Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Income Tax Disclosure [Abstract]
Effective income tax rate (as a percent)	34.40%	(18.10%)
Unrecognized income tax benefits including interest and penalties	$ 30.1
Portion of unrecognized income tax benefits, expected to be recognized upon settlement of tax examinations and the expiration of various statutes of limitations within next twelve months	$ 3.9