Investments (Average Carrying Value On The Impaired Mortgage Loans On Real Estate) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015
Information about impaired mortgage loans on real estate
Average carrying value for impaired loans on real estate	$ 6	$ 23
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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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration