Commitments And Contingencies (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) site
Long-term Purchase Commitment [Line Items]
Minimum future commitments	$ 2,292
Time frame for plaintiffs to seek appeal of decision	30 days
Performance guarantees outstanding	$ 123
Present value abandonment obligation	$ 28
Minimum [Member]
Long-term Purchase Commitment [Line Items]
Warranty period	12 months
Maximum [Member]
Long-term Purchase Commitment [Line Items]
Warranty period	60 months
Performance guarantees outstanding, 2016 [Member]
Long-term Purchase Commitment [Line Items]
Performance guarantees outstanding	$ 48
Performance guarantees outstanding, 2017 [Member]
Long-term Purchase Commitment [Line Items]
Performance guarantees outstanding	75
Capital Purchase Obligation [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments	23
DAEC IPL [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments	1,419	[1],[2]
IPL [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments	1,792
Maximum indemnification limit	$ 17
Number of sites monitoring and/or remediating (in sites) | site	24
IPL [Member] | Capital Purchase Obligation [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments	$ 7
WPL [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments	$ 482
Number of sites monitoring and/or remediating (in sites) | site	5
WPL [Member] | Capital Purchase Obligation [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments	$ 16
Environmental Issue [Member] | IPL [Member]
Long-term Purchase Commitment [Line Items]
Damages awarded	6
Environmental Issue [Member] | WPL [Member]
Long-term Purchase Commitment [Line Items]
Damages awarded	7
Civil Penalty [Member] | IPL [Member]
Long-term Purchase Commitment [Line Items]
Damages awarded	$ 1

[1] Includes commitments incurred under a PPA, which grants IPL rights to purchase up to 431 MWs of capacity and the resulting energy from DAEC for a term through December 31, 2025. If energy delivered is less than the targeted energy amount, an adjustment payment will be made to IPL, which will be reflected in IPL’s fuel adjustment clause.

[2] Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased. Refer to Note 18 for additional information on purchased power transactions.