 | 527.90 | 485.30 | 447.50 | 418.30 | 341.30 | 323.80 |
| Depreciation and amortization | 615.00 | 567.00 | 507.00 | 461.80 | 411.60 | 401.30 | 388.10 | 370.90 | 332.40 | 321.00 |
| Taxes other than income taxes | 108.00 | 111.00 | 104.00 | 105.60 | 102.30 | 103.70 | 101.10 | 99.60 | 98.20 | 98.20 |
| Asset valuation charges for Franklin County wind farm | -- | -- | -- | -- | (86.40) | 0.00 | 0.00 | -- | -- | -- |
| Total Operating Expenses | 2,676.00 | 2,870.00 | 2,840.00 | 2,711.00 | 2,765.90 | 2,676.60 | 2,806.70 | 2,742.90 | 2,574.80 | 2,708.10 |
| Operating income (loss) | 740.00 | 778.00 | 694.00 | 671.20 | 554.10 | 577.00 | 543.60 | 533.90 | 519.70 | 513.30 |
| Interest expense | 275.00 | 273.00 | 247.00 | 215.60 | 196.20 | 187.10 | 180.60 | 172.80 | 156.70 | 158.30 |
| Impairment of available-for-sale securities of McLeodUSA Inc | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Gain on reclassification of investment | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Gain on sale of IPL"s electric transmission assets | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Gain on sale of Alliant Energy New Zealand Ltd. stock | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Preferred dividend requirements of subsidiaries | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Equity income from unconsolidated investments | 61.00 | 53.00 | 55.00 | 44.80 | 39.60 | 33.80 | 40.40 | 43.70 | 41.30 | 39.30 |
| Gains on sales of McLeodUSA Inc. stock | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Interest income and other | -- | -- | -- | -- | -- | 0.70 | 1.80 | 0.40 | 4.00 | 4.30 |
| Interest income from loans to discontinued operations, net | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Allowance for funds used during construction | 55.00 | 93.00 | 76.00 | 49.70 | 62.50 | 36.90 | 34.80 | 30.80 | 21.90 | 12.00 |
| Other | (14.00) | (15.00) | (8.00) | (17.30) | (16.60) | -- | -- | -- | -- | -- |
| Miscellaneous, net | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Loss on early extinguishment of debt | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Asset valuation charges - Brazil investments | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Pre-Tax Income | 567.00 | 636.00 | 570.00 | 532.80 | 443.40 | 461.30 | 440.00 | 436.00 | 430.20 | 410.60 |
| Income tax expense (benefit) | (57.00) | 69.00 | 48.00 | 66.70 | 59.40 | 70.40 | 44.30 | 53.90 | 89.40 | 69.20 |
| Current tax expense (benefit) : Federal | -- | -- | -- | -- | -- | -- | 36.60 | 4.40 | (29.30) | -- |
| Current tax expense (benefit) : State | -- | -- | -- | -- | -- | -- | 9.30 | (3.60) | 11.60 | -- |
| Deferred tax expense (benefit): Federal | -- | -- | -- | -- | -- | -- | 83.50 | 123.90 | 157.80 | -- |
| Deferred tax expense (benefit): State | -- | -- | -- | -- | -- | -- | 4.60 | 15.60 | 23.90 | -- |
| Foreign tax expense | -- | -- | -- | -- | -- | -- | -- | -- | (0.20) | -- |
| Research and development tax credits | -- | -- | -- | -- | -- | -- | (56.70) | -- | -- | -- |
| Other tax credits | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Other Amortization of investment tax credits | -- | -- | -- | -- | -- | -- | (1.60) | (1.60) | -- | -- |
| Oil, gas and alternative fuel credits | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Affordable housing tax credits | -- | -- | -- | -- | -- | -- | -- | -- | (48.30) | -- |
| Current tax expense (benefit): Nonconventional fuel credits | -- | -- | -- | -- | -- | -- | -- | -- | 8.00 | -- |
| Deferred tax expense (benefit Nonconventional fuel credits | -- | -- | -- | -- | -- | -- | -- | -- | (7.60) | -- |
| Provision recorded as a change in uncertain tax benefits | -- | -- | -- | -- | -- | -- | (31.30) | -- | (24.80) | -- |
| Provision recorded as a change in accrued interest | -- | -- | -- | -- | -- | -- | (0.10) | -- | (1.70) | -- |
| Income from continuing operations | -- | -- | -- | 466.10 | 384.00 | 390.90 | 395.70 | 382.10 | 340.80 | 341.40 |
| Income (Loss) from Discontinued Operations, Net of Tax | -- | -- | -- | 1.40 | (2.30) | (2.50) | (2.40) | (5.90) | (5.10) | (19.50) |
| Income (loss) before cumulative effect of changes in accounting principles | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Cumulative effect of changes in accounting principles | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Consolidated Net Income (Loss) | 624.00 | 567.00 | 522.00 | 467.50 | 381.70 | 388.40 | 393.30 | 376.20 | 335.70 | 321.90 |
| Preferred dividend requirements of subsidiaries | 10.00 | 10.00 | 10.00 | 10.20 | 10.20 | 10.20 | 10.20 | 17.90 | 15.90 | 18.30 |
| Net Income (Loss) Available to Common Shareholders | 614.00 | 557.00 | 512.00 | 457.30 | 371.50 | 378.20 | 383.10 | 358.30 | 319.80 | 303.60 |
| Earnings Per Share (Basic) - Cont Ops | -- | -- | -- | -- | 1.65 | 1.69 | 1.74 | 1.65 | 1.47 | 1.46 |
| Earnings Per Share (Basic) - Disc Ops | -- | -- | -- | -- | (0.01) | (0.01) | (0.01) | (0.03) | (0.02) | (0.09) |
| Earnings Per Share (Basic) - Acc Change | -- | -- | -- | -- | 1.64 | -- | -- | -- | -- | -- |
| NET EARNINGS PER SHARE (BASIC) | 2.47 | 2.34 | 2.19 | 1.99 | 1.64 | 1.68 | 1.73 | 1.62 | 1.45 | 1.37 |
| Earnings Per Share (Diluted) - Cont Ops | -- | -- | -- | -- | 1.65 | 1.69 | 1.74 | 1.65 | 1.47 | 1.46 |
| Earnings Per Share (Diluted) - Disc Ops | -- | -- | -- | -- | (0.01) | (0.01) | (0.01) | (0.03) | (0.02) | (0.09) |
| Earnings Per Share (Diluted) - Acc Change | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| NET EARNINGS PER SHARE (DILUTED) | 2.47 | 2.33 | 2.19 | 1.99 | 1.64 | 1.68 | 1.73 | 1.62 | 1.45 | 1.37 |
| Weighted Average Shares Outstanding (Basic) | 248.40 | 238.50 | 233.60 | 229.70 | 227.10 | 225.40 | 221.70 | 221.60 | 221.60 | 221.40 |
| Weighted Average Shares Outstanding (Diluted) | 248.70 | 239.00 | 233.60 | 229.70 | 227.10 | 225.40 | 221.70 | 221.60 | 221.60 | 221.40 |