INVESTMENTS - Held-to-Maturity Debt Securities (Details) - USD ($) $ in Millions	Jun. 30, 2022		Dec. 31, 2021
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, fixed maturity securities, amortized cost	$ 18,514		$ 22,008
Allowance for Credit Loss	7		8
Total fixed maturity securities, held to maturity, amortized cost	18,507	[1]	22,000
Gross Unrealized Gains	3,025		4,869
Gross Unrealized Losses	0		0
Fair Value	21,532		26,869
Yen-denominated
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, fixed maturity securities, amortized cost	18,514		22,008
Allowance for Credit Loss	7		8
Total fixed maturity securities, held to maturity, amortized cost	18,507		22,000
Gross Unrealized Gains	3,025		4,869
Gross Unrealized Losses	0		0
Fair Value	21,532		26,869
Japan government and agencies | Yen-denominated
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, fixed maturity securities, amortized cost	17,743		21,089
Allowance for Credit Loss	3		3
Total fixed maturity securities, held to maturity, amortized cost	17,740		21,086
Gross Unrealized Gains	2,866		4,613
Gross Unrealized Losses	0		0
Fair Value	20,606		25,699
Municipalities
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, fixed maturity securities, amortized cost	280		335
Fair Value	346		436
Municipalities | Yen-denominated
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, fixed maturity securities, amortized cost	280		335
Allowance for Credit Loss	0		0
Total fixed maturity securities, held to maturity, amortized cost	280		335
Gross Unrealized Gains	66		101
Gross Unrealized Losses	0		0
Fair Value	346		436
Public utilities
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, fixed maturity securities, amortized cost	37		43
Fair Value	43		55
Public utilities | Yen-denominated
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, fixed maturity securities, amortized cost	37		44
Allowance for Credit Loss	0		1
Total fixed maturity securities, held to maturity, amortized cost	37		43
Gross Unrealized Gains	6		12
Gross Unrealized Losses	0		0
Fair Value	43		55
Sovereign and supranational
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, fixed maturity securities, amortized cost	432		514
Fair Value	514		650
Sovereign and supranational | Yen-denominated
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, fixed maturity securities, amortized cost	436		518
Allowance for Credit Loss	4		4
Total fixed maturity securities, held to maturity, amortized cost	432		514
Gross Unrealized Gains	82		136
Gross Unrealized Losses	0		0
Fair Value	514		650
Other corporate
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, fixed maturity securities, amortized cost	18		22
Fair Value	23		29
Other corporate | Yen-denominated
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, fixed maturity securities, amortized cost	18		22
Allowance for Credit Loss	0		0
Total fixed maturity securities, held to maturity, amortized cost	18		22
Gross Unrealized Gains	5		7
Gross Unrealized Losses	0		0
Fair Value	$ 23		$ 29

[1] Net of allowance for credit losses