Securities Financing Activities - Types of Financial Assets Pledged and Remaining Maturity (Details) - USD ($) $ in Millions	Sep. 30, 2026	Dec. 31, 2025
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements	$ 1,018,059	$ 715,251
Securities loaned and other	103,696	86,829
Overnight and continuous
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements	580,580	406,605
Securities loaned and other	83,610	78,233
Up to 30 days
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements	262,442	168,256
Securities loaned and other	66	1,316
30 – 90 days
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements	41,270	18,169
Securities loaned and other	6,065	976
Greater than 90 days
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements	133,767	122,221
Securities loaned and other	13,955	6,304
Mortgage-backed securities, U.S. GSEs and government agencies
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements	135,773	124,776
Securities loaned and other	0	0
Mortgage-backed securities, Residential - nonagency
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements	4,019	1,685
Securities loaned and other	0	0
Mortgage-backed securities, Commercial - nonagency
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements	1,723	2,285
Securities loaned and other	0	0
U.S. Treasury, GSEs and government agencies
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements	518,332	346,938
Securities loaned and other	6,579	703
Obligations of U.S. states and municipalities
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements	3,377	1,624
Securities loaned and other	0	0
Non-U.S. government debt
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements	210,036	122,346
Securities loaned and other	4,056	1,415
Corporate debt securities
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements	73,711	66,100
Securities loaned and other	5,931	3,433
Asset-backed securities
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements	5,357	6,545
Securities loaned and other	0	0
Equity securities
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements	65,731	42,952
Securities loaned and other	$ 87,130	$ 81,278