Commitments and Guarantees - Narrative (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Loss Contingencies [Line Items]
Unfunded commitments to extend credit, short term	73.00%
Term of unfunded commitment	1 year
Cash collateral provided for securities lending	$ 23,630	$ 21,200
Accrued expenses and other liabilities
Loss Contingencies [Line Items]
Cash collateral received in connection to securities finance activities	$ 5,270	$ 5,020