Offsetting Arrangements - Assets With Enforceable Netting Arrangements (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Offsetting [Abstract]
Derivative, Net Amount of Assets Presented in Statement of Condition	$ 5,387	$ 7,934
Derivatives, Counterparty Netting	0	0
Derivatives, Collateral Received	(410)	(1,490)
Derivatives, Net Amount	4,977	6,444
Resale Agreements and Securities Borrowing, Resale Agreements and Securities Borrowing, Net Amount of Assets Presented in Statement of Condition	30,360	18,331
Resale Agreements and Securities Borrowing, Counterparty Netting	(48)	(128)
Resale Agreements and Securities Borrowing, Collateral Received	(29,780)	(18,157)
Resale Agreements and Securities Borrowing, Net Amount	532	46
Total, Net Amounts of Assets Presented in Statement of Condition	35,747	26,265
Total, Counterparty Netting	(48)	(128)
Total, Collateral Received	(30,190)	(19,647)
Total, Net Amount	$ 5,509	$ 6,490