Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

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Amount of expected credit loss for credit exposure on off-balance-sheet commitment, including but not limited to, loan commitment, standby letter of credit, financial guarantee not accounted for as insurance. Excludes off-balance sheet credit exposure accounted for as insurance and instrument accounted for under derivatives and hedging.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Commitments And Contingencies (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2021	Dec. 31, 2020
Commitments and Contingencies [Line Items]
Minimum future commitments	$ 1,275
IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	596
WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	631
Capital Purchase Commitment [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	221
Capital Purchase Commitment [Member] \| IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	175
Capital Purchase Commitment [Member] \| WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	46
Indemnification Agreement [Member]
Commitments and Contingencies [Line Items]
Obligations, maximum	51
Indemnification Agreement [Member] \| Purchased Power [Member]
Commitments and Contingencies [Line Items]
Obligations, maximum	$ 17
Whiting Petroleum Affiliate [Member]
Commitments and Contingencies [Line Items]
Partnership share, percent	6.00%
Obligations, maximum	$ 58
Credit loss liability	$ 5
Federal Energy Regulatory Commission [Member]
Commitments and Contingencies [Line Items]
MISO base return on equity, percentage		10.02%	9.88%