Fair Value (Fair Value Option - Changes in Fair Value) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Loans Held For Sale [Member] | Commercial Mortgage [Member]
Gains (Losses) - FVO: Changes in Fair Value	$ 22	$ 31	$ 49	$ 56
Loans Held For Sale [Member] | Residential Mortgage [Member]
Gains (Losses) - FVO: Changes in Fair Value	59	25	106	71
Loans - Portfolio [Member] | Residential Mortgage [Member]
Gains (Losses) - FVO: Changes in Fair Value	11	13	17	29
BlackRock Series C Preferred Stock
Gains (Losses) - FVO: Changes in Fair Value	1	(21)	(10)	(12)
Other Assets [Member]
Gains (Losses) - FVO: Changes in Fair Value	$ (4)	1	$ (20)	2
Other borrowed funds [Member]
Gains (Losses) - FVO: Changes in Fair Value		$ (2)		$ (2)