Fair Value Measurements - Fair Value Option (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Fair Value Inputs and Valuation Techniques
Fixed maturities, at fair value using the fair value option	$ 8		$ 11
Changes in fair value of assets using fair value option	0	$ 0
Real Estate Sector [Member]
Fair Value Inputs and Valuation Techniques
Fixed maturities, at fair value using the fair value option	$ 8		$ 11