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v3.20.2

Common Equity (Changes in Shareowners' Equity) (Details) - USD ($) $ / shares in Units, $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2020 | Mar. 31, 2020 | Jun. 30, 2019 | Jun. 30, 2020 | Jun. 30, 2019
Changes in Shareowners' Equity Roll Forward [Line Items] |  |  |  |  |
Beginning balance |  | $ 5,205.1 |  | $ 5,205.1 |
Beginning balance | $ 5,702.4 | 5,405.1 | $ 4,882.4 | 5,405.1 | $ 4,785.7
Net income attributable to common shareowners | 134.4 |  | 94.6 | 304.4 | 219.7
Net income | 136.9 |  | 97.1 | 309.5 | 224.8
Common stock dividends | (94.6) |  | (84.1) | (187.6) | (167.8)
Equity forward settlements and Shareowner Direct Plan issuances | 6.4 |  | 6.0 | 234.8 | 60.6
Equity-based compensation plans and other | 2.3 |  | 2.1 | 2.2 | 2.1
Adoption of new accounting standard, net of tax |  |  |  | (8.7) |
Other comprehensive loss, net of tax | (2.6) |  | (1.4) | (1.9) | (0.7)
Ending balance | 5,548.3 |  |  | 5,548.3 |
Ending balance | $ 5,748.3 | 5,702.4 | $ 4,899.6 | $ 5,748.3 | $ 4,899.6
Common stock dividends (in dollars per share) | $ 0.38 |  | $ 0.355 | $ 0.76 | $ 0.71
Common Stock [Member] |  |  |  |  |
Changes in Shareowners' Equity Roll Forward [Line Items] |  |  |  |  |
Beginning balance | $ 2.5 | 2.5 | $ 2.4 | $ 2.5 | $ 2.4
Equity forward settlements and Shareowner Direct Plan issuances |  |  |  |  |
Ending balance | 2.5 | 2.5 | 2.4 | 2.5 | 2.4
Additional Paid-in Capital [Member] |  |  |  |  |
Changes in Shareowners' Equity Roll Forward [Line Items] |  |  |  |  |
Beginning balance | 2,674.1 | 2,445.9 | 2,100.0 | 2,445.9 | 2,045.5
Equity forward settlements and Shareowner Direct Plan issuances | 6.4 |  | 6.0 | 234.8 | 60.6
Equity-based compensation plans and other | 2.6 |  | 2.4 | 2.4 | 2.3
Ending balance | 2,683.1 | 2,674.1 | 2,108.4 | 2,683.1 | 2,108.4
Retained Earnings [Member] |  |  |  |  |
Changes in Shareowners' Equity Roll Forward [Line Items] |  |  |  |  |
Beginning balance | 2,833.7 | 2,765.4 | 2,587.3 | 2,765.4 | 2,545.9
Net income attributable to common shareowners | 134.4 |  | 94.6 | 304.4 | 219.7
Common stock dividends | (94.6) |  | (84.1) | (187.6) | (167.8)
Ending balance | 2,873.5 | 2,833.7 | 2,597.8 | 2,873.5 | 2,597.8
Accumulated Other Comprehensive Income (Loss) [Member] |  |  |  |  |
Changes in Shareowners' Equity Roll Forward [Line Items] |  |  |  |  |
Beginning balance | 2.0 | 1.3 | 2.4 | 1.3 | 1.7
Other comprehensive loss, net of tax | (2.6) |  | (1.4) | (1.9) | (0.7)
Ending balance | (0.6) | 2.0 | 1.0 | (0.6) | 1.0
Shares in Deferred Compensation Trust [Member] |  |  |  |  |
Changes in Shareowners' Equity Roll Forward [Line Items] |  |  |  |  |
Beginning balance | (9.9) | (10.0) | (9.7) | (10.0) | (9.8)
Equity-based compensation plans and other | (0.3) |  | (0.3) | (0.2) | (0.2)
Ending balance | (10.2) | (9.9) | (10.0) | (10.2) | (10.0)
Cumulative Preferred Stock [Member] |  |  |  |  |
Changes in Shareowners' Equity Roll Forward [Line Items] |  |  |  |  |
Beginning balance | 200.0 | 200.0 | 200.0 | 200.0 | 200.0
Ending balance | 200.0 | 200.0 | 200.0 | 200.0 | 200.0
IPL [Member] |  |  |  |  |
Changes in Shareowners' Equity Roll Forward [Line Items] |  |  |  |  |
Beginning balance |  | 3,271.8 |  | 3,271.8 |
