Stockholder's Equity (Details 1) (USD $) Share data in Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012 Number of Common shares Issued [Member]	Mar. 31, 2011 Number of Common shares Issued [Member]	Mar. 31, 2012 Number of Common shares Treasury [Member]	Mar. 31, 2011 Number of Common shares Treasury [Member]	Mar. 31, 2012 Common Stockholders' Equity [Member]	Mar. 31, 2011 Common Stockholders' Equity [Member]	Mar. 31, 2012 Preferred and Preference Stock of Subsidiaries [Member]	Dec. 31, 2011 Preferred and Preference Stock of Subsidiaries [Member]	Mar. 31, 2011 Preferred and Preference Stock of Subsidiaries [Member]	Dec. 31, 2010 Preferred and Preference Stock of Subsidiaries [Member]
Changes in Stockholders' Equity
Beginning Balance	$ 18,285,000,000	$ 16,909,000,000					$ 17,578,000,000	$ 16,202,000,000	$ 707,000,000	$ 707,000,000	$ 707,000,000	$ 707,000,000
Beginning Balance, Shares			(865,664)	(843,814)	(539)	(474)
Net Income After Dividends on Preferred and Preference Stock	368,000,000	422,000,000					368,000,000	422,000,000
Other comprehensive income (loss)	6,000,000	4,000,000					6,000,000	4,000,000
Stock issued, shares			3,571	5,784
Stock issued	157,000,000	222,000,000					157,000,000	222,000,000
Cash dividends on common stock	(410,000,000)	(385,000,000)					(410,000,000)	(385,000,000)
Other, shares					(6)	(1)
Ending Balance	$ 18,406,000,000	$ 17,172,000,000					$ 17,699,000,000	$ 16,465,000,000	$ 707,000,000	$ 707,000,000	$ 707,000,000	$ 707,000,000
Ending Balance, Shares			(869,235)	(849,598)	(545)	(475)