Guarantee Arrangements, Pledged Assets and Repurchase Agreements - Summary of Credit Ratings of Credit Risk Related Guarantees (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	$ 6,624	$ 10,649
Total, Notional/Maximum Exposure to Loss	11,849	13,213
Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	$ 2,783	$ 3,949
Single name credit default swaps | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Average Life (in years)	1 year 2 months 12 days
Credit derivatives, Notional/Maximum Exposure to Loss	$ 1,673
Index credit derivatives | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Average Life (in years)	7 years 10 months 24 days
Credit derivatives, Notional/Maximum Exposure to Loss	$ 1,110
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	$ 9,066
Investment Grade
Credit Derivatives [Line Items]
Total, Notional/Maximum Exposure to Loss	7,999
Investment Grade | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	1,824
Investment Grade | Single name credit default swaps | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	1,099
Investment Grade | Index credit derivatives | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	725
Investment Grade | Standby Letters of Credit
Credit Derivatives [Line Items]
Standby letters of credit, Notional/Maximum Exposure to Loss	6,175
Non-Investment Grade
Credit Derivatives [Line Items]
Total, Notional/Maximum Exposure to Loss	3,850
Non-Investment Grade | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	959
Non-Investment Grade | Single name credit default swaps | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	574
Non-Investment Grade | Index credit derivatives | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	385
Non-Investment Grade | Standby Letters of Credit
Credit Derivatives [Line Items]
Standby letters of credit, Notional/Maximum Exposure to Loss	$ 2,891