Schedule VI - Supplemental Information Concerning Property-Casualty Insurance Operations (Details) (Consolidated Property and Casualty Insurance Entity [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Consolidated Property and Casualty Insurance Entity [Member]
Supplemental Information for Property, Casualty Insurance Underwriters
Deferred Policy Acquisition Costs	$ 170.4	[1]	$ 139.4	[1]	$ 168.6	[1]
Reserves for Unpaid Claims and Claims Adjustment Expenses	4,400.3	[1],[2]	4,119.2	[1],[2]	3,928.1	[1],[2]
Discount If Any Deducted From Reserves	241.4	[1]	230.8	[1]	235.1	[1]
Unearned Premiums	1,174.2	[1],[2]	1,068.8	[1],[2]	1,009.2	[1],[2]
Earned Premiums	2,543.5	[1]	2,366.9	[1]	2,167.7	[1]
Net Investment Income	250.0	[1]	265.0	[1]	270.5	[1]
Current Year Claims and Claims Adjustment Expenses	1,919.1	[1]	1,810.8	[1]	1,678.5	[1]
Prior Year Claims and Claims Adjustment Expenses	(40.4)	[1]	(19.8)	[1]	(149.2)	[1]
Amortization of Deferred Policy Acquisition Costs	315.4	[1]	327.9	[1]	298.9	[1]
Paid Claims and Claims Adjustment Expenses	1,597.5	[1]	1,577.9	[1]	1,551.1	[1]
Premiums Written	$ 2,630.3	[1]	$ 2,405.8	[1]	$ 2,220.7	[1]

[1] Includes consolidated property-casualty entities. The amounts relating to the Company's unconsolidated property-casualty subsidiaries and the proportionate share of the registrant's and its subsidiaries' 50%-or-less owned property-casualty equity investees are immaterial and have, therefore, been omitted from this schedule.

[2] See note (2) to Schedule III.