Fair Value Measurements - Fair Value Option (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair Value Inputs and Valuation Techniques
Fixed maturities, at fair value using the fair value option	$ 11	$ 22
Changes in fair value of assets using fair value option	0
Corporate
Fair Value Inputs and Valuation Techniques
Changes in fair value of assets using fair value option			$ (1)
Equity Securities [Member]
Fair Value Inputs and Valuation Techniques
Changes in fair value of assets using fair value option			$ 1
Real Estate Sector [Member]
Fair Value Inputs and Valuation Techniques
Fixed maturities, at fair value using the fair value option	$ 11	22
Changes in fair value of assets using fair value option		$ (1)