INVESTMENTS - Investment Exposures Individually Exceeded 10% of Shareholders' Equity (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022
Investments [Abstract]
Credit Rating	[1]	A+	A+
Amortized Cost	[1]	$ 39,151	$ 42,618
Fair Value	[1]	$ 40,222	$ 44,178
Investment, Type [Extensible Enumeration]		Japan National Government [Member]	Japan National Government [Member]

[1] Japan Government Bonds (JGBs) or JGB-backed securities