FAIR VALUE OF ASSETS AND LIABILITIES - Schedule of paid (Details) - Insurance liabilities - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2023
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	$ 13,611	$ 5,546
Reduction in estimates of ultimate losses	(8,095)	(2,329)
Increase in estimates of ultimate losses	1,936	1,307
Change in fair value (discount rate)	(2,266)	52
Paid losses	315	432
Other	45	(5)
Fair Value, end of period	5,546	5,003
Retained Business
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	3,362	2,941
Reduction in estimates of ultimate losses	(632)	(1,347)
Increase in estimates of ultimate losses	1,759	817
Change in fair value (discount rate)	(1,863)	45
Paid losses	282	384
Other	33	(5)
Fair Value, end of period	2,941	2,835
Ceded Business
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	10,249	2,605
Reduction in estimates of ultimate losses	(7,463)	(982)
Increase in estimates of ultimate losses	177	490
Change in fair value (discount rate)	(403)	7
Paid losses	33	48
Other	12	0
Fair Value, end of period	$ 2,605	$ 2,168

FORTITUDE LIFE INSURANCE & ANNUITY CO 10-K