Fair Value (Schedule Of Gain And Losses Due To Change In Fair Value Level 3 Assets) (Details) (Level 3 [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other-than-temporary impairments	$ (0.1)	$ (0.5)
Net realized investment gains	(0.1)
Total	(0.2)	(0.5)
Fixed Maturities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other-than-temporary impairments	(0.1)
Net realized investment gains	0.1
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other-than-temporary impairments		(0.5)
Net realized investment gains	(0.2)
Total	(0.2)	(0.5)
Asset-Backed [Member] | Fixed Maturities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other-than-temporary impairments	(0.1)
Net realized investment gains
Total	(0.1)
Corporate [Member] | Fixed Maturities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized investment gains	0.1
Total	$ 0.1