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Schedule of Components of Unrealized Gain (Loss) on Securities (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2018 | Mar. 31, 2017
Change in Components of Net Unrealized Gain on Securities |  |
Change in Net Unrealized Gain on Securities | $ (1,042.1) | $ 176.9
Fixed Maturity Securities |  |
Change in Components of Net Unrealized Gain on Securities |  |
Beginning of Period Balance | 5,665.2 | 4,664.6
Change in Net Unrealized Gain on Securities | (1,317.0) | 261.0
End of Period Balance | 4,348.2 | 4,925.6
Other Investments |  |
Change in Components of Net Unrealized Gain on Securities |  |
Beginning of Period Balance |  | (22.7)
Change in Net Unrealized Gain on Securities |  | 4.9
End of Period Balance |  | (17.8)
Deferred Acquisition Costs |  |
Change in Components of Net Unrealized Gain on Securities |  |
Beginning of Period Balance | (51.4) | (38.9)
Change in Net Unrealized Gain on Securities | 10.2 | (2.0)
End of Period Balance | (41.2) | (40.9)
Reserve for Future Policy and Contract Benefits |  |
Change in Components of Net Unrealized Gain on Securities |  |
Beginning of Period Balance | (5,094.7) | (4,253.2)
Change in Net Unrealized Gain on Securities | 1,064.6 | (214.1)
End of Period Balance | (4,030.1) | (4,467.3)
Reinsurance Recoverable |  |
Change in Components of Net Unrealized Gain on Securities |  |
Beginning of Period Balance | 375.8 | 321.3
Change in Net Unrealized Gain on Securities | (54.8) | 14.3
End of Period Balance | 321.0 | 335.6
Income Tax |  |
Change in Components of Net Unrealized Gain on Securities |  |
Beginning of Period Balance | (304.6) | (230.5)
Change in Net Unrealized Gain on Securities | 62.8 | (21.7)
End of Period Balance | (241.8) | (252.2)
Net Unrealized Gain on Securities |  |
Change in Components of Net Unrealized Gain on Securities |  |
Beginning of Period Balance | 590.3 | 440.6
Change in Net Unrealized Gain on Securities | (234.2) | 42.4
End of Period Balance | $ 356.1 | $ 483.0

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- Definition Accumulated appreciation or loss, net of tax, in value of the total of available-for-sale securities at the end of an accounting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669686-108580 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e637-108580 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14 -URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e681-108580 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 10A -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669646-108580 + Details
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