Reconciliation of Net Income/(Loss) to Net Income/(Loss) Available to Common Shareholders (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Net income/(loss)	$ 250	$ 180
Preferred dividends	(3)	(2)
Dividends and accretion of discount on preferred stock issued to the U.S. Treasury	0	(66)
Preferred Stock, Accretion of Redemption Discount	0	(74)
Dividends and undistributed earnings allocated to unvested shares	(2)	0
Net income/(loss) available to common shareholders	$ 245	$ 38
Average basic common shares	533,100,000	499,669,000
Weighted Average Number Diluted Shares Outstanding Adjustment [Abstract]
Stock options	1,000,000	1,000,000
Restricted stock	2,000,000	3,000,000
Average diluted common shares	536,407,000	503,503,000
Net income/(loss) per average common share - diluted	$ 0.46	$ 0.08
Net income/(loss) per average common share - basic	$ 0.46	$ 0.08