Investments (Changes In The Valuation Allowance Of Impaired Mortgage Loans On Real Estate (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Allowance for Losses
Balance as of beginning-of-period	$ 2	$ 2	$ 2	$ 2
Additions
Charge-offs, net of recoveries
Balance as of end-of-period	$ 2	$ 2	$ 2	$ 2