INVESTMENTS - Held-to-Maturity Debt Securities (Details) - USD ($) $ in Millions	Jun. 30, 2023		Dec. 31, 2022
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 17,441		$ 19,063
Allowance for Credit Loss	5		7
Total fixed maturity securities, held to maturity, amortized cost	17,436	[1]	19,056
Gross Unrealized Gains	2,502		2,154
Gross Unrealized Losses	0		0
Fair   Value	19,938		21,210
Yen-denominated
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	17,441		19,063
Allowance for Credit Loss	5		7
Total fixed maturity securities, held to maturity, amortized cost	17,436		19,056
Gross Unrealized Gains	2,502		2,154
Gross Unrealized Losses	0		0
Fair   Value	19,938		21,210
Japan government and agencies | Yen-denominated
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	16,717		18,269
Allowance for Credit Loss	2		2
Total fixed maturity securities, held to maturity, amortized cost	16,715		18,267
Gross Unrealized Gains	2,387		2,045
Gross Unrealized Losses	0		0
Fair   Value	19,102		20,312
Municipalities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	261		287
Fair   Value	314		335
Municipalities | Yen-denominated
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	261		287
Allowance for Credit Loss	0		0
Total fixed maturity securities, held to maturity, amortized cost	261		287
Gross Unrealized Gains	53		48
Gross Unrealized Losses	0		0
Fair   Value	314		335
Public utilities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	35		37
Fair   Value	39		41
Public utilities | Yen-denominated
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	35		38
Allowance for Credit Loss	0		1
Total fixed maturity securities, held to maturity, amortized cost	35		37
Gross Unrealized Gains	4		4
Gross Unrealized Losses	0		0
Fair   Value	39		41
Sovereign and supranational
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	408		446
Fair   Value	462		500
Sovereign and supranational | Yen-denominated
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	411		450
Allowance for Credit Loss	3		4
Total fixed maturity securities, held to maturity, amortized cost	408		446
Gross Unrealized Gains	54		54
Gross Unrealized Losses	0		0
Fair   Value	462		500
Other corporate
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	17		19
Fair   Value	21		22
Other corporate | Yen-denominated
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	17		19
Allowance for Credit Loss	0		0
Total fixed maturity securities, held to maturity, amortized cost	17		19
Gross Unrealized Gains	4		3
Gross Unrealized Losses	0		0
Fair   Value	$ 21		$ 22

[1] Net of allowance for credit losses