Offsetting Arrangements - Assets With Offsetting Arrangements (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Offsetting Assets [Line Items]
Derivatives, Gross Amounts of Recognized Assets	$ 15,148	$ 16,399
Derivatives, Gross Amounts Offset in Statement of Condition	(10,395)	(11,210)
Derivatives, Net Amounts of Assets Presented in Statement of Condition	4,753	5,189
Derivatives, Net Amount	4,068	4,969
Derivatives, Cash collateral and securities netting, cash offset	(2,310)	(987)
Derivatives, Cash collateral and securities netting, Cash and Securities Received	(685)	(220)
Derivatives, Cash collateral and securities netting, Net Amount	(2,995)	(1,207)
Resale agreements and securities borrowing, Gross Amounts of Recognized Assets	179,989	116,143
Resale agreements and securities borrowing, Gross Amounts Offset in Statement of Condition	159,978	91,889
Resale agreements and securities borrowing, Net Amounts of Assets Presented in Statement of Condition	20,011	24,254
Resale agreements and securities borrowing, Cash and Securities Received	(19,572)	(22,872)
Resale agreements and securities borrowing, Net Amount	439	1,382
Total derivatives and other financial instruments, Gross Amounts of Recognized Assets	195,137	132,542
Total derivatives and other financial instruments, Gross Amounts Offset in Statement of Condition	(170,373)	(103,099)
Total derivatives and other financial instruments, Net Amounts of Assets Presented in Statement of Condition	24,764	29,443
Total derivatives and other financial instruments, Cash and Securities Received	(20,257)	(23,092)
Total derivatives and other financial instruments, Net Amount	4,507	6,351
Securities purchased under resale agreements	1,487	4,679
Cash collateral provided for securities borrowing	18,520	19,580
Foreign exchange contracts
Offsetting Assets [Line Items]
Derivatives, Gross Amounts of Recognized Assets	15,140	16,386
Derivatives, Gross Amounts Offset in Statement of Condition	(8,081)	(10,223)
Derivatives, Net Amounts of Assets Presented in Statement of Condition	7,059	6,163
Derivatives, Net Amount	7,059	6,163
Interest rate contracts
Offsetting Assets [Line Items]
Derivatives, Gross Amounts of Recognized Assets	8	13
Derivatives, Gross Amounts Offset in Statement of Condition	(4)	0
Derivatives, Net Amounts of Assets Presented in Statement of Condition	4	13
Derivatives, Net Amount	$ 4	$ 13