Beginning balance | 3,595.4 | 3,471.8 | 3,342.0 | 3,471.8 | 3,230.7
Net income attributable to common shareowners | 59.8 |  | 45.0 | 142.4 | 98.3
Net income | 62.3 |  | 47.5 | 147.5 | 103.4
Common stock dividends | (59.1) |  | (41.9) | (118.1) | (83.9)
Capital contributions from parent | 75.0 |  |  | 175.0 | 100.0
Ending balance | 3,471.1 |  |  | 3,471.1 |
Ending balance | 3,671.1 | 3,595.4 | 3,345.1 | 3,671.1 | 3,345.1
IPL [Member] | Common Stock [Member] |  |  |  |  |
Changes in Shareowners' Equity Roll Forward [Line Items] |  |  |  |  |
Beginning balance | 33.4 | 33.4 | 33.4 | 33.4 | 33.4
Ending balance | 33.4 | 33.4 | 33.4 | 33.4 | 33.4
IPL [Member] | Additional Paid-in Capital [Member] |  |  |  |  |
Changes in Shareowners' Equity Roll Forward [Line Items] |  |  |  |  |
Beginning balance | 2,447.8 | 2,347.8 | 2,322.8 | 2,347.8 | 2,222.8
Capital contributions from parent | 75.0 |  |  | 175.0 | 100.0
Ending balance | 2,522.8 | 2,447.8 | 2,322.8 | 2,522.8 | 2,322.8
IPL [Member] | Retained Earnings [Member] |  |  |  |  |
Changes in Shareowners' Equity Roll Forward [Line Items] |  |  |  |  |
Beginning balance | 914.2 | 890.6 | 785.8 | 890.6 | 774.5
Net income attributable to common shareowners | 59.8 |  | 45.0 | 142.4 | 98.3
Common stock dividends | (59.1) |  | (41.9) | (118.1) | (83.9)
Ending balance | 914.9 | 914.2 | 788.9 | 914.9 | 788.9
IPL [Member] | Cumulative Preferred Stock [Member] |  |  |  |  |
Changes in Shareowners' Equity Roll Forward [Line Items] |  |  |  |  |
Beginning balance | 200.0 | 200.0 | 200.0 | 200.0 | 200.0
Ending balance | 200.0 | 200.0 | 200.0 | 200.0 | 200.0
WPL [Member] |  |  |  |  |
Changes in Shareowners' Equity Roll Forward [Line Items] |  |  |  |  |
Beginning balance |  | 2,363.6 |  | 2,363.6 |
Beginning balance | 2,436.1 | 2,363.6 | 2,179.2 | 2,363.6 | 2,149.5
Net income | 57.6 |  | 42.0 | 147.2 | 107.7
Common stock dividends | (41.9) |  | (36.0) | (84.0) | (72.0)
Capital contributions from parent |  |  |  | 25.0 | 0.0
Ending balance | 2,451.8 |  |  | 2,451.8 |
Ending balance | 2,451.8 | 2,436.1 | 2,185.2 | 2,451.8 | 2,185.2
WPL [Member] | Common Stock [Member] |  |  |  |  |
Changes in Shareowners' Equity Roll Forward [Line Items] |  |  |  |  |
Beginning balance | 66.2 | 66.2 | 66.2 | 66.2 | 66.2
Ending balance | 66.2 | 66.2 | 66.2 | 66.2 | 66.2
WPL [Member] | Additional Paid-in Capital [Member] |  |  |  |  |
Changes in Shareowners' Equity Roll Forward [Line Items] |  |  |  |  |
Beginning balance | 1,459.0 | 1,434.0 | 1,309.0 | 1,434.0 | 1,309.0
Capital contributions from parent |  |  |  | 25.0 |
Ending balance | 1,459.0 | 1,459.0 | 1,309.0 | 1,459.0 | 1,309.0
WPL [Member] | Retained Earnings [Member] |  |  |  |  |
Changes in Shareowners' Equity Roll Forward [Line Items] |  |  |  |  |
Beginning balance | 910.9 | 863.4 | 804.0 | 863.4 | 774.3
Net income | 57.6 |  | 42.0 | 147.2 | 107.7
Common stock dividends | (41.9) |  | (36.0) | (84.0) | (72.0)
Ending balance | $ 926.6 | $ 910.9 | $ 810.0 | 926.6 | $ 810.0
Credit Losses ASU [Member] | Retained Earnings [Member] |  |  |  |  |
Changes in Shareowners' Equity Roll Forward [Line Items] |  |  |  |  |
Adoption of new accounting standard, net of tax |  |  |  | $ (8.7) |

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