Investments - Debt Maturities (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Embedded derivatives - fixed maturities
Available-for-sale Securities Including Securities Pledged [Line Items]
One year or less, Amortized Cost	$ 824
One year or less, Fair Value	832
After one year through five years, Amortized Cost	3,324
After one year through five years, Fair Value	3,501
After five years through ten years, Amortized Cost	5,528
After five years through ten years, Fair Value	6,080
After ten years, Amortized Cost	7,818
After ten years, Fair Value	9,511
Amortized Cost	25,957	$ 25,336
Fixed maturities, including securities pledged	$ 28,592	$ 27,460
Mortgage-backed securities
Available-for-sale Securities Including Securities Pledged [Line Items]
Percent Collateralized Mortgage Backed Securities including Interest-Only Strip or Principal-Only Strip	48.30%	48.40%
Without single maturity date, Amortized Cost	$ 6,970
Without single maturity date, Fair Value	7,198
Other asset-backed securities
Available-for-sale Securities Including Securities Pledged [Line Items]
Without single maturity date, Amortized Cost	1,493
Without single maturity date, Fair Value	1,470
Amortized Cost	1,493	$ 1,472
Fixed maturities, including securities pledged	$ 1,470	$ 1,474