Fair Value Option - Aggregate Differences (Details) - USD ($)	Mar. 31, 2023	Dec. 31, 2022
Long-term beneficial interests
Performing loans, ninety days or more past due	$ 0	$ 0
Lending-related commitments, fair value option elected
Long-term beneficial interests
Contractual amount of lending-related commitments	9,400,000,000	7,600,000,000
Contractual lending-related commitments, fair value	12,000,000	24,000,000
Contractual principal outstanding
Loans
Nonaccrual loans	3,371,000,000	3,484,000,000
All other performing loans	49,277,000,000	50,411,000,000
Total loans	52,754,000,000	54,019,000,000
Contractual principal outstanding | Principal-protected debt
Long-term debt
Total long-term debt	44,223,000,000	41,341,000,000
Contractual principal outstanding | Loans reported as trading assets
Loans
Nonaccrual loans	2,437,000,000	2,517,000,000
All other performing loans	10,761,000,000	7,823,000,000
Contractual principal outstanding | Loans
Loans
Nonaccrual loans	934,000,000	967,000,000
90 or more days past due and government guaranteed	106,000,000	124,000,000
All other performing loans	38,516,000,000	42,588,000,000
Fair value
Loans
Nonaccrual loans	1,153,000,000	1,197,000,000
All other performing loans	46,585,000,000	47,270,000,000
Total loans	47,837,000,000	48,582,000,000
Long-term debt
Total long-term debt	76,185,000,000	72,281,000,000
Long-term beneficial interests
Total long-term beneficial interests	1,000,000	5,000,000
Fair value | Principal-protected debt
Long-term debt
Total long-term debt	33,595,000,000	31,105,000,000
Fair value | Nonprincipal-protected debt
Long-term debt
Total long-term debt	42,590,000,000	41,176,000,000
Long-term beneficial interests
Total long-term beneficial interests	1,000,000	5,000,000
Fair value | Loans reported as trading assets
Loans
Nonaccrual loans	365,000,000	368,000,000
All other performing loans	8,926,000,000	6,135,000,000
Fair value | Loans
Loans
Nonaccrual loans	788,000,000	829,000,000
90 or more days past due and government guaranteed	99,000,000	115,000,000
All other performing loans	37,659,000,000	41,135,000,000
Fair value over/(under) contractual principal outstanding
Loans
Nonaccrual loans, Fair value over/(under) contractual principal outstanding	(2,218,000,000)	(2,287,000,000)
All other performing loans	(2,692,000,000)	(3,141,000,000)
Total loans	(4,917,000,000)	(5,437,000,000)
Fair value over/(under) contractual principal outstanding | Principal-protected debt
Long-term debt
Long-term debt, Fair value over/(under) contractual principal outstanding	(10,628,000,000)	(10,236,000,000)
Fair value over/(under) contractual principal outstanding | Loans reported as trading assets
Loans
Nonaccrual loans, Fair value over/(under) contractual principal outstanding	(2,072,000,000)	(2,149,000,000)
All other performing loans	(1,835,000,000)	(1,688,000,000)
Fair value over/(under) contractual principal outstanding | Loans
Loans
Nonaccrual loans, Fair value over/(under) contractual principal outstanding	(146,000,000)	(138,000,000)
90 or more days past due and government guaranteed, Fair value over/(under) contractual principal outstanding	(7,000,000)	(9,000,000)
All other performing loans	$ (857,000,000)	$ (1,453,000,000)