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 Liabilities But Available for Offset in Event of Default (Detail) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Offsetting [Abstract]
Derivative liabilities Gross recognized liabilities	$ 11,698	$ 10,506
Repurchase agreements Gross recognized liabilities	2,666	1,432
Securities loaned Gross recognized liabilities	212	120
Total Gross recognized liabilities	14,576	12,058
Derivative liabilities Gross amounts liabilities offset in consolidated balance sheet	(4,307)	(4,551)
Total Gross amounts liabilities offset in consolidated balance sheet	(4,307)	(4,551)
Derivative liabilities Net amounts liabilities presented in consolidated balance sheet	7,391	5,955
Repurchase agreements Net amounts liabilities presented in consolidated balance sheet	2,666	1,432
Securities loaned Net amounts liabilities presented in consolidated balance sheet	212	120
Total Net amounts liabilities presented in consolidated balance sheet	10,269	7,507
Derivative liabilities Gross financial instrument liability amounts not offset in consolidated balance sheet	(785)	(231)
Repurchase agreements Gross financial instrument liability amounts not offset in consolidated balance sheet	(591)	(102)
Total Gross financial instrument liability amounts not offset in consolidated balance sheet	(1,376)	(333)
Repurchase agreements Gross collateral pledged amounts not offset in consolidated balance sheet	(2,071)	(1,325)
Securities loaned Gross collateral pledged amounts not offset in consolidated balance sheet	(208)	(118)
Total Gross collateral pledged amounts not offset in consolidated balance sheet	(2,279)	(1,443)
Derivative liabilities Net Amount	6,606	5,724
Repurchase agreements Net Amount	4	5
Securities loaned Net Amount	4	2
Total Net Amount Liabilities	$ 6,614	$ 5,731