Guarantee Arrangements, Pledged Assets and Repurchase Agreements - Carrying Value and Contractual Amounts of our Sell Protection Credit Derivatives and Major Off-Balance Sheet Guarantee Arrangements (Detail) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Guarantor Obligations [Line Items]
Total, Carrying Value	$ 191	$ 54
Credit derivatives, Notional/Maximum Exposure to Loss	5,521	10,726
Total, Notional/Maximum Exposure to Loss	15,428	12,097
Sell-protection Credit Derivatives
Guarantor Obligations [Line Items]
Credit derivatives, Carrying Value	191	54
Credit derivatives, Notional/Maximum Exposure to Loss	6,827	2,992
Financial standby letters of credit, net of participations
Guarantor Obligations [Line Items]
Standby letters of credit, Carrying Value	0	0
Standby letters of credit, Notional/Maximum Exposure to Loss	5,337	5,785
Performance standby letters of credit, net of participations
Guarantor Obligations [Line Items]
Standby letters of credit, Carrying Value	0	0
Standby letters of credit, Notional/Maximum Exposure to Loss	3,264	3,320
Affiliated Entity | Sell-protection Credit Derivatives
Guarantor Obligations [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	2,797	1,483
Affiliated Entity | Financial and performance standby letters of credit
Guarantor Obligations [Line Items]
Standby letters of credit, Notional/Maximum Exposure to Loss	$ 1,590	$ 2,080