Guarantee Arrangements, Pledged Assets and Repurchase Agreements - Summary of Credit Ratings of Credit Risk Related Guarantees (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	$ 7,378	$ 2,675
Total, Notional/Maximum Exposure to Loss	12,274	10,474
Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	$ 3,402	$ 2,174
Single name credit default swaps | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Average Life (in years)	1 year 7 months 6 days
Credit derivatives, Notional/Maximum Exposure to Loss	$ 1,489
Index credit derivatives | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Average Life (in years)	6 years 8 months 12 days
Credit derivatives, Notional/Maximum Exposure to Loss	$ 1,913
Standby Letters of Credit
Credit Derivatives [Line Items]
Average Life (in years)	1 year
Standby letters of credit, Notional/Maximum Exposure to Loss	$ 8,872
Investment Grade
Credit Derivatives [Line Items]
Total, Notional/Maximum Exposure to Loss	8,111
Investment Grade | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	1,493
Investment Grade | Single name credit default swaps | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	920
Investment Grade | Index credit derivatives | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	573
Investment Grade | Standby Letters of Credit
Credit Derivatives [Line Items]
Standby letters of credit, Notional/Maximum Exposure to Loss	6,618
Non-Investment Grade
Credit Derivatives [Line Items]
Total, Notional/Maximum Exposure to Loss	4,163
Non-Investment Grade | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	1,909
Non-Investment Grade | Single name credit default swaps | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	569
Non-Investment Grade | Index credit derivatives | Sell-protection Credit Derivatives
Credit Derivatives [Line Items]
Credit derivatives, Notional/Maximum Exposure to Loss	1,340
Non-Investment Grade | Standby Letters of Credit
Credit Derivatives [Line Items]
Standby letters of credit, Notional/Maximum Exposure to Loss	$ 2,254