Commitments And Contingencies (Other Purchase Commitments) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2021 USD ($)
Commitments and Contingencies [Line Items]
Minimum future commitments	$ 1,174
Individual commitments incurred	1
IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	581
Individual commitments incurred	1
WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	561
Individual commitments incurred	1
Natural gas [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	958
Natural gas [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	466
Natural gas [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	492
Coal [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	94
Coal [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	55
Coal [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	39
Other [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	122
Other [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	60
Other [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	$ 30