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		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Net income/(loss)	$ 275	$ 178	$ 525	$ 358
Preferred dividends	(3)	(2)	(6)	(4)
Dividends and accretion of discount on preferred stock issued to the U.S. Treasury	0	0	0	(66)
Preferred Stock, Accretion of Redemption Discount	0	0	0	(74)
Dividends and undistributed earnings allocated to unvested shares	(2)	2	(4)	2
Net income/(loss) available to common shareholders	$ 270	$ 174	$ 515	$ 212
Average basic common shares	533,964,000	531,792,000	533,532,000	515,819,000
Weighted Average Number Diluted Shares Outstanding Adjustment [Abstract]
Stock options	1,000,000	1,000,000	1,000,000	2,000,000
Restricted stock	2,000,000	2,000,000	2,000,000	2,000,000
Average diluted common shares	537,495,000	535,416,000	536,951,000	519,548,000
Net income/(loss) per average common share - diluted	$ 0.50	$ 0.33	$ 0.96	$ 0.41
Net income/(loss) per average common share - basic	$ 0.51	$ 0.33	$ 0.97	$ 0.41