Investments - Maturity of Fixed Maturity Securities (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Amortized Cost
One year or less	$ 319
After one year through five years	1,104
After five years through ten years	421
After ten years	121
Mortgage-backed/asset-backed securities	60
Cost Basis	$ 2,025	$ 2,029
Amortized Cost, % of Total
One year or less	16.00%
After one year through five years	54.00%
After five years through ten years	21.00%
After ten years	6.00%
Mortgage-backed/asset-backed securities	3.00%
Total	100.00%
Fair Value
One year or less	$ 315
After one year through five years	1,112
After five years through ten years	442
After ten years	125
Mortgage-backed/asset-backed securities	63
Total	$ 2,057	$ 2,090
Fair Value, % of Total
One year or less	15.00%
After one year through five years	55.00%
After five years through ten years	21.00%
After ten years	6.00%
Mortgage-backed/asset-backed securities	3.00%
Total	100.00%