Closed Block (Information Regarding Policyholder Dividend Obligation) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Movement in Closed Block Dividend Obligation [Roll Forward]
Balance, January 1	$ 4,509	$ 6,612
Impact from earnings allocable to policyholder dividend obligation	(48)	137
Change in net unrealized investment gains (losses) allocated to policyholder dividend obligation	197	(2,240)
Balance, December 31	$ 4,658	$ 4,509

Amount of increase (decrease) in the closed block dividend obligation from the unrealized gain (loss) on investments allocated to the closed block.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 805
-Section 35
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=6487164&loc=d3e30481-158566

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 805
-Section 55
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=34726331&loc=d3e31071-158570

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 805
-Section 50
-Paragraph 3
-Subparagraph (b)(10)
-URI http://asc.fasb.org/extlink&oid=6487222&loc=d3e30806-158569

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- Definition

Amount of increase (decrease) in the closed block dividend obligation from the effect on dividends to policyholders on the net results of operations for the period of the closed block.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 805
-Section 50
-Paragraph 3
-Subparagraph (b)(10)
-URI http://asc.fasb.org/extlink&oid=6487222&loc=d3e30806-158569

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 805
-Section 55
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=34726331&loc=d3e31071-158570

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- Definition

The liability as of the balance sheet date for the excess of the cumulative actual closed block earnings over the cumulative expected (actuarially determined) closed block earnings (each) for the period from the actuarial calculation date to the date of measurement. The excess will result in future dividends to closed block policyholders, unless offset by less favorable than expected future performance of the closed block. The policyholder dividend obligation, which may not have a negative balance, recognizes that a portion of earnings in certain cases will not inure to the stockholders of the insurance entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 805
-Section 55
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=34726331&loc=d3e31071-158570

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 805
-Section 50
-Paragraph 3
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=6487222&loc=d3e30806-158569

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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