Fair Value Option - Aggregate Differences (Details) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
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	11,700,000,000	11,900,000,000
Contractual lending-related commitments, fair value	56,000,000	10,000,000
Contractual principal outstanding
Loans
Nonaccrual loans	4,012,000,000	4,181,000,000
All other performing loans	57,286,000,000	66,289,000,000
Total loans	61,590,000,000	70,763,000,000
Contractual principal outstanding | Principal-protected debt
Long-term debt
Total long-term debt	35,336,000,000	35,957,000,000
Contractual principal outstanding | Loans reported as trading assets
Loans
Nonaccrual loans	2,988,000,000	3,263,000,000
All other performing loans	8,908,000,000	8,594,000,000
Contractual principal outstanding | Loans
Loans
Nonaccrual loans	1,024,000,000	918,000,000
90 or more days past due and government guaranteed	292,000,000	293,000,000
All other performing loans	48,378,000,000	57,695,000,000
Fair value
Loans
Nonaccrual loans	1,408,000,000	1,343,000,000
All other performing loans	54,724,000,000	65,270,000,000
Total loans	56,416,000,000	66,894,000,000
Long-term debt
Total long-term debt	70,704,000,000	74,934,000,000
Long-term beneficial interests
Total long-term beneficial interests	11,000,000	12,000,000
Fair value | Principal-protected debt
Long-term debt
Total long-term debt	30,307,000,000	33,799,000,000
Fair value | Nonprincipal-protected debt
Long-term debt
Total long-term debt	40,397,000,000	41,135,000,000
Long-term beneficial interests
Total long-term beneficial interests	11,000,000	12,000,000
Fair value | Loans reported as trading assets
Loans
Nonaccrual loans	493,000,000	546,000,000
All other performing loans	7,460,000,000	7,528,000,000
Fair value | Loans
Loans
Nonaccrual loans	915,000,000	797,000,000
90 or more days past due and government guaranteed	284,000,000	281,000,000
All other performing loans	47,264,000,000	57,742,000,000
Fair value over/(under) contractual principal outstanding
Loans
Nonaccrual loans, Fair value over/(under) contractual principal outstanding	(2,604,000,000)	(2,838,000,000)
All other performing loans	(2,562,000,000)	(1,019,000,000)
Total loans	(5,174,000,000)	(3,869,000,000)
Fair value over/(under) contractual principal outstanding | Principal-protected debt
Long-term debt
Long-term debt, Fair value over/(under) contractual principal outstanding	(5,029,000,000)	(2,158,000,000)
Fair value over/(under) contractual principal outstanding | Loans reported as trading assets
Loans
Nonaccrual loans, Fair value over/(under) contractual principal outstanding	(2,495,000,000)	(2,717,000,000)
All other performing loans	(1,448,000,000)	(1,066,000,000)
Fair value over/(under) contractual principal outstanding | Loans
Loans
Nonaccrual loans, Fair value over/(under) contractual principal outstanding	(109,000,000)	(121,000,000)
90 or more days past due and government guaranteed, Fair value over/(under) contractual principal outstanding	(8,000,000)	(12,000,000)
All other performing loans	$ (1,114,000,000)	$ 47,000,000