Investments - Schedule of Carrying Amount and Fair Value of Available for Sale Securities (Details) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Fixed maturity securities available for sale:
Carrying Value	$ 2,057,000,000	$ 2,090,000,000
Cost Basis	2,025,000,000	2,029,000,000
Unrealized Gains	60,000,000	67,000,000
Unrealized Losses	(17,000,000)	(6,000,000)
Allowance for Credit Loss	(11,000,000)	0
U.S. government and agencies
Fixed maturity securities available for sale:
Carrying Value	278,000,000	288,000,000
Cost Basis	265,000,000	282,000,000
Unrealized Gains	13,000,000	7,000,000
Unrealized Losses	0	(1,000,000)
Allowance for Credit Loss	0
State and political subdivisions
Fixed maturity securities available for sale:
Carrying Value	92,000,000	93,000,000
Cost Basis	90,000,000	90,000,000
Unrealized Gains	2,000,000	3,000,000
Unrealized Losses	0	0
Allowance for Credit Loss	0
Corporate debt securities
Fixed maturity securities available for sale:
Carrying Value	1,567,000,000	1,587,000,000
Cost Basis	1,547,000,000	1,536,000,000
Unrealized Gains	42,000,000	54,000,000
Unrealized Losses	(11,000,000)	(3,000,000)
Allowance for Credit Loss	(11,000,000)
Mortgage-backed/asset-backed securities
Fixed maturity securities available for sale:
Carrying Value	63,000,000	62,000,000
Cost Basis	60,000,000	60,000,000
Unrealized Gains	3,000,000	2,000,000
Unrealized Losses	0	0
Allowance for Credit Loss	0
Foreign government bonds
Fixed maturity securities available for sale:
Carrying Value	57,000,000	60,000,000
Cost Basis	63,000,000	61,000,000
Unrealized Gains	0	1,000,000
Unrealized Losses	(6,000,000)	$ (2,000,000)
Allowance for Credit Loss	$ 0