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Commitments And Contingencies (Narrative) (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Long-term Purchase Commitment [Line Items] |  |  |  |  |
Equity income from unconsolidated investments, net | $ 61 | $ 51 | $ 62 |  |
Workforce Subject to Collective Bargaining Arrangements [Member] |  |  |  |  |
Long-term Purchase Commitment [Line Items] |  |  |  |  |
Employees covered by collective bargaining agreement | 53.00% |  |  |  |
Workforce Subject to Collective Bargaining Arrangements Expiring within One Year [Member] |  |  |  |  |
Long-term Purchase Commitment [Line Items] |  |  |  |  |
Employees covered by collective bargaining agreement | 18.00% |  |  |  |
Whiting Petroleum Affiliate [Member] |  |  |  |  |
Long-term Purchase Commitment [Line Items] |  |  |  |  |
Partnership share, percent | 6.00% |  |  |  |
Obligations, maximum | $ 49 |  |  |  |
Capital Purchase Commitment [Member] |  |  |  |  |
Long-term Purchase Commitment [Line Items] |  |  |  |  |
Minimum future commitments | $ 188 |  |  |  |
IPL [Member] | Workforce Subject to Collective Bargaining Arrangements [Member] |  |  |  |  |
Long-term Purchase Commitment [Line Items] |  |  |  |  |
Employees covered by collective bargaining agreement | 69.00% |  |  |  |
IPL [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring within One Year [Member] |  |  |  |  |
Long-term Purchase Commitment [Line Items] |  |  |  |  |
Employees covered by collective bargaining agreement | 53.00% |  |  |  |
IPL [Member] | Capital Purchase Commitment [Member] |  |  |  |  |
Long-term Purchase Commitment [Line Items] |  |  |  |  |
Minimum future commitments | $ 131 |  |  |  |
WPL [Member] | Workforce Subject to Collective Bargaining Arrangements [Member] |  |  |  |  |
Long-term Purchase Commitment [Line Items] |  |  |  |  |
Employees covered by collective bargaining agreement | 83.00% |  |  |  |
WPL [Member] | Capital Purchase Commitment [Member] |  |  |  |  |
Long-term Purchase Commitment [Line Items] |  |  |  |  |
Minimum future commitments | $ 57 |  |  |  |
Indemnification Agreement [Member] |  |  |  |  |
Long-term Purchase Commitment [Line Items] |  |  |  |  |
Obligations, maximum | 51 |  |  |  |
Indemnification Agreement [Member] | Purchased Power [Member] |  |  |  |  |
Long-term Purchase Commitment [Line Items] |  |  |  |  |
Obligations, maximum | 17 |  |  |  |
Indemnification Agreement [Member] | Renewable Tax Credits Transferred [Member] |  |  |  |  |
Long-term Purchase Commitment [Line Items] |  |  |  |  |
Guarantor Obligations, Liquidation Proceeds, Monetary Amount | 98 |  |  |  |
Indemnification Agreement [Member] | IPL [Member] | Renewable Tax Credits Transferred [Member] |  |  |  |  |
Long-term Purchase Commitment [Line Items] |  |  |  |  |
Guarantor Obligations, Liquidation Proceeds, Monetary Amount | 76 |  |  |  |
Indemnification Agreement [Member] | WPL [Member] | Renewable Tax Credits Transferred [Member] |  |  |  |  |
Long-term Purchase Commitment [Line Items] |  |  |  |  |
Guarantor Obligations, Liquidation Proceeds, Monetary Amount | $ 22 |  |  |  |
FERC [Member] |  |  |  |  |
Long-term Purchase Commitment [Line Items] |  |  |  |  |
Base return on equity, percentage |  |  |  | 10.02% | 9.88%
Equity income from unconsolidated investments, net |  | $ 6 |  |  |

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