Investments (Schedule Of Average Carrying Value Of Impaired Mortgage Loans On Real Estate) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Information about impaired mortgage loans on real estate
Average carrying value for impaired mortgage loans on real estate	$ 8	$ 5
Interest income recognized on impaired mortgage loans on real estate
Interest income collected on impaired mortgage loans on real estate

Interest income recognized on impaired mortgage loans on real estate.

No definition available.

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Balance Type:	credit
Period Type:	duration