INVESTMENTS - Alternative Investment Funds (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Investments in Alternative Investment Funds
Alternative investment funds, unfunded commitments	$ 61	$ 61
Private equity funds
Investments in Alternative Investment Funds
Alternative investment funds, unfunded commitments	60	60
Real estate funds
Investments in Alternative Investment Funds
Alternative investment funds, unfunded commitments	1	1
Mutual/collective investment funds
Investments in Alternative Investment Funds
Alternative investment funds, unfunded commitments	0	0
Fair value
Investments in Alternative Investment Funds
Non-marketable equity securities measured using the measurement alternative	158	145
Fair value | Private equity funds
Investments in Alternative Investment Funds
Non-marketable equity securities measured using the measurement alternative	132	123
Fair value | Real estate funds
Investments in Alternative Investment Funds
Non-marketable equity securities measured using the measurement alternative	2	2
Fair value | Mutual/collective investment funds
Investments in Alternative Investment Funds
Non-marketable equity securities measured using the measurement alternative	$ 24	$ 20