Discontinued Operations (Net Assets Held for Sale) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
Assets held for sale
Fixed maturity investments, at fair value	$ 4,785.5		$ 5,030.5
Cash Including Restricted Cash	543.5		382.8
Reinsurance recoverable on unpaid losses	430.7		428.1
Reinsurance recoverable on paid losses	27.2		25.4
Insurance and reinsurance premiums receivable	677.8		518.9
Deferred acquisition costs	204.4		174.7
Deferred tax asset	439.1		512.1
Other assets	466.7		458.1
Total assets	12,188.3		12,144.3
Liabilities held for sale
Loss and loss adjustment expense reserves	3,022.9	3,053.3	3,079.3	3,108.1	3,057.9	3,168.9
Unearned insurance premiums	1,089.5		901.4
Ceded reinsurance payable	134.0		71.9
Other liabilities	355.4		362.9
Total liabilities	7,689.5		7,746.9
Segment, Discontinued Operations
Assets held for sale
Fixed maturity investments, at fair value	203.9		236.3
Reinsurance recoverable on unpaid losses	1,458.4		1,604.7
Reinsurance recoverable on paid losses	7.4		10.7
Insurance and reinsurance premiums receivable	11.6		9.1
Deferred tax asset	2.5		3.3
Other assets	15.4		16.0
Total assets	1,699.2		1,880.1
Liabilities held for sale
Loss and loss adjustment expense reserves	1,600.9		1,793.1
Unearned insurance premiums	0		0.2
Ceded reinsurance payable	12.1		12.3
Other liabilities	86.2		74.5
Total liabilities	1,699.2		1,880.1
Net assets held for sale	$ 0		$ 0