Securities Available for Sale, Unrealized Loss Position, by Credit Rating (Details) (USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010
Securities Available for Sale in an Unrealized Loss Position by Investment Grade [Abstract]
Investment Grade, Gross Unrealized Losses	$ (1,057)	$ (1,480)
Investment Grade, Fair Value	31,590	27,477
Non-Investment Grade, Gross Unrealized Losses	(878)	(1,230)
Non-Investment Grade, Fair value	7,666	7,177
Debt Securities [Member]
Securities Available for Sale in an Unrealized Loss Position by Investment Grade [Abstract]
Investment Grade, Gross Unrealized Losses	(988)	(1,399)
Investment Grade, Fair Value	30,588	26,150
Non-Investment Grade, Gross Unrealized Losses	(875)	(1,222)
Non-Investment Grade, Fair value	7,548	7,075
US Treasury and Government [Member]
Securities Available for Sale in an Unrealized Loss Position by Investment Grade [Abstract]
Investment Grade, Gross Unrealized Losses	(13)	(15)
Investment Grade, Fair Value	7,267	544
Non-Investment Grade, Gross Unrealized Losses	0	0
Non-Investment Grade, Fair value	0	0
US States and Political Subdivisions [Member]
Securities Available for Sale in an Unrealized Loss Position by Investment Grade [Abstract]
Investment Grade, Gross Unrealized Losses	(467)	(722)
Investment Grade, Fair Value	8,340	8,423
Non-Investment Grade, Gross Unrealized Losses	(96)	(115)
Non-Investment Grade, Fair value	473	539
Mortgage Backed Securities [Member]
Securities Available for Sale in an Unrealized Loss Position by Investment Grade [Abstract]
Investment Grade, Gross Unrealized Losses	(279)	(418)
Investment Grade, Fair Value	9,551	13,730
Non-Investment Grade, Gross Unrealized Losses	(561)	(802)
Non-Investment Grade, Fair value	5,770	5,478
Federal agencies [Member]
Securities Available for Sale in an Unrealized Loss Position by Investment Grade [Abstract]
Investment Grade, Gross Unrealized Losses	(26)	(96)
Investment Grade, Fair Value	4,721	8,163
Non-Investment Grade, Gross Unrealized Losses	0	0
Non-Investment Grade, Fair value	0	0
Residential [Member]
Securities Available for Sale in an Unrealized Loss Position by Investment Grade [Abstract]
Investment Grade, Gross Unrealized Losses	(14)	(23)
Investment Grade, Fair Value	544	888
Non-Investment Grade, Gross Unrealized Losses	(304)	(466)
Non-Investment Grade, Fair value	4,778	4,575
Commercial [Member]
Securities Available for Sale in an Unrealized Loss Position by Investment Grade [Abstract]
Investment Grade, Gross Unrealized Losses	(239)	(299)
Investment Grade, Fair Value	4,286	4,679
Non-Investment Grade, Gross Unrealized Losses	(257)	(336)
Non-Investment Grade, Fair value	992	903
Corporate debt securities [Member]
Securities Available for Sale in an Unrealized Loss Position by Investment Grade [Abstract]
Investment Grade, Gross Unrealized Losses	(18)	(22)
Investment Grade, Fair Value	839	330
Non-Investment Grade, Gross Unrealized Losses	(57)	(15)
Non-Investment Grade, Fair value	679	304
Collateralized debt obligations [Member]
Securities Available for Sale in an Unrealized Loss Position by Investment Grade [Abstract]
Investment Grade, Gross Unrealized Losses	(47)	(42)
Investment Grade, Fair Value	2,069	613
Non-Investment Grade, Gross Unrealized Losses	(139)	(187)
Non-Investment Grade, Fair value	365	522
Other Debt Securities [Member]
Securities Available for Sale in an Unrealized Loss Position by Investment Grade [Abstract]
Investment Grade, Gross Unrealized Losses	(164)	(180)
Investment Grade, Fair Value	2,522	2,510
Non-Investment Grade, Gross Unrealized Losses	(22)	(103)
Non-Investment Grade, Fair value	261	232
Perpetual preferred securities [Member]
Securities Available for Sale in an Unrealized Loss Position by Investment Grade [Abstract]
Investment Grade, Gross Unrealized Losses	(69)	(81)
Investment Grade, Fair Value	1,002	1,327
Non-Investment Grade, Gross Unrealized Losses	(3)	(8)
Non-Investment Grade, Fair value	$ 118	$ 102