Commitments And Contingencies (Other Purchase Commitments) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2021 USD ($)
Commitments and Contingencies [Line Items]
Minimum future commitments	$ 1,201
Individual commitments incurred	1
IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	639
Individual commitments incurred	1
WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	538
Individual commitments incurred	1
Natural gas [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	985
Natural gas [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	514
Natural gas [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	471
Coal [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	82
Coal [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	54
Coal [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	28
Other [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	134
Other [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	71
Other [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	$ 39