Trading Assets and Liabilities (Details) - USD ($) $ in Millions		Mar. 31, 2016	Dec. 31, 2015
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		$ 18,266	$ 17,085
Trading liabilities		8,788	7,455
U.S. Treasury [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		3,646	3,088
US Government agency issued or guaranteed [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		12	13
US Government sponsored enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	[1]	154	154
Obligations of U.S. states and political subdivision [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		550	559
Asset backed securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		404	424
Corporate and foreign bonds [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		7,185	6,899
Other securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		14	18
Precious metals [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		1,194	780
Trading liabilities		241	650
Securities sold, not yet purchased [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading liabilities		654	399
Derivatives [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		5,107	5,150
Derivatives [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading liabilities		7,893	6,406
Federal National Mortgage Association Certificates and Obligations (FNMA) [Member] | US Government sponsored enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		$ 154	$ 154

[1] Consists of mortgage backed securities of $154 million issued or guaranteed by the Federal National Mortgage Association ("FNMA") at both March 31, 2016 and December 31, 2015.