Trading Assets and Liabilities (Details) - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		$ 17,085	$ 21,092
Trading liabilities		7,455	8,164
U.S. Treasury [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		3,088	2,675
US Government agency issued or guaranteed [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		13	3
US Government sponsored enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	[1]	154	45
Obligations of U.S. states and political subdivision [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		559	591
Asset backed securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		424	481
Corporate and foreign bonds [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		6,899	9,681
Other securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		18	22
Precious metals [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		780	1,992
Trading liabilities		650	22
Securities sold, not yet purchased [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading liabilities		399	683
Derivatives [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets		5,150	5,602
Derivatives [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading liabilities		6,406	7,459
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	$ 45

[1] Consists of mortgage backed securities of $154 million and $45 million issued or guaranteed by the Federal National Mortgage Association ("FNMA") at December 31, 2015 and 2014, respectively.