Derivatives and Hedging Activities - Gain (Loss) from Interest Rate Hedges and Related Hedged Items (Detail) - Fair Value Hedging - Accounted for as hedges - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Derivative [Line Items]
Gains/(losses) on Investments	$ (9)	$ 18	$ (5)	$ 15
Gains/(losses) on Borrowings and deposits	(192)	(79)	(456)	(350)
Interest rates
Derivative [Line Items]
Gains/(losses) on Investments	85	427	266	372
Gains/(losses) on Borrowings and deposits	(2,735)	(7,820)	(2,583)	(22,629)
Hedged investments
Derivative [Line Items]
Gains/(losses) on Investments	(94)	(409)	(271)	(357)
Hedged borrowings and deposits
Derivative [Line Items]
Gains/(losses) on Borrowings and deposits	$ 2,543	$ 7,741	$ 2,127	$ 22,279