Investments and Derivative Instruments Level 4 Concentration of Credit Risk (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Concentration of Credit Risk [Line Items]
Fair Value, Concentration of Risk, Investments	$ 0
Concentration Risk, Benchmark Description	greater than 10% of the Company's stockholders' equity
Verizon Communications Inc. [Member] \| Corporate Debt Securities [Member]
Concentration of Credit Risk [Line Items]
Largest Exposure by Issuer, Percent of Invested Assets	1.00%	1.00%
HSBC-X UNITED KINGDOM [Member] \| Corporate Debt Securities [Member]
Concentration of Credit Risk [Line Items]
Largest Exposure by Issuer, Percent of Invested Assets	1.00%
BANK OF AMERICA - MERRILL LYNCH ATS [Member] \| Corporate Debt Securities [Member]
Concentration of Credit Risk [Line Items]
Largest Exposure by Issuer, Percent of Invested Assets	1.00%	1.00%
HSBC-X UNITED KINGDOM [Member] \| Corporate Debt Securities [Member]
Concentration of Credit Risk [Line Items]
Largest Exposure by Issuer, Percent of Invested Assets		1.00%
Financial Services [Member] \| Corporate Debt Securities [Member]
Concentration of Credit Risk [Line Items]
Largest Exposure by Sector, Percent of Invested Assets	11.00%	9.00%
Public Utility, Bonds [Member] \| Corporate Debt Securities [Member]
Concentration of Credit Risk [Line Items]
Largest Exposure by Sector, Percent of Invested Assets	8.00%	8.00%
Consumer Non-cyclical [Member] \| Corporate Debt Securities [Member]
Concentration of Credit Risk [Line Items]
Largest Exposure by Sector, Percent of Invested Assets	7.00%	7.00%

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

No definition available.

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

Identifies or describes the benchmark that serves as the denominator in the calculation of the percentage of concentration risk.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13537-108611

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=51801978&loc=d3e6351-108592

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=51801978&loc=d3e6404-108592

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13531-108611

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- Definition

This item represents disclosure of all significant concentrations of credit risk or market risk arising from the subject financial instrument (as defined), whether from an individual counterparty or groups of counterparties.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Trading Securities
-URI http://asc.fasb.org/extlink&oid=6526789

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=51813488&loc=d3e22054-111558

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Available-for-Sale Securities
-URI http://asc.fasb.org/extlink&oid=6505594

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 1
-Subparagraph a, f, g
-Article 7

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