FAIR VALUE OF ASSETS AND LIABILITIES - Changes in Level 3 Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Jun. 30, 2021
Insurance Liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	$ (13,661,000)
Total realized and unrealized gains (losses)	2,404,000
Reduction in estimates of ultimate losses	(1,654,000)
Increase in estimates of ultimate losses	1,206,000
Change in fair value (discount rate)	(1,520,000)
Paid losses	98,000
Other	(534,000)
Fair Value, end of period	(11,257,000)	$ (11,257,000)	$ (13,661,000)
Secured receivable
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period		1,622,000
Total realized and unrealized gains (losses)		(50,000)
Purchases		0
Sales		(15,000)
Issuances		0
Settlements		0
Other		(2,000)
Transfers into Level 3		0
Transfers out of Level 3		0
Fair Value, end of period	1,555,000	1,555,000
Unrealized gains (losses) for assets still held		0
Asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period		2,615,000
Total realized and unrealized gains (losses)		(457,000)
Purchases		0
Sales		0
Issuances		0
Settlements		0
Other		0
Transfers into Level 3		0
Transfers out of Level 3		0
Fair Value, end of period	2,158,000	2,158,000
Unrealized gains (losses) for assets still held		0
Reinsurance recoverables
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	1,866,000	344,000	1,881,000	$ 271,000	$ 409,000
Total realized and unrealized gains (losses)		34,000	201,000	27,000	(116,000)
Purchases		0	4,000	4,000	9,000
Sales		0	0	0	0
Issuances		0	0	0	0
Settlements		0	19,000	0	0
Other		0	(239,000)	0	0
Transfers into Level 3		0	0	0	0
Transfers out of Level 3		0	0	0	0
Fair Value, end of period	378,000	378,000	1,866,000	302,000	302,000
Unrealized gains (losses) for assets still held		0	222,000	29,000	(106,000)
Reinsurance recoverables | Realized investment gains (losses), net
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			201,000	26,000	(116,000)
Unrealized gains (losses) for assets still held			222,000	29,000	(106,000)
Reinsurance recoverables | Other income (loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	0	0
Unrealized gains (losses) for assets still held			0	0	0
Reinsurance recoverables | Included in other comprehensive income (loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	0	0
Unrealized gains (losses) for assets still held			0	0	0
Reinsurance recoverables | Net investment income
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	0	0
Net modified coinsurance receivable
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	0	5,000	13,000	12,000	10,000
Total realized and unrealized gains (losses)		210,000	0	0	0
Purchases		0	0	22,000	24,000
Sales		0	0	0	0
Issuances		0	0	0	0
Settlements		0	(13,000)	(12,000)	(12,000)
Other		0	0	0	0
Transfers into Level 3		0	0	1,000	1,000
Transfers out of Level 3		0	0	0	0
Fair Value, end of period	215,000	215,000	0	23,000	23,000
Unrealized gains (losses) for assets still held		0	0	0	0
Net modified coinsurance receivable | Realized investment gains (losses), net
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)				0	0
Unrealized gains (losses) for assets still held				0	0
Net modified coinsurance receivable | Other income (loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)				0	0
Unrealized gains (losses) for assets still held				0	0
Net modified coinsurance receivable | Included in other comprehensive income (loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)				0	0
Unrealized gains (losses) for assets still held				0	0
Net modified coinsurance receivable | Net investment income
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)				0	0
Cash equivalents
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	0		8,000	0	0
Total realized and unrealized gains (losses)			0	0	0
Purchases			0	0	0
Sales			0	0	0
Issuances			0	0	0
Settlements			(8,000)	0	0
Other			0	0	0
Transfers into Level 3			0	0	0
Transfers out of Level 3			0	0	0
Fair Value, end of period			0	0	0
Unrealized gains (losses) for assets still held			0	0	0
Cash equivalents | Realized investment gains (losses), net
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)				0	0
Unrealized gains (losses) for assets still held				0	0
Cash equivalents | Other income (loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)				0	0
Unrealized gains (losses) for assets still held				0	0
