Investments (Troubled Debt Restructurings on Financing Receivables) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014 NumberOfLoans	Dec. 31, 2013 NumberOfLoans
Financing Receivable, Modifications [Line Items]
Number of Loans	54	22
Pre - Restructuring Recorded Investment	$ 50.2	$ 24.7
Post - Restructuring Recorded Investment	48.7	25.6
Retail [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	45	16
Pre - Restructuring Recorded Investment	42.7	20.0
Post - Restructuring Recorded Investment	40.9	20.8
Office [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	3	3
Pre - Restructuring Recorded Investment	1.4	1.6
Post - Restructuring Recorded Investment	1.2	1.6
Industrial [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	4	2
Pre - Restructuring Recorded Investment	3.1	2.2
Post - Restructuring Recorded Investment	3.4	2.3
Hotels And Motels [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	0
Pre - Restructuring Recorded Investment	0
Post - Restructuring Recorded Investment	0
Commercial [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	2	1
Pre - Restructuring Recorded Investment	3.0	0.9
Post - Restructuring Recorded Investment	3.2	0.9
Apartment And Other [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	0
Pre - Restructuring Recorded Investment	0
Post - Restructuring Recorded Investment	$ 0

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Number of financing receivables that have been modified by troubled debt restructurings.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 33

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953676-111524

+ Details

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- Definition

Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

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- Definition

Pre-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

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