INVESTMENTS - Commercial mortgage and other loans (Details) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
SEC Schedule, 12-29, Real Estate Companies, Investment in Movement in Mortgage Loans on Real Estate [Roll Forward]
Allowance, beginning of period	$ 5	$ 7	$ 7
Release of allowance for expected losses	(1)	(2)	(2)
Allowance, end of period	4	5	5
Total commercial mortgage and agricultural property loans				$ 1,508
Total commercial mortgage and agricultural property loans, percent				1.000
Total commercial mortgage loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Movement in Mortgage Loans on Real Estate [Roll Forward]
Allowance, beginning of period	5	7	7
Release of allowance for expected losses	(1)	(2)	(2)
Allowance, end of period	4	5	5
Total commercial mortgage and agricultural property loans				$ 1,457
Total commercial mortgage and agricultural property loans, percent				0.967
Agricultural Property Loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Movement in Mortgage Loans on Real Estate [Roll Forward]
Allowance, beginning of period	0	0	0
Release of allowance for expected losses	0	0	0
Allowance, end of period	$ 0	$ 0	$ 0
Total commercial mortgage and agricultural property loans				$ 51
Total commercial mortgage and agricultural property loans, percent				0.033
Apartments/Multi-Family
SEC Schedule, 12-29, Real Estate Companies, Investment in Movement in Mortgage Loans on Real Estate [Roll Forward]
Total commercial mortgage and agricultural property loans				$ 385
Total commercial mortgage and agricultural property loans, percent				0.255