Derivatives and Hedging Activities - Carrying Amount of Hedged Items Currently Designated in a Hedging Relationship and Related Cumulative Hedging Adjustment (Detail) - Accounted for as hedges - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Investments
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Carrying Value	$ 10,174
Cumulative Hedging Adjustment	(358)
Deposits
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Carrying Value	7,391	$ 14,131
Cumulative Hedging Adjustment	(297)	246
Unsecured short-term borrowings
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Carrying Value	7,553	2,167
Cumulative Hedging Adjustment	(59)	5
Unsecured long-term borrowings
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Carrying Value	150,553	144,934
Cumulative Hedging Adjustment	$ (15,395)	$ 6,169