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, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Allowance for Losses
Balance as of beginning-of-period	$ 3	$ 2	$ 3	$ 2
Additions
Charge-offs, net of recoveries	(1)		(1)
Balance as of end-of-period	$ 2	$ 2	$ 2	$ 2