Income Tax Matters, Textuals (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Income tax provision	$ 8.2	$ 16.3
Effective tax rate	19.70%	38.10%
Increase (decrease) in unrecognized tax benefits, including interest and penalties	7.5	(0.1)
Increase (decrease) in effective tax rate due to unrecognized tax benefits, including interest and penalty	(17.90%)	0.30%
Refund adjustment from settlement with Canada Revenue Agency	7.9
Gross unrecognized tax benefits	8.8		15.7
Unrecognized tax benefits that would impact effective tax rate	7.7		14.6
Reduction in gross unrecognized tax benefