Business Segments - Earned Premiums by Product Line (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Entity-Wide Information, Revenue from External Customer [Line Items]
Premiums Earned, Net, Life									$ 392.7	$ 393.4	$ 395.1
Premiums Earned, Net, Accident and Health									161.4	165.2	166.3
Earned Premiums	495.6	507.5	512.8	509.9	520.8	527.3	529.8	529.2	2,025.8	2,107.1	2,173.6
Personal Lines [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Premiums Earned, Net, Property and Casualty									1,419.4	1,505.0	1,572.2
Automobile [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Premiums Earned, Net, Property and Casualty									959.1	1,050.1	1,129.4
Homeowners [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Premiums Earned, Net, Property and Casualty									326.2	318.0	304.1
Other Personal Lines [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Premiums Earned, Net, Property and Casualty									134.1	136.9	138.7
Commercial Automobile [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Premiums Earned, Net, Property and Casualty									$ 52.3	$ 43.5	$ 40.0