Trading Assets and Liabilities (Details) - USD ($) $ in Millions		Sep. 30, 2016	Dec. 31, 2015
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		$ 19,586	$ 17,085
Trading liabilities		7,537	7,455
U.S. Treasury [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		4,374	3,088
US Government agency issued or guaranteed [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		11	13
US Government sponsored enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	[1]	169	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		374	424
Corporate and foreign bonds [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		8,300	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		2,669	780
Trading liabilities		49	650
Securities sold, not yet purchased [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading liabilities		1,030	399
Derivatives [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		3,674	5,150
Derivatives [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading liabilities		6,458	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		142	$ 154
Federal Home Loan Mortgage Corporation Certificates and Obligations (FHLMC) [Member] | US Government sponsored enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		$ 27

[1] Consists of mortgage backed securities of $142 million and $154 million issued or guaranteed by the Federal National Mortgage Association ("FNMA") at September 30, 2016 and December 31, 2015, respectively, and $27 million issued or guaranteed by the Federal Home Loan Mortgage Corporation ("FHLMC") at September 30, 2016.