Derivative Financial Instruments - Gains and Losses on Derivative Instruments Held For Other Purpose (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	$ (181)	$ 70
Gain (loss) on instruments designated at fair value and related derivatives
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	(169)	98
Gain (loss) on instruments designated at fair value and related derivatives \| Interest rate contracts
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	32	(54)
Gain (loss) on instruments designated at fair value and related derivatives \| Equity contracts - bilateral OTC(2)
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	(200)	151
Other income (loss) \| Equity contracts - bilateral OTC(2)
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	(3)	0
Other income (loss) \| Credit contracts
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	(3)	(25)
Other income (loss) \| Other Contracts
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	$ (7)	$ (2)