Derivative Financial Instruments - Gains and Losses on Derivative Instruments Held For Other Purpose (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	$ (465)	$ 367
Gain on instruments designated at fair value and related derivatives
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	(482)	360
Gain on instruments designated at fair value and related derivatives | Interest rate contracts
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	(123)	(117)
Gain on instruments designated at fair value and related derivatives | Equity contracts
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	(350)	486
Other income (loss) | Interest rate contracts
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	4	2
Other income (loss) | Credit contracts
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	5	(6)
Other income (loss) | Other Contracts
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	$ (1)	$ 2