Collateralized Agreements and Financings - Schedule of Gross Carrying Value of Repurchase Agreements and Securities Loaned by Class of Collateral Pledged (Detail) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Offsetting Liabilities [Line Items]
Repurchase agreements	$ 509,497	$ 502,148
Securities loaned	70,958	71,581
Money market instruments
Offsetting Liabilities [Line Items]
Repurchase agreements	1,653	395
Securities loaned	0	0
U.S. government and agency obligations
Offsetting Liabilities [Line Items]
Repurchase agreements	286,706	319,406
Securities loaned	281	0
Non-U.S. government obligations
Offsetting Liabilities [Line Items]
Repurchase agreements	180,519	141,625
Securities loaned	132	1,416
Securities backed by commercial real estate
Offsetting Liabilities [Line Items]
Repurchase agreements	212	247
Securities loaned	8	0
Securities backed by residential real estate
Offsetting Liabilities [Line Items]
Repurchase agreements	2,572	2,219
Securities loaned	17	0
Corporate debt securities
Offsetting Liabilities [Line Items]
Repurchase agreements	16,762	13,281
Securities loaned	428	186
State and municipal obligations
Offsetting Liabilities [Line Items]
Repurchase agreements	489	370
Securities loaned	0	0
Other debt obligations
Offsetting Liabilities [Line Items]
Repurchase agreements	108	89
Securities loaned	0	0
Equity securities
Offsetting Liabilities [Line Items]
Repurchase agreements	20,476	24,516
Securities loaned	$ 70,092	$ 69,979