Stockholders' Equity - Changes in Stockholders' Equity (Details) (USD $) Share data in Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Changes in Stockholders' Equity
Beginning Balance	$ 19,764,000,000		$ 19,004,000,000
Net Income After Dividends on Preferred and Preference Stock	(351,000,000)	[1],[2]	(81,000,000)	[1]
Other comprehensive income (loss)	2,000,000		4,000,000
Stock Issued During Period, Value, Treasury Stock Reissued	111,000,000
Stock issued	53,000,000		99,000,000
Stock Repurchased During Period, Value	(4,000,000)		(18,000,000)
Cash dividends on common stock	(451,000,000)		(426,000,000)
Other	0		0
Ending Balance	19,826,000,000		18,744,000,000
Number of Common shares Issued [Member]
Changes in Stockholders' Equity
Beginning Balance, Shares	(892,733)		(877,803)
Stock issued, shares	1,340		2,638
Stock Repurchased During Period, Shares	0		0
Ending Balance, Shares	(894,073)		(880,441)
Number of Common shares Treasury [Member]
Changes in Stockholders' Equity
Beginning Balance, Shares	(5,647)		(10,035)
Stock Issued During Period, Shares, Treasury Stock Reissued	2,404
Stock Repurchased During Period, Shares	0		0
Other, Shares	(18)		(15)
Ending Balance, Shares	(3,261)		(10,050)
Common Stockholders' Equity [Member]
Changes in Stockholders' Equity
Beginning Balance	19,008,000,000		18,297,000,000
Net Income After Dividends on Preferred and Preference Stock	351,000,000		(81,000,000)
Other comprehensive income (loss)	2,000,000		4,000,000
Stock Issued During Period, Value, Treasury Stock Reissued	111,000,000
Stock issued	53,000,000		99,000,000
Stock Repurchased During Period, Value	(4,000,000)		(18,000,000)
Cash dividends on common stock	(451,000,000)		(426,000,000)
Other	0		0
Ending Balance	19,070,000,000		18,037,000,000
Preferred and Preference Stock of Subsidiaries [Member]
Changes in Stockholders' Equity
Beginning Balance	756,000,000		707,000,000
Net Income After Dividends on Preferred and Preference Stock	0		0
Other comprehensive income (loss)	0		0
Stock issued	0		0
Stock Repurchased During Period, Value	0		0
Cash dividends on common stock	0
Other	0		0
Ending Balance	$ 756,000,000		$ 707,000,000

[1] After dividends on preferred and preference stock of subsidiaries.

[2] Segment net income (loss) for the traditional operating companies for the three months ended March 31, 2014 includes a $380.0 million pre-tax charge ($234.7 million after tax) for an estimated probable loss on the Kemper IGCC. See Note (B) under "Integrated Coal Gasification Combined Cycle – Kemper IGCC Schedule and Cost Estimate" herein for additional information.