Business Segments - Amortization of Deferred Policy Acquisitions Costs By Segment (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Amortization of Deferred Policy Acquisition Costs	$ 235.4	$ 253.9	$ 257.0
Operating Segments [Member]
Segment Reporting Information [Line Items]
Amortization of Deferred Policy Acquisition Costs	235.4	253.9	257.0
Property and Casualty Insurance [Member]
Segment Reporting Information [Line Items]
Amortization of Deferred Policy Acquisition Costs	187.5	207.2	212.6
Life and Health Insurance [Member]
Segment Reporting Information [Line Items]
Amortization of Deferred Policy Acquisition Costs	$ 47.9	$ 46.7	$ 44.4