Trading Assets and Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	$ 20,192	$ 16,850
Trading liabilities	4,209	4,908
U.S. Treasury [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	4,610	3,560
US Government agency issued or guaranteed [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	23	24
US Government sponsored enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	211	222
Asset backed securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	303	365
Corporate and foreign bonds [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	3,446	6,481
Other securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	12	15
Precious metals [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	8,365	1,772
Trading liabilities	0	62
Securities sold, not yet purchased [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading liabilities	1,021	1,060
Derivatives [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	3,222	4,411
Derivatives [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading liabilities	$ 3,188	$ 3,786