Trading Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	$ 16,850	$ 17,085
Trading liabilities	4,908	7,455
U.S. Treasury [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	3,560	3,088
US Government agency issued or guaranteed [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	24	13
US Government sponsored enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	222	154
Obligations of U.S. states and political subdivision [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	0	559
Asset backed securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	365	424
Corporate and foreign bonds [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	6,481	6,899
Other securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	15	18
Precious metals [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	1,772	780
Trading liabilities	62	650
Securities sold, not yet purchased [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading liabilities	1,060	399
Derivatives [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	4,411	5,150
Derivatives [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading liabilities	$ 3,786	$ 6,406