Trading Assets and Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	$ 33,520	$ 16,850
Trading liabilities	4,084	4,908
U.S. Treasury [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	4,250	3,560
US Government agency issued or guaranteed [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	125	24
US Government sponsored enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	213	222
Asset backed securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	288	365
Corporate and foreign bonds [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	6,130	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	19,124	1,772
Trading liabilities	0	62
Securities sold, not yet purchased [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading liabilities	1,474	1,060
Derivatives [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	3,378	4,411
Derivatives [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading liabilities	$ 2,610	$ 3,786