RELATED-PARTY TRANSACTIONS - Schedule of Premiums and Losses Ceded by Company to Affiliate (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Mt. Logan Re Segregated Accounts
Effects of Reinsurance [Line Items]
Ceded written premiums	$ 71	$ 42
Ceded earned premiums	70	38
Ceded losses and LAE	19	13
Bermuda Re
Effects of Reinsurance [Line Items]
Ceded written premiums	116	106
Ceded earned premiums	116	106
Ceded losses and LAE	$ (2)	$ 4