Netting Arrangements for Certain Financial Instruments and Securities Financing Activities - Information on Company's Accounting Netting Adjustments and Items Not Offset in Consolidated Balance Sheet Assets But Available for Offset in Event of Default (Detail) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Offsetting [Abstract]
Derivative assets Gross Recognized Assets	$ 7,613	$ 7,852
Reverse repurchase agreements Gross Recognized Assets	1,838	107
Securities borrowed Gross Recognized Assets	1,694	1,606
Total Gross Recognized Assets	11,145	9,565
Derivative assets Gross amounts assets offset in consolidated balance sheet	(4,515)	(5,427)
Total Gross amounts assets offset in consolidated balance sheet	(4,515)	(5,427)
Derivative assets Net Amounts Presented in the Consolidated Balance Sheet	3,098	2,425
Reverse repurchase agreements Net Amounts Presented in the Consolidated Balance Sheet	1,838	107
Securities borrowed Net Amounts Presented in the Consolidated Balance Sheet	1,694	1,606
Total Net Amounts Presented in the Consolidated Balance Sheet	6,630	4,138
Derivative assets Gross financial instrument asset amounts not offset in consolidated balance sheet	(785)	(231)
Reverse repurchase agreements Gross financial instrument asset amounts not offset in consolidated balance sheet	(591)	(102)
Total Gross financial instrument asset amounts not offset in consolidated balance sheet	(1,376)	(333)
Derivative assets Gross collateral received amounts not offset in consolidated balance sheet		(80)
Reverse repurchase agreements Gross collateral received amounts not offset in consolidated balance sheet	(1,245)	(5)
Securities borrowed Gross collateral received amounts not offset in consolidated balance sheet	(1,634)	(1,548)
Total Gross collateral received amounts not offset in consolidated balance sheet	(2,879)	(1,633)
Derivative assets Net Amount	2,313	2,114
Reverse repurchase agreements	2
Securities borrowed Net Amount	60	58
Total Net Amount Assets	$ 2,375	$ 2,172