Investments Federal Home Loan Bank Carrying Amount, Collateral Posted and Advances Received (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Federal Home Loan Bank Carrying Value of Common Stock, Collateral Posted and Advances
Federal Home Loan Bank Stock	$ 32.1	$ 34.1
Federal Home Loan Bank (FHLB) Funding Agreements	272.0	350.0
Collateral Pledged to Federal Home Loan Bank (FHLB)	515.5	544.8
Fixed Maturity Securities
Federal Home Loan Bank Carrying Value of Common Stock, Collateral Posted and Advances
Collateral Pledged to Federal Home Loan Bank (FHLB)	223.8	213.3
Mortgage Loans as Collateral
Federal Home Loan Bank Carrying Value of Common Stock, Collateral Posted and Advances
Collateral Pledged to Federal Home Loan Bank (FHLB)	$ 291.7	$ 331.5

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- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-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

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- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

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- Definition

Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 325
-Section 45
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-URI http://asc.fasb.org/extlink&oid=75031641&loc=d3e63345-112809

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