Stockholders' Equity - Changes in Stockholders' Equity (Details) (USD $) Share data in Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Changes in Stockholders' Equity
Beginning Balance					$ 19,764,000,000		$ 19,004,000,000
Net Income After Dividends on Preferred and Preference Stock	611,000,000	[1],[2]	297,000,000	[1],[2]	962,000,000	[1],[3]	378,000,000	[1],[3]
Other comprehensive income (loss)					4,000,000		9,000,000
Stock Issued During Period, Value, Treasury Stock Reissued					216,000,000
Stock issued					161,000,000		293,000,000
Stock Repurchased During Period, Value					(5,000,000)		(18,000,000)
Cash dividends on common stock					(920,000,000)		(870,000,000)
Other					0		0
Ending Balance	20,182,000,000		18,796,000,000		20,182,000,000		18,796,000,000
Number of Common shares Issued [Member]
Changes in Stockholders' Equity
Beginning Balance, Shares					892,733		877,803
Stock issued, shares					3,898		6,144
Stock Repurchased During Period, Shares					0		0
Ending Balance, Shares	896,631		883,947		896,631		883,947
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					4,739
Stock Repurchased During Period, Shares					0		0
Other, Shares					(27)		(9)
Ending Balance, Shares	935		10,044		935		10,044
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					962,000,000		378,000,000
Other comprehensive income (loss)					4,000,000		9,000,000
Stock Issued During Period, Value, Treasury Stock Reissued					216,000,000
Stock issued					161,000,000		244,000,000
Stock Repurchased During Period, Value					(5,000,000)		(18,000,000)
Cash dividends on common stock					(920,000,000)		(870,000,000)
Other					0		0
Ending Balance	19,426,000,000		18,040,000,000		19,426,000,000		18,040,000,000
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 During Period, Value, Treasury Stock Reissued					0
Stock issued					0		49,000,000
Stock Repurchased During Period, Value					0		0
Cash dividends on common stock					0		0
Other					0		0
Ending Balance	$ 756,000,000		$ 756,000,000		$ 756,000,000		$ 756,000,000

[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 June 30, 2013 includes a $450.0 million pre-tax charge ($277.9 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.

[3] Segment net income (loss) for the traditional operating companies for the six months ended June 30, 2014 and June 30, 2013 includes $380.0 million in pre-tax charges ($234.7 million after tax) and $990.0 million in pre-tax charges ($611.3 million after tax), respectively, for estimated probable losses on the Kemper IGCC. See Note (B) under "Integrated Coal Gasification Combined Cycle – Kemper IGCC Schedule and Cost Estimate" herein for additional information.