Income Taxes (Details Textual) (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2011	Mar. 31, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Income Taxes (Textuals)
Provision for income tax expense (benefit)	$ 11.2		$ (1.3)	$ 3.8	$ 1.1
Income tax expense	12.0		2.9	33.0	5.5
Estimated effective federal and state income tax rate	39.00%			39.00%
Income Tax Benefit Resulting from Settlement of Federal Income Tax Claims	24			24
Income Tax Benefit Resulting from Reduction in Unrecognized Tax Benefits			5.9	5.0	6.5
Reduction in Valuation Allowance		7				825
Valuation Allowance	106			106		113
Value of net deferred tax assets included in the condensed consolidated balance sheet	690.6			690.6
Value of net deferred tax assets included in other current assets	27.9			27.9
Deferred tax expense			1.7	5.2	2.1
Remaining gross unrecognized tax benefits	8.5			8.5		12.6
Accrued interest expense related to unrecognized tax benefits	0.1			0.1		1.1
Net Interest Income (Expense) as Part of Our Income Tax Provision	0.3		1.7	1.8	1.8
Total accrued interest income	$ 0.4			$ 0.4		$ 0.3
Cumulative changes in ownership interests of significant shareholders				over three-year period in excess of 50%