Subsequent Events (Details) (USD $)	3 Months Ended		57 Months Ended	0 Months Ended	1 Months Ended	58 Months Ended	3 Months Ended	0 Months Ended	1 Months Ended	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Apr. 23, 2015	May 08, 2015	May 08, 2015	Jun. 30, 2015	Mar. 07, 2014	Apr. 30, 2015	Dec. 31, 2014	Apr. 08, 2015	Apr. 06, 2015	Apr. 01, 2015
Subsequent Event [Line Items]
Common Stock, Dividends, Per Share, Declared	$ 0.00	$ 0.00
Treasury Stock, Value, Acquired, Cost Method	$ 35,000,000	$ 0	$ 1,300,000,000
Treasury Stock, Shares, Acquired	2,816,493		108,728,970
Treasury Stock Acquired, Average Cost Per Share			$ 12.37
Stock Repurchase Program, Remaining Authorized Repurchase Amount	388,000,000		388,000,000
Gains (Losses) on Extinguishment of Debt	(23,000,000)	(134,000,000)
Maritza [Member]
Subsequent Event [Line Items]
Overdue Maritza Receivables	236,000,000		236,000,000
Subsequent Event [Member]
Subsequent Event [Line Items]
Common Stock, Dividends, Per Share, Declared				$ 0.10
Treasury Stock, Value, Acquired, Cost Method					7,000,000	1,400,000,000
Treasury Stock, Shares, Acquired					591,028	109,319,998
Treasury Stock Acquired, Average Cost Per Share						$ 12.38
Stock Repurchase Program, Remaining Authorized Repurchase Amount					381,000,000	381,000,000
Subsequent Event [Member] | Maritza [Member]
Subsequent Event [Line Items]
Capacity Payment reduction percentage											14.00%
Recourse Debt [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Gains (Losses) on Extinguishment of Debt							82,000,000
5.50% senior notes due 2025 [Domain] | Recourse Debt [Member]
Subsequent Event [Line Items]
Issued new debt												575,000,000
Debt Instrument, Interest Rate, Stated Percentage												5.50%
8.0% Senior Notes Due 2017 [Member] | Recourse Debt [Member]
Subsequent Event [Line Items]
Debt Instrument, Interest Rate, Stated Percentage								8.00%
Extinguishment of Debt, Amount								625,000,000
Gains (Losses) on Extinguishment of Debt								(132,000,000)
8.0% Senior Notes Due 2017 [Member] | Recourse Debt [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Debt Instrument, Interest Rate, Stated Percentage												8.00%
Extinguishment of Debt, Amount									344,000,000
8.00% Senior Unsecured Note Due 2020 [Member] | Recourse Debt [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Debt Instrument, Interest Rate, Stated Percentage												8.00%
Extinguishment of Debt, Amount									156,000,000
IPALCO Enterprises, Inc. [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
sales agreement, Buyer option to purchase ownership interest, exercised													214,000,000
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners													24.90%
IPALCO Enterprises, Inc. [Member] | Subsequent Event [Member] | Acquire additional shares through 2016 [Member]
Subsequent Event [Line Items]
Sale Agreement, Buyer Option To Purchase Ownership Interest, Sales Price										$ 349,000,000