RELATED PARTY TRANSACTIONS - Schedule of Reinsurance Impact on Statement of Operations and Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Jun. 30, 2021
Premiums:
Direct		$ 9.0	$ 6.0	$ 13.0
Assumed		0.0	6.0	16.0
Ceded		(1.0)	(1.0)	(2.0)
Net premiums	$ 3.0	8.0	11.0	27.0
Policy charges and fee income:
Direct		102.0	109.0	216.0
Assumed		0.0	412.0	819.0
Ceded		5.0	7.0	13.0
Policy charges and fee income	(130.0)	(97.0)	(514.0)	(1,022.0)
Asset management and service fees:
Direct		22.0	25.0	48.0
Assumed		0.0	84.0	165.0
Ceded		2.0	2.0	4.0
Net asset management and service fees		20.0	107.0	209.0
Realized investment gains (losses), net:
Direct		312.0	493.0	(1,613.0)
Assumed		0.0	(1,356.0)	4,022.0
Ceded		(169.0)	(26.0)	117.0
Investment gains (losses), net	(1,298.0)	481.0	(837.0)	2,292.0
Policyholders' benefits (including change in reserves):
Direct		31.0	7.0	24.0
Assumed		0.0	(10.0)	3.0
Ceded		(5.0)	(1.0)	(1.0)
Policyholders’ benefits	0.0	26.0	(4.0)	26.0
Interest credited to policyholders’ account balances:
Direct		91.0	15.0	96.0
Assumed		0.0	6.0	77.0
Ceded		(6.0)	0.0	(4.0)
Interest credited to policyholders’ account balances	$ 0.0	85.0	21.0	169.0
Net interest credited to policyholders’ account balances		(41.0)	175.0	514.0
Unaffiliated
Policy charges and fee income:
Ceded		0.0	(0.3)	0.4
Interest credited to policyholders’ account balances:
Unaffiliated activity		$ 0.0	$ (0.1)	$ (0.4)