Commitments and Guarantees - Contractual Amounts of Credit-Related Off-Balance Sheet Financial Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Unfunded credit facilities	$ 33,736	$ 29,697
Indemnified securities financing	379,052	367,901
Standby letters of credit	$ 3,240	$ 3,324
Unfunded Commitments Set to Expire	73.00%