Capital Actions - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	6 Months Ended	1 Months Ended		1 Months Ended			1 Months Ended
	Jun. 30, 2011	Jan. 31, 2011 Group 1	Jan. 24, 2011 Group 2	Feb. 04, 2011 Group 5	Feb. 02, 2011 Retained Earnings	Jun. 30, 2011 Trust Preferred Securities	Feb. 02, 2011 Preferred stock Series F	Mar. 16, 2011 Preferred stock Series F	Dec. 31, 2010 Preferred stock Series F	Jun. 30, 2010 Preferred stock Series F
Common stock issued, value	$ 1,648	$ 1,700
Common stock issued, shares		121,428,572	12,142,857
Common stock, market price		$ 14.00	$ 14.00
Forward sale agreement				959,821
Preferred shares repurchased							136,320
Accretion from redemption, Series F					153
Repurchase of warrants								280
Capital surplus, shares of common stock to purchase								43,617,747	43,617,747	43,617,747
Capital surplus, initial exercise price								11.72	11.72	11.72
Principal balances of redeemed trust preferred securities, at par, classified as long-term debt						$ 452