INVESTMENTS - Investment Exposures Individually Exceeded 10% of Shareholders' Equity (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
		Mar. 31, 2025	Dec. 31, 2024
Summary of Investment Holdings [Line Items]
Credit Rating	[1]	A+	A+
Amortized Cost	[1]	$ 35,251	$ 33,822
Fair Value	[1]	$ 33,082	$ 32,844
Investment, Type [Extensible Enumeration]		Japan National Government	Japan National Government

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