Discontinued Operations (Summary of Reclassified Balances and Related Items) (Details) (USD $) In Millions, unless otherwise specified						3 Months Ended			3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Mar. 31, 2014 Segment, Discontinued Operations	Mar. 31, 2013 Segment, Discontinued Operations	Dec. 31, 2013 Segment, Discontinued Operations	Mar. 31, 2014 Segment, Discontinued Operations Runoff	Dec. 31, 2013 Segment, Discontinued Operations Runoff
Discontinued Operations
Reinsurance Recoverables, Gross						$ 133.6		$ 136.9
Quota Share Reinsurance Agreement Percentage					100.00%
Assets
Investments	2,415.7	2,364.9							222.2	236.3
Premiums receivable	249.2	228.2							12.8	9.1
Reinsurance recoverable on unpaid losses	80.1	80.2	105.8	107.3		1,673.6		1,741.6	1,540.0	1,604.7
Reinsurance recoverable on paid losses	3.0								9.5	10.7
Net deferred tax asset									3.2	3.3
Other assets	289.9	272.7							15.4	16.0
Total assets	5,181.1	5,211.6							1,803.1	1,880.1
Liabilities
Unpaid loss and loss adjustment expense reserves	1,069.8	1,054.3	1,010.3	1,000.0		1,850.9		1,930.0	1,717.3	1,793.1
Unearned premiums	582.2	544.9							0.2	0.2
Ceded reinsurance payable									12.1	12.3
Other liabilities	292.6	338.6							73.5	74.5
Total liabilities	4,048.0	4,104.2							1,803.1	1,880.1
Pre-tax income (loss)						$ (0.8)	$ 0.7		$ 69.0	$ 69.0