Commitments and Guarantees - Narrative (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Loss Contingencies [Line Items]
Unfunded commitments to extend credit	$ 23,320	$ 24,430
Unfunded commitments to extend credit, short term	75.00%
Unfunded Commitment to Extend Credit, Term	1 year
Cash collateral provided for securities lending	$ 21,950	15,940
Accrued expenses and other liabilities
Loss Contingencies [Line Items]
Cash collateral received in connection to securities finance activities	$ 4,240	$ 6,480