Commitments, Contingencies and Guarantees - Commitments (Detail) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Commitment Liabilities [Line Items]
Total commitments	$ 429,050	$ 381,539
Remainder of Fiscal Year	236,980
2024-2025	65,193
2026-2027	84,061
2028-Thereafter	42,816
Total lending
Commitment Liabilities [Line Items]
Total commitments	239,697	227,138
Remainder of Fiscal Year	74,468
2024-2025	48,174
2026-2027	79,315
2028-Thereafter	37,740
Investment-grade
Commitment Liabilities [Line Items]
Total commitments	103,435	100,438
Remainder of Fiscal Year	3,906
2024-2025	26,191
2026-2027	50,308
2028-Thereafter	23,030
Increase (decrease) in lending commitments		2,780
Non-investment-grade
Commitment Liabilities [Line Items]
Total commitments	55,873	53,486
Remainder of Fiscal Year	1,227
2024-2025	14,158
2026-2027	26,034
2028-Thereafter	14,454
Increase (decrease) in lending commitments		(2,780)
Warehouse financing
Commitment Liabilities [Line Items]
Total commitments	9,312	9,116
Remainder of Fiscal Year	220
2024-2025	5,863
2026-2027	2,973
2028-Thereafter	256
Consumer
Commitment Liabilities [Line Items]
Total commitments	71,077	64,098
Remainder of Fiscal Year	69,115
2024-2025	1,962
2026-2027	0
2028-Thereafter	0
Risk participations
Commitment Liabilities [Line Items]
Total commitments	8,651	9,173
Remainder of Fiscal Year	1,056
2024-2025	2,842
2026-2027	3,731
2028-Thereafter	1,022
Collateralized agreement
Commitment Liabilities [Line Items]
Total commitments	107,459	105,301
Remainder of Fiscal Year	99,463
2024-2025	7,230
2026-2027	0
2028-Thereafter	766
Collateralized financing
Commitment Liabilities [Line Items]
Total commitments	44,667	22,532
Remainder of Fiscal Year	40,027
2024-2025	4,586
2026-2027	0
2028-Thereafter	54
Investment
Commitment Liabilities [Line Items]
Total commitments	20,745	7,705
Remainder of Fiscal Year	15,246
2024-2025	1,474
2026-2027	1,015
2028-Thereafter	3,010
Other
Commitment Liabilities [Line Items]
Total commitments	7,831	$ 9,690
Remainder of Fiscal Year	6,720
2024-2025	887
2026-2027	0
2028-Thereafter	$ 224