Guarantee Arrangements, Pledged Assets and Repurchase Agreements - Summary of Credit Ratings of Credit Risk Related Guarantees (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	$ 10,726	$ 10,649
Total, Notional/Maximum Exposure to Loss	12,097	13,213
Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	$ 2,992	$ 3,949
Single name credit default swaps | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Average Life (in years)	1 year 4 months 24 days
Credit derivatives, Notional/Maximum Exposure to Loss	$ 1,359
Index credit derivatives | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Average Life (in years)	6 years 6 months
Credit derivatives, Notional/Maximum Exposure to Loss	$ 1,633
Standby Letters of Credit
Credit Derivatives [Line Items]
Average Life (in years)	10 months 24 days
Standby letters of credit, Notional/Maximum Exposure to Loss	$ 9,105
Investment Grade
Credit Derivatives [Line Items]
Total, Notional/Maximum Exposure to Loss	8,629
Investment Grade | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	1,978
Investment Grade | Single name credit default swaps | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	903
Investment Grade | Index credit derivatives | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	1,075
Investment Grade | Standby Letters of Credit
Credit Derivatives [Line Items]
Standby letters of credit, Notional/Maximum Exposure to Loss	6,651
Non-Investment Grade
Credit Derivatives [Line Items]
Total, Notional/Maximum Exposure to Loss	3,468
Non-Investment Grade | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	1,014
Non-Investment Grade | Single name credit default swaps | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	456
Non-Investment Grade | Index credit derivatives | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	558
Non-Investment Grade | Standby Letters of Credit
Credit Derivatives [Line Items]
Standby letters of credit, Notional/Maximum Exposure to Loss	$ 2,454