Fair Value Disclosures (Carrying Value And Fair Value Of The Financial Instruments That Are Not Recognized Or Are Not Carried At Fair Value) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Financial Liabilities
Funds held under reinsurance	$ 272.0	$ 179.8
Nonrecurring
Financial Assets
Commercial mortgage loans on real estate	735.1	679.2
Other investments	124.9	84.4
Other assets	43.0
Total financial assets	903.0	763.6
Financial Liabilities
Policy reserves under investment products (Individual and group annuities, subject to discretionary withdrawal)	556.8	642.5
Funds held under reinsurance	272.0	179.8
Debt	2,058.7	1,174.4
Total financial liabilities	2,887.5	1,996.7
Level 1 \| Nonrecurring
Financial Assets
Commercial mortgage loans on real estate	0.0	0.0
Other investments	33.9	36.3
Other assets	0.0
Total financial assets	33.9	36.3
Financial Liabilities
Policy reserves under investment products (Individual and group annuities, subject to discretionary withdrawal)	0.0	0.0
Funds held under reinsurance	272.0	179.8
Debt	0.0	0.0
Total financial liabilities	272.0	179.8
Level 2 \| Nonrecurring
Financial Assets
Commercial mortgage loans on real estate	0.0	0.0
Other investments	0.0	0.0
Other assets	0.0
Total financial assets	0.0	0.0
Financial Liabilities
Policy reserves under investment products (Individual and group annuities, subject to discretionary withdrawal)	0.0	0.0
Funds held under reinsurance	0.0	0.0
Debt	2,058.7	1,174.4
Total financial liabilities	2,058.7	1,174.4
Level 3 \| Nonrecurring
Financial Assets
Commercial mortgage loans on real estate	735.1	679.2
Other investments	91.0	48.1
Other assets	43.0
Total financial assets	869.1	727.3
Financial Liabilities
Policy reserves under investment products (Individual and group annuities, subject to discretionary withdrawal)	556.8	642.5
Funds held under reinsurance	0.0	0.0
Debt	0.0	0.0
Total financial liabilities	556.8	642.5
Carrying Value \| Nonrecurring
Financial Assets
Commercial mortgage loans on real estate	759.6	670.2
Other investments	124.9	84.4
Other assets	43.0
Total financial assets	927.5	754.6
Financial Liabilities
Policy reserves under investment products (Individual and group annuities, subject to discretionary withdrawal)	570.6	634.3
Funds held under reinsurance	272.0	179.8
Debt	2,006.0	1,068.2
Total financial liabilities	$ 2,848.6	$ 1,882.3

Policy Reserves Under Investment Products, Fair Value Disclosure

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- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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- References

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- Definition

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611

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Fair value of financial obligations, including, but not limited to, debt instruments, derivative liabilities, federal funds purchased and sold under agreements to repurchase, securities loaned or sold under agreements to repurchase, financial instruments sold not yet purchased, guarantees, line of credit, loans and notes payable, servicing liability, and trading liabilities.

+ References

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- Definition

Amount of funds held as security for payments to be received under reinsurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.13(c))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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- Definition

Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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- Definition

Fair value portion of mortgage loans held-for-sale.

+ References

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- Definition

Fair value portion of other assets.

+ References

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