Fair Value (Fair Value Option - Changes in Fair Value) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Loans Held For Sale [Member] | Commercial Mortgage [Member]
Gains (Losses) - FVO: Changes in Fair Value	$ 27	$ 25
Loans Held For Sale [Member] | Residential Mortgage [Member]
Gains (Losses) - FVO: Changes in Fair Value	47	46
Loans - Portfolio [Member] | Residential Mortgage [Member]
Gains (Losses) - FVO: Changes in Fair Value	6	16
BlackRock Series C Preferred Stock
Gains (Losses) - FVO: Changes in Fair Value	(11)	9
Other Assets [Member]
Gains (Losses) - FVO: Changes in Fair Value	$ (16)	$ 1