Commitments And Contingencies (Other Purchase Commitments) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2021 USD ($)
Commitments and Contingencies [Line Items]
Minimum future commitments	$ 1,122
Individual commitments incurred	1
IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	569
Individual commitments incurred	1
WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	523
Individual commitments incurred	1
Natural gas [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	909
Natural gas [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	456
Natural gas [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	453
Coal [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	89
Coal [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	48
Coal [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	41
Other [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	124
Other [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	65
Other [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	$ 29