Derivative Financial Instruments Netting of Financial Instruments - Derivatives (Additional Information) (Details) - USD ($) $ in Millions		Mar. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Derivative Assets	[1]	$ 1,735	$ 1,152
Derivative Asset, Collateral, Obligation to Return Cash, Offset		607	397
Derivative Liabilities	[2]	654	464
Derivative Liability, Collateral, Right to Reclaim Cash, Offset		1,273	1,048
Trading Securities [Member]
Derivative [Line Items]
Derivative Assets		1,735	1,152
Trading Liabilities [Member]
Derivative [Line Items]
Derivative Liabilities		$ 654	$ 464

[1] At March 31, 2016, $1.7 billion, net of $607 million offsetting cash collateral, is recognized in trading assets and derivative instruments within the Company's Consolidated Balance Sheets. At December 31, 2015, $1.2 billion, net of $397 million offsetting cash collateral, is recognized in trading assets and derivative instruments within the Company's Consolidated Balance Sheets.

[2] At March 31, 2016, $654 million, net of $1.3 billion offsetting cash collateral, is recognized in trading liabilities and derivative instruments within the Company's Consolidated Balance Sheets. At December 31, 2015, $464 million, net of $1.0 billion offsetting cash collateral, is recognized in trading liabilities and derivative instruments within the Company's Consolidated Balance Sheets.