Commitments and Guarantees - Contractual Amounts of Credit-Related Off-Balance Sheet Financial Instruments (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Unfunded credit facilities	$ 34,471	$ 34,213
Indemnified securities financing	402,369	440,875
Standby letters of credit	$ 3,333	$ 3,330
Unfunded commitments to extend credit, short term	73.00%	73.00%
Term of unfunded commitment	1 year	1 year