Commitments And Contingencies (Other Purchase Commitments) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2020 USD ($)
Commitments and Contingencies [Line Items]
Minimum future commitments	$ 1,219
Individual commitments incurred	1
IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	627
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	983
Natural gas [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	508
Natural gas [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	475
Coal [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	125
Coal [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	70
Coal [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	55
Other [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	111
Other [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	49
Other [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	$ 31