Commitments and Guarantees - Contractual Amounts of Credit-Related Off-Balance Sheet Financial Instruments (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Unfunded credit facilities	$ 29,681	$ 28,951
Indemnified securities financing	386,978	342,337
Standby letters of credit	$ 3,307	$ 2,985
Unfunded commitments to extend credit, short term	74.00%
Term of unfunded commitment	1 year