INVESTMENTS - Net Investment Income (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net Investment Income [Line Items]
Investment income	$ 3,347	$ 3,442	$ 2,549
Investment expenses	(139)	(144)	(71)
Net investment income (loss)	3,208	3,298	2,478
Fixed maturities
Net Investment Income [Line Items]
Investment income	2,193	1,902	1,540
Mortgage loans on real estate
Net Investment Income [Line Items]
Investment income	516	540	494
Other equity investments
Net Investment Income [Line Items]
Investment income	79	72	117
Policy loans
Net Investment Income [Line Items]
Investment income	198	198	201
Trading securities
Net Investment Income [Line Items]
Investment income	312	712	128
Other investment income
Net Investment Income [Line Items]
Investment income	$ 49	$ 18	$ 69

Represents the total of interest and dividend income, including any amortization and accretion (as applicable) of discounts and premiums, earned from (1) loans and leases whether held-for-sale or held-in-portfolio; (2) investment securities; (3) federal funds sold; (4) securities purchased under agreements to resell; (5) investments in banker's acceptances, commercial paper, or certificates of deposit; (6) dividend income; or (7) other investments not otherwise specified herein.

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