Fair Value (Fair Value Option - Changes in Fair Value) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Customer Resale Agreements [Member]
Gains (Losses) - FVO: Changes in Fair Value	$ (1)	[1]	$ 1	[1]	$ (7)	[1]	$ (6)	[1]
Residential mortgage-backed agency securities with embedded derivatives [Member]
Gains (Losses) - FVO: Changes in Fair Value		[1],[2]	27	[1],[2]	13	[1],[2]	24	[1],[2]
Commercial Mortgage Loans Held for Sale [Member]
Gains (Losses) - FVO: Changes in Fair Value	(2)	[1]	4	[1]	(4)	[1]	3	[1]
Residential Mortgage Loans Held For Sale [Member]
Gains (Losses) - FVO: Changes in Fair Value	147	[1]	77	[1]	(53)	[1]	185	[1]
Residential Mortgage Loans - Portfolio [Member]
Gains (Losses) - FVO: Changes in Fair Value	(8)	[1]	(16)	[1]	(34)	[1]	(14)	[1]
Black Rock Series C Preferred Stock [Member]
Gains (Losses) - FVO: Changes in Fair Value	$ 10	[1]	$ (80)	[1]			$ (50)	[1]

[1] The impact on earnings of offsetting hedged items or hedging instruments is not reflected in these amounts.

[2] These residential mortgage-backed agency securities with embedded derivatives were carried as Trading securities.