INVESTMENT OPERATIONS - Schedule of Amortized Cost and Fair Value of Available-for-Sale and Held-to-Maturity Fixed Maturities, by Expected Maturity (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Available-for-sale, Amortized Cost
Amortized Cost	$ 66,022	$ 63,220
Available-for-sale, Fair Value
Total	71,315	70,119
Fixed maturities
Available-for-sale, Amortized Cost
Due in one year or less	1,566
Due after one year through five years	11,358
Due after five years through ten years	14,469
Due after ten years	38,087
Amortized Cost	65,480	62,834
Available-for-sale, Fair Value
Due in one year or less	1,581
Due after one year through five years	11,900
Due after five years through ten years	15,365
Due after ten years	41,927
Total	$ 70,773	$ 69,733