Commitments And Contingencies (Operating Expense Purchase Obligations) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2016 USD ($)
Commitments and Contingencies [Line Items]
Minimum future commitments	$ 2,238
Individual commitments incurred	1
IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	1,649
Individual commitments incurred	1
WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	573
Individual commitments incurred	1
DAEC (IPL) [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	1,320	[1]
DAEC (IPL) [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	1,320	[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	139	[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	138	[1]
Purchased Power [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	1,459	[1]
Purchased Power [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	1,321	[1]
Purchased Power [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	138	[1]
Natural gas [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	557
Natural gas [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	231
Natural gas [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	326
Coal [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	193	[2]
Coal [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	85	[2]
Coal [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	108	[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	21	[3]
Other [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	4	[3]
Other [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	$ 1	[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 September 30, 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 September 30, 2016.