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, 2021	Dec. 31, 2020
Guarantor Obligations [Line Items]
Carrying Value	$ 7	$ 144
Notional / Maximum Exposure to Loss	10,474	28,045
Credit derivatives
Guarantor Obligations [Line Items]
Carrying Value	7	144
Notional / Maximum Exposure to Loss	2,174	19,500
Financial standby letters of credit, net of participations
Guarantor Obligations [Line Items]
Carrying Value	0	0
Notional / Maximum Exposure to Loss	5,339	5,703
Performance standby letters of credit, net of participations
Guarantor Obligations [Line Items]
Carrying Value	0	0
Notional / Maximum Exposure to Loss	2,961	2,842
Affiliated Entity | Credit derivatives
Guarantor Obligations [Line Items]
Notional / Maximum Exposure to Loss	1,591	13,550
Affiliated Entity | Financial and performance standby letters of credit
Guarantor Obligations [Line Items]
Notional / Maximum Exposure to Loss	$ 1,969	$ 1,836