Derivative Instruments - Summary of Cumulative Hedging Adjustments and the Carrying Amount of Assets and Liabilities Designated in Fair Value Hedges (Detail) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Available-for-Sale Securities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Carrying Amount of the Hedged Assets	$ 10,541	$ 4,937
Cumulative hedging adjustment included in the carrying amount of the hedged assets	(695)	(552)
Long-term Debt Securities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Carrying amount of the hedged liabilities	16,431	17,190
Cumulative hedging adjustment included in the carrying amount of the hedged liabilities	$ (335)	$ (142)