Investments (Schedule Of Average Carrying Value 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
Information about impaired mortgage loans on real estate
Average carrying value for impaired mortgage loans on real estate	$ 7	$ 5	$ 7	$ 5
Interest income recognized on impaired mortgage loans on real estate
Interest income collected on impaired mortgage loans on real estate