Fair Value Measurements - Fair Value Option (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Fair Value Inputs and Valuation Techniques
Fixed maturities, at fair value using the fair value option	$ 0		$ 0		$ 11
Changes in fair value of assets using fair value option	0	$ 0	0	$ 0
Real Estate Sector [Member]
Fair Value Inputs and Valuation Techniques
Fixed maturities, at fair value using the fair value option	$ 0		$ 0		$ 11