Cash equivalents | Included in other comprehensive income (loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)				0	0
Unrealized gains (losses) for assets still held				0	0
Cash equivalents | Net investment income
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)				0	0
Other assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	376,000		400,000	63,000	54,000
Total realized and unrealized gains (losses)			(21,000)	5,000	13,000
Purchases			13,000	4,000	7,000
Sales			0	0	0
Issuances			0	0	0
Settlements			(16,000)	(3,000)	(5,000)
Other			0	0	0
Transfers into Level 3			0	0	0
Transfers out of Level 3			0	0	0
Fair Value, end of period			376,000	69,000	69,000
Unrealized gains (losses) for assets still held			(6,000)	1,000	8,000
Other assets | Realized investment gains (losses), net
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			(21,000)	5,000	13,000
Unrealized gains (losses) for assets still held			(6,000)	1,000	8,000
Other assets | Other income (loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	0	0
Unrealized gains (losses) for assets still held			0	0	0
Other assets | Included in other comprehensive income (loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	0	0
Unrealized gains (losses) for assets still held			0	0	0
Other assets | Net investment income
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	0	0
Future policy benefits
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	(3,393,000)		(4,060,000)	(10,512,000)	(17,314,000)
Total realized and unrealized gains (losses)			715,000	(1,727,000)	5,366,000
Purchases			0	0	0
Sales			0	0	0
Issuances			(48,000)	(291,000)	(582,000)
Settlements			0	0	0
Other			0	0	0
Transfers into Level 3			0	0	0
Transfers out of Level 3			0	0	0
Fair Value, end of period			(3,393,000)	(12,530,000)	(12,530,000)
Unrealized gains (losses) for liabilities still held			686,000	(1,838,000)	4,982,000
Future policy benefits | Realized investment gains (losses), net
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			715,000	(1,728,000)	5,366,000
Unrealized gains (losses) for liabilities still held			686,000	(1,838,000)	4,982,000
Future policy benefits | Other income (loss)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	0	0
Unrealized gains (losses) for liabilities still held			0	0	0
Future policy benefits | Included in other comprehensive income (loss)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	0	0
Unrealized gains (losses) for liabilities still held			0	0	0
Future policy benefits | Net investment income
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	0	0
Policyholders' account balances
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	(1,934,000)		(2,041,000)	(986,000)	(580,000)
Total realized and unrealized gains (losses)			124,000	(240,000)	(508,000)
Purchases			0	0	0
Sales			0	0	0
Issuances			0	(135,000)	(273,000)
Settlements			(17,000)	0	0
Other			0	0	0
Transfers into Level 3			0	0	0
Transfers out of Level 3			0	0	0
Fair Value, end of period			(1,934,000)	(1,361,000)	(1,361,000)
Unrealized gains (losses) for liabilities still held			89,000	(211,000)	(464,000)
Policyholders' account balances | Realized investment gains (losses), net
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			124,000	(240,000)	(508,000)
Unrealized gains (losses) for liabilities still held			89,000	(211,000)	(464,000)
Policyholders' account balances | Other income (loss)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	0	0
Unrealized gains (losses) for liabilities still held			0	0	0
Policyholders' account balances | Included in other comprehensive income (loss)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	0	0
Unrealized gains (losses) for liabilities still held			0	0	0
Policyholders' account balances | Net investment income
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	0	0
Fixed maturities | Fixed maturities, trading
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period				5,000	5,000
Total realized and unrealized gains (losses)				0	0
Purchases				0	0
Sales				0	0
Issuances				0	0
Settlements				0	0
Other				0	0
Transfers into Level 3				0	0
Transfers out of Level 3				0	0
Fair Value, end of period				5,000	5,000
Unrealized gains (losses) for assets still held				0	0
Fixed maturities | Realized investment gains (losses), net | Fixed maturities, available-for-sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	(3,000)	(3,000)
