INVESTMENTS - SUCCESSOR COMPANY - Realized Investment Gains (Losses), Net (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Net Investment Income [Line Items]
Net unrealized gains (losses) on investments		$ (312,000)	$ 240,000	$ 2,369,000
Realized		(1,595,000)
Total	$ 481,000	(1,907,000)	7,489,000	(5,261,000)
Retained Business
Net Investment Income [Line Items]
Net unrealized gains (losses) on investments		(517,000)
Realized		(344,000)
Total		(861,000)
Ceded Business
Net Investment Income [Line Items]
Net unrealized gains (losses) on investments		205,000
Realized		(1,251,000)
Total		(1,046,000)
Fixed maturity securities
Net Investment Income [Line Items]
Net unrealized gains (losses) on investments		(285,000)
Realized		(624,000)
Total		(909,000)
Fixed maturity securities | Retained Business
Net Investment Income [Line Items]
Net unrealized gains (losses) on investments		(517,000)
Realized		(123,000)
Total		(640,000)
Fixed maturity securities | Ceded Business
Net Investment Income [Line Items]
Net unrealized gains (losses) on investments		232,000
Realized		(501,000)
Total		(269,000)
Equity securities
Net Investment Income [Line Items]
Net unrealized gains (losses) on investments		(27,000)
Realized		0
Total	(21,000)	(27,000)	1,302,000	(4,000)
Equity securities | Retained Business
Net Investment Income [Line Items]
Net unrealized gains (losses) on investments		0
Realized		0
Total		0
Equity securities | Ceded Business
Net Investment Income [Line Items]
Net unrealized gains (losses) on investments		(27,000)
Realized		0
Total		(27,000)
Secured receivable
Net Investment Income [Line Items]
Net unrealized gains (losses) on investments		0
Realized		(59,000)
Total		(59,000)
Secured receivable | Retained Business
Net Investment Income [Line Items]
Net unrealized gains (losses) on investments		0
Realized		0
Total		0
Secured receivable | Ceded Business
Net Investment Income [Line Items]
Net unrealized gains (losses) on investments		0
Realized		(59,000)
Total		(59,000)
Derivatives
Net Investment Income [Line Items]
Net unrealized gains (losses) on investments		0
Realized		(912,000)
Total	$ 502,000	(912,000)	$ 6,124,000	$ (5,262,000)
Derivatives | Retained Business
Net Investment Income [Line Items]
Net unrealized gains (losses) on investments		0
Realized		(221,000)
Total		(221,000)
Derivatives | Ceded Business
Net Investment Income [Line Items]
Net unrealized gains (losses) on investments		0
Realized		(691,000)
Total		$ (691,000)