Offsetting Arrangements - Assets With Offsetting Arrangements (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Offsetting Assets [Line Items]
Derivatives, Gross Amounts of Recognized Assets	$ 16,457	$ 25,944
Derivatives, Gross Amounts Offset in Statement of Condition	(8,892)	(20,140)
Derivatives, Net Amounts of Assets Presented in Statement of Condition	7,565	5,804
Derivatives, Net Amount	6,479	4,699
Derivatives, Cash collateral and securities netting, cash offset	(1,225)	(5,869)
Derivatives, Cash collateral and securities netting, Cash and Securities Received	(1,086)	(1,105)
Derivatives, Cash collateral and securities netting, Net Amount	(2,311)	(6,974)
Resale agreements and securities borrowing, Gross Amounts of Recognized Assets	87,099	174,461
Resale agreements and securities borrowing, Gross Amounts Offset in Statement of Condition	(57,609)	(153,025)
Resale agreements and securities borrowing, Net Amounts of Assets Presented in Statement of Condition	29,490	21,436
Resale agreements and securities borrowing, Cash and Securities Received	(29,242)	(20,568)
Resale agreements and securities borrowing, Net Amount	248	868
Total derivatives and other financial instruments, Gross Amounts of Recognized Assets	103,556	200,405
Total derivatives and other financial instruments, Gross Amounts Offset in Statement of Condition	(66,501)	(173,165)
Total derivatives and other financial instruments, Net Amounts of Assets Presented in Statement of Condition	37,055	27,240
Total derivatives and other financial instruments, Cash and Securities Received	(30,328)	(21,673)
Total derivatives and other financial instruments, Net Amount	6,727	5,567
Securities purchased under resale agreements	2,847	3,106
Cash collateral provided for securities borrowing	26,640	18,330
Foreign exchange contracts
Offsetting Assets [Line Items]
Derivatives, Gross Amounts of Recognized Assets	16,453	25,943
Derivatives, Gross Amounts Offset in Statement of Condition	(7,667)	(14,271)
Derivatives, Net Amounts of Assets Presented in Statement of Condition	8,786	11,672
Derivatives, Net Amount	8,786	11,672
Interest rate contracts
Offsetting Assets [Line Items]
Derivatives, Gross Amounts of Recognized Assets	4	1
Derivatives, Gross Amounts Offset in Statement of Condition	0	0
Derivatives, Net Amounts of Assets Presented in Statement of Condition	4	1
Derivatives, Net Amount	$ 4	$ 1