Preferred Stock (Details) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2011	Apr. 15, 2011	Dec. 31, 2010
Carrying amount of each outstanding series of Company's preferred stock
Shares Issued and Outstanding	72,510		65,746
Liquidation Preference	$ 2,751		$ 2,075
Discount	145		145
Carrying Amount	2,606		1,930
Preferred Stock (Textual) [Abstract]
Preferred stock shares authorized	50,000,000		50,000,000
Par value of shares issued and outstanding	$ 1.00		$ 1.00
Series A
Carrying amount of each outstanding series of Company's preferred stock
Shares Issued and Outstanding	12,510		5,746
Liquidation Preference	1,251		575
Discount	145		145
Carrying Amount	1,106		430
Preferred Stock (Textual) [Abstract]
Depositary shares issued representing an ownership interest		6,764
Liquidation preference per share		$ 100,000
Preferred stock, dividend rate, variable percentage	Three-month LIBOR plus 1.02 percent
Preferred stock, dividend rate, fixed percentage	3.50%
Series B
Carrying amount of each outstanding series of Company's preferred stock
Shares Issued and Outstanding	40,000		40,000
Liquidation Preference	1,000		1,000
Carrying Amount	1,000		1,000
Series D
Carrying amount of each outstanding series of Company's preferred stock
Shares Issued and Outstanding	20,000		20,000
Liquidation Preference	500		500
Carrying Amount	$ 500		$ 500