Securities Financing Activities, Gross Obligations by Underlying Collateral Type (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	$ 371,045	$ 322,482
Securities lending arrangements	8,728	7,558
Total repurchases and securities lending	379,773	330,040
Securities of U.S. Treasury and federal agencies [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	229,028	176,386
Federal agency mortgage-backed securities [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	114,105	118,503
Non-agency mortgage-backed securities [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	3,435	3,266
Corporate debt securities [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	14,854	13,567
Securities lending arrangements	2,845	1,735
Asset-backed securities [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	4,148	4,705
Equity securities [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	2,367	2,809
Securities lending arrangements	5,667	5,700
Other [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	3,108	3,246
Securities lending arrangements	$ 216	$ 123