Discontinued Operations Discontinued Operations (Cash Flows Table) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash Provided by (Used in) Operating Activities, Discontinued Operations	$ (24.7)	$ 56.0	$ 48.9
Cash Provided by (Used in) Investing Activities, Discontinued Operations	221.7	(5.4)	51.2
Cash Provided by (Used in) Financing Activities, Discontinued Operations	(0.2)	(11.6)	(64.5)
Net Cash Provided by (Used in) Discontinued Operations	196.8	34.5	21.3
Cash balance at beginning of year	167.2	232.7	233.5
Cash and Cash Equivalents, Period Increase (Decrease)	(17.7)	(66.6)	1.5
Cash balance at end of year	149.8	167.2	232.7
Sirius Group
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Effect of Exchange Rate on Cash	0.0	(4.5)	(14.3)
Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash balance at beginning of year	150.2	116.8	93.2
Cash and Cash Equivalents, Period Increase (Decrease)	(0.3)	(1.1)	2.3
Cash Divested from Deconsolidation	345.8
Cash balance at end of year	$ 0.9	$ 150.2	$ 116.8