Investments (Pledged Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Compliance With Reinsurance Contract Provisions Or Insurance Laws [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Restricted Cash and Investments	$ 2,719.8	$ 2,687.7
Pledged As Collateral For Letter Of Credit Facilities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Restricted Cash and Investments	$ 575.3	$ 587.6

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.

No definition available.

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