Investments and Derivative Instruments Level 4 Derivative Collateral Arrangements (Details) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Derivative Collateral Arrangements [Line Items]
Security Owned and Pledged as Collateral, Fair Value	$ 120,000,000	$ 347,000,000
Derivative Asset, Collateral, Obligation to Return Cash, Offset	327,000,000	180,000,000
Derivative, Collateral, Obligation to Return Securities	109,000,000	243,000,000
Fair Value of Securities Received as Collateral that Can be Resold or Repledged	97,000,000	191,000,000
Securities Received as Collateral, Amount Repledged and Sold	0	39,000,000
Fixed Maturities [Member]
Derivative Collateral Arrangements [Line Items]
Security Owned and Pledged as Collateral, Fair Value	$ 1,100,000,000	$ 1,300,000,000
J.P. Morgan Chase [Member] \| Corporate Debt Securities [Member]
Derivative Collateral Arrangements [Line Items]
Largest Exposure by Issuer, Percent of Invested Assets	1.00%
GOLDMAN SACH MTF [Member] \| Corporate Debt Securities [Member]
Derivative Collateral Arrangements [Line Items]
Largest Exposure by Issuer, Percent of Invested Assets	1.00%	4.00%
ILLINOIS \| US States and Political Subdivisions Debt Securities [Member]
Derivative Collateral Arrangements [Line Items]
Largest Exposure by Issuer, Percent of Invested Assets	1.00%	4.00%

The percent of invested assets by the Company's largest exposure by issuer.

No definition available.

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- Definition

Amount of obligation to return cash collateral under master netting arrangements offset against derivative assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=34720828&loc=SL20225862-175312

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- Definition

Amount of obligation to return securities collateral under master netting arrangements that have not been offset against derivative assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 13

-URI http://asc.fasb.org/extlink&oid=36459792&loc=SL20226016-175313

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (d)(2)

-URI http://asc.fasb.org/extlink&oid=34720828&loc=SL20225862-175312

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- Definition

Fair value of collateral permitted, by contact or custom, to be sold or re-pledged.

+ References

+ Details

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- Definition

The fair value of collateral received that has been sold or re-pledged and is owed to the debtor (transferor) upon settlement of the related contractual obligation under which it was received.

+ References

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- Definition

Fair value of financial instrument held by the entity for its own account (proprietary securities) for trading or investment purposes that are carried at fair value and pledged to counterparties as collateral for financing transactions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 30

-Section 50

-Paragraph 1A

-Subparagraph (b)(1)(i)

-URI http://asc.fasb.org/extlink&oid=34720971&loc=SL6224234-111729

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 30

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6467456&loc=d3e113888-111728

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