Unrealized gains (losses) for assets still held			0	(3,000)	(3,000)
Fixed maturities | Realized investment gains (losses), net | Fixed maturities, trading
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	0	0
Unrealized gains (losses) for assets still held			0	0	0
Fixed maturities | Other income (loss) | Fixed maturities, available-for-sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	0	0
Unrealized gains (losses) for assets still held			0	0	0
Fixed maturities | Other income (loss) | Fixed maturities, trading
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	0	0
Unrealized gains (losses) for assets still held			0	0	0
Fixed maturities | Included in other comprehensive income (loss) | Fixed maturities, available-for-sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			(12,000)	5,000	4,000
Unrealized gains (losses) for assets still held			(12,000)	3,000	2,000
Fixed maturities | Included in other comprehensive income (loss) | Fixed maturities, trading
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	0	0
Unrealized gains (losses) for assets still held			0	0	0
Fixed maturities | Net investment income | Fixed maturities, available-for-sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	0	0
Fixed maturities | Net investment income | Fixed maturities, trading
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	0	0
Fixed maturities | U.S Treasury securities and obligations of U.S. government authorities and agencies
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	0		0	15,000	15,000
Total realized and unrealized gains (losses)			0	0	0
Purchases			0	0	0
Sales			0	0	0
Issuances			0	0	0
Settlements			0	0	0
Other			0	0	0
Transfers into Level 3			0	0	0
Transfers out of Level 3			0	0	0
Fair Value, end of period			0	15,000	15,000
Unrealized gains (losses) for assets still held			0	0	0
Fixed maturities | Corporate securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	180,000	190,000	190,000	166,000	149,000
Total realized and unrealized gains (losses)		(16,000)	(9,000)	2,000	1,000
Purchases		207,000	5,000	96,000	106,000
Sales		0	(4,000)	0	0
Issuances		0	0	0	0
Settlements		(11,000)	(2,000)	(24,000)	(31,000)
Other		(3,000)	0	0	0
Transfers into Level 3		0	0	0	15,000
Transfers out of Level 3		(53,000)	0	(8,000)	(8,000)
Fair Value, end of period	314,000	314,000	180,000	232,000	232,000
Unrealized gains (losses) for assets still held		(13,000)	(9,000)	1,000	(1,000)
Fixed maturities | Structured securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	47,000	33,000	76,000	17,000	18,000
Total realized and unrealized gains (losses)		0	(4,000)	(1,000)	(1,000)
Purchases		25,000	0	203,000	203,000
Sales		(10,000)	(10,000)	0	0
Issuances		0	0	0	0
Settlements		0	(2,000)	(3,000)	(4,000)
Other		(10,000)	0	0	0
Transfers into Level 3		0	0	0	0
Transfers out of Level 3		(13,000)	(13,000)	0	0
Fair Value, end of period	25,000	25,000	47,000	216,000	216,000
Unrealized gains (losses) for assets still held		$ 0	(4,000)	(1,000)	(1,000)
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period				4,000	4,000
Total realized and unrealized gains (losses)				1,000	1,000
Purchases				0	0
Sales				0	0
Issuances				0	0
Settlements				0	0
Other				0	0
Transfers into Level 3				0	0
Transfers out of Level 3				0	0
Fair Value, end of period				5,000	5,000
Unrealized gains (losses) for assets still held				1,000	1,000
Equity securities | Realized investment gains (losses), net
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	0	0
Unrealized gains (losses) for assets still held			0	0	0
Equity securities | Other income (loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	1,000	1,000
Unrealized gains (losses) for assets still held			0	1,000	1,000
Equity securities | Included in other comprehensive income (loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	0	0
Unrealized gains (losses) for assets still held			0	0	0
Equity securities | Net investment income
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total realized and unrealized gains (losses)			0	$ 0	$ 0
Equity securities | Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	$ 1,000		1,000
Total realized and unrealized gains (losses)			0
Purchases			0
Sales			0
Issuances			0
Settlements			0
Other			0
Transfers into Level 3			0
Transfers out of Level 3			0
Fair Value, end of period			1,000
Unrealized gains (losses) for assets still held			$ 0