Long-Term Debt and Capital - Additional Information (Detail) (USD $) Share data in Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2011		Mar. 31, 2011	Sep. 30, 2010	Sep. 30, 2011		Sep. 30, 2010	Dec. 31, 2010
Common stock offerings			$ 1,000,000,000		$ 1,017,000,000
Senior notes, issuance interest rate			3.60%
Senior notes, due date			2016
Repurchase of Fixed Rate Cumulative Preferred Stock, series C					4,850,000,000
Repurchase of Series C & D preferred stock, accelerating the outstanding discount accretion	0			0	(74,000,000)		0
Purchase of outstanding warrants					11,000,000		0
Debt issued	13,544,000,000	[1]			13,544,000,000	[1]		13,648,000,000	[1]
Subordinated debt matured					852,000,000
Floating rate euro denominated notes, repayment					320,000,000
Common stock offerings, increase in common equity					1,800,000,000
Transactions that decreased common equity					2,900,000,000
Senior Notes
Senior notes, due date			1,000,000,000
Additional Paid in Capital
Common stock offerings					982,000,000
Purchase of outstanding warrants					11,000,000
Series C Preferred Stock
Repurchase of Fixed Rate Cumulative Preferred Stock, series C			3,500,000,000
Series D Preferred Stock
Repurchase of Fixed Rate Cumulative Preferred Stock, series C			1,400,000,000
Series C and Series D Preferred Stock
Repurchase of Series C & D preferred stock, accelerating the outstanding discount accretion			74,000,000
Warrants [Member]
Class of Warrant or Right, Outstanding	17.9				17.9
Group 1
Warrant issued to purchase common stock, shares	11.9				11.9
Warrant issued, initial exercise price	44.15				44.15
Group 2
Warrant issued to purchase common stock, shares	6.0				6.0
Warrant issued, initial exercise price	$ 33.70				$ 33.70
warrants purchased					4

[1] Includes debt of consolidated VIEs ($285 and $290 at fair value at September 30, 2011 and December 31, 2010, respectively) $728 $764