Insurance (Obligations Under Funding Agreements - Liability and Collateral) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Fixed and Floating Rate Funding Agreements by Type [Line Items]
Outstanding funding agreements to certain SPEs	$ 100	$ 2,200
Invested Assets Pledged As Collateral	3,548	2,801
Federal Home Loan Bank of Boston
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Federal Home Loan Bank amount of advances by branch for funding agreements	50	250
Collateral pledged relating to obligations under funding agreements	144	311
Federal Home Loan Bank of Des Moines
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Federal Home Loan Bank amount of advances by branch for funding agreements	95	95
Collateral pledged relating to obligations under funding agreements	266	147
Federal Home Loan Bank of Pittsburgh
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Federal Home Loan Bank amount of advances by branch for funding agreements	500	1,570
Collateral pledged relating to obligations under funding agreements	$ 3,765	$ 1,789

Fixed and Floating Rate Funding Agreements by Type.

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- Definition

Invested assets pledged as collateral.

+ References

No definition available.

+ Details

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- Definition

Amount of funding agreements outstanding to certain SPEs that have issued debt securities for which payment of interest and principal is secured by such funding agreements.

+ References

No definition available.

+ Details

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- Definition

Amount of advances from the Federal Home Loan Bank (FHLB).

+ References

+ 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

Amount of the collateral pledged in support of federal home loan bank advances outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

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