Reconciliation of Net Income/(Loss) to Net Income/(Loss) Available to Common Shareholders (Detail) (USD $) In Millions, except Share data	3 Months Ended				9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2011		Sep. 30, 2010
Net income/(loss)	$ 215		$ 153		$ 573		$ 5
Series A preferred dividends	(2)		(2)		(5)		(6)
Dividends and accretion of discount on preferred stock issued to the U.S. Treasury	0		(67)		(66)		(200)
Accelerated accretion for repurchase of preferred stock issued to the U.S. Treasury	0		0		(74)		0
Dividends and undistributed earnings allocated to unvested shares	(2)		0		(4)		0
Net income/(loss) available to common shareholders	$ 211		$ 84		$ 424		$ (201)
Average basic common shares	531,928,000		495,501,000		521,248,000		495,243,000
Weighted Average Number Diluted Shares Outstanding Adjustment [Abstract]
Stock options	1,000,000		1,000,000		2,000,000		1,000,000
Restricted stock	2,000,000		2,000,000		2,000,000		2,000,000
Average diluted common shares	535,395,000		498,802,000		524,888,000		498,515,000
Net income/(loss) per average common share - diluted	$ 0.39	[1]	$ 0.17	[1]	$ 0.81	[1]	$ (0.41)	[2]
Net income/(loss) per average common share - basic	$ 0.40		$ 0.17		$ 0.81		$ (0.41)

[1] For earnings per share calculation purposes, the impact of dilutive securities are excluded from the diluted share count during periods that the Company has recognized a net loss available to common shareholders because the impact would be anti-dilutive.

[2] Change in unrealized gains/(losses) included in earnings during the period related to financial assets still held at September 30, 2011.