Guaranteed Benefit Features (Summary Of Guaranteed Death Benefit Liabilities) (Details) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017
Guaranteed Benefit Features [Abstract]
Balance as of beginning-of-year	$ 100	$ 110
Changes in reserves	18	(2)
Benefits paid	(7)	(11)
Balance as of end-of-period	$ 111	$ 97

Guaranteed Benefit Features [Abstract]

No definition available.

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- Definition

Liabilities for Guarantees on Long-Duration Contracts, Increase (decrease) in reserves

+ References

No definition available.

+ Details

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- Definition

Amount of expected guaranteed benefits in excess of the projected account balances for minimum guaranteed benefit contracts, as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 20
-Section 55
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=6588021&loc=d3e7104-158389

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 80
-Section 50
-Paragraph 1
-Subparagraph (d)(3)
-URI http://asc.fasb.org/extlink&oid=6484115&loc=d3e19393-158473

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- Definition

Amount of cash outflow to policyholders and contract holders for guaranteed minimum benefit payments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 20
-Section 55
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=6588021&loc=d3e7104-158389

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 80
-Section 50
-Paragraph 1
-Subparagraph (d)(4)
-URI http://asc.fasb.org/extlink&oid=6484115&loc=d3e19393-158473

+ Details

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