Commitments And Contingencies (Operating Expense Purchase Obligations) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($)
Commitments and Contingencies [Line Items]
Minimum future commitments	$ 2,213
Individual commitments incurred	1
IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	1,731
Individual commitments incurred	1
WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	465
Individual commitments incurred	1
DAEC (IPL) [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	1,390	[1]
DAEC (IPL) [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	1,390	[1]
DAEC (IPL) [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	0	[1]
Other [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	145	[1]
Other [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	1	[1]
Other [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	144	[1]
Purchased Power [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	1,535	[1]
Purchased Power [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	1,391	[1]
Purchased Power [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	144	[1]
Natural Gas [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	408
Natural Gas [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	225
Natural Gas [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	183
Coal [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	238	[2]
Coal [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	102	[2]
Coal [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	136	[2]
SO2 emission allowances [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	8
SO2 emission allowances [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	8
SO2 emission allowances [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	0
Other [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	24	[3]
Other [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	5	[3]
Other [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	$ 2	[3]

[1] Includes payments required by purchased power agreements for capacity rights and minimum quantities of MWhs required to be purchased.

[2] Corporate Services entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. These commitments were assigned to IPL and WPL based on information available as of March 31, 2016 regarding expected future usage, which is subject to change.

[3] Includes individual commitments incurred during the normal course of business that exceeded $1 million at March 31, 2016.