Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Income Tax Contingency [Line Items]
Unrecognized tax benefits	$ 114.1
Interest expense or penalties, uncertain tax positions	0	0
Accrued interest, uncertain tax positions	0.4		0.4
Unrecognized tax benefits that would impact effective tax rate	$ 79.5
Internal Revenue Service (IRS) [Member]
Income Tax Contingency [Line Items]
Earliest year subject to examination	2000