Fair Value (Fair Value Option - Changes in Fair Value) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011
Customer Resale Agreements [Member]
Gains (losses) on fair value option	$ (2)	[1]	$ 1	[1]	$ (6)	[1]	$ (7)	[1]
Residential mortgage-backed agency securities with embedded derivatives [Member]
Gains (losses) on fair value option	(1)	[1],[2]	(3)	[1],[2]	13	[1],[2]	(3)	[1],[2]
Commercial Mortgage Loans Held for Sale [Member]
Gains (losses) on fair value option	4	[1]	6	[1]	(2)	[1]	(1)	[1]
Residential Mortgage Loans Held For Sale [Member]
Gains (losses) on fair value option	(287)	[1]	60	[1]	(200)	[1]	108	[1]
Residential Mortgage Loans - Portfolio [Member]
Gains (losses) on fair value option	(9)	[1]	(8)	[1]	(26)	[1]	2	[1]
Black Rock Series C Preferred Stock [Member]
Gains (losses) on fair value option	$ (41)	[1]	$ (21)	[1]	$ (10)	[1]	$ 30	[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.