Fair Value (Fair Value Option - Changes in Fair Value) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Customer Resale Agreements [Member]
Gains (Losses) - FVO: Changes in Fair Value	$ (3)	$ (2)	$ (5)	$ (6)
Residential mortgage-backed agency securities with embedded derivatives [Member]
Gains (Losses) - FVO: Changes in Fair Value		(1)		13
Trading Loans [Member]
Gains (Losses) - FVO: Changes in Fair Value	1		2
Loans Held For Sale [Member] | Commercial Mortgage [Member]
Gains (Losses) - FVO: Changes in Fair Value	(13)	4	(12)	(2)
Loans Held For Sale [Member] | Residential Mortgage [Member]
Gains (Losses) - FVO: Changes in Fair Value	(48)	(287)	66	(200)
Loans - Portfolio [Member]
Gains (Losses) - FVO: Changes in Fair Value	13	(9)	19	(26)
BlackRock Series C Preferred Stock
Gains (Losses) - FVO: Changes in Fair Value		(41)	60	(10)
Other Borrowed Funds [Member]
Gains (Losses) - FVO: Changes in Fair Value	$ (3)		$ (3)