Fair Value (Fair Value Option - Changes in Fair Value) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Customer Resale Agreements [Member]
Gains (Losses) - FVO: Changes in Fair Value				$ (1)
Trading Loans [Member]
Gains (Losses) - FVO: Changes in Fair Value	$ 1	$ 1	$ 2	1
Loans Held For Sale [Member] | Commercial Mortgage [Member]
Gains (Losses) - FVO: Changes in Fair Value	31	5	56	7
Loans Held For Sale [Member] | Residential Mortgage [Member]
Gains (Losses) - FVO: Changes in Fair Value	25	64	71	129
Loans - Portfolio [Member] | Residential Mortgage [Member]
Gains (Losses) - FVO: Changes in Fair Value	13	59	29	87
BlackRock Series C Preferred Stock
Gains (Losses) - FVO: Changes in Fair Value	(21)	5	(12)	3
Other Borrowed Funds [Member]
Gains (Losses) - FVO: Changes in Fair Value	$ (2)	$ 7	$ (2)	$ 3