Investments (Average Carrying Value On The Impaired Mortgage Loans On Real Estate) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Information about impaired mortgage loans on real estate
Average carrying value for impaired loans on real estate	$ 5	$ 6

Average carrying value for impaired loans on real estate.

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration