Summary of Significant Accounting Policies Deferred Policy Acquisition Costs (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Business Acquisition [Line Items]
Deferred policy acquisition cost, written off			$ 29.1
Deferred beginning of year	165.5	197.6	230.6
Acquisition costs deferred; additions	359.1	311.0	338.4
Amortization charged to income	(331.9)	(343.2)	(371.7)
Change for the year	27.1	(32.1)	(33.3)
Deferred end of year	192.6	165.5	197.6
Commissions, net of reinsurance [Member]
Business Acquisition [Line Items]
Acquisition costs deferred; additions	222.7	180.8	139.0
Premium taxes [Member]
Business Acquisition [Line Items]
Acquisition costs deferred; additions	93.8	86.8	77.7
Salaries and other marketing expenses [Member]
Business Acquisition [Line Items]
Acquisition costs deferred; additions	42.5	43.3	121.8
General Insurance Group [Member]
Business Acquisition [Line Items]
Deferred policy acquisition costs, charges relating to adoption of new accounting guidance		$ 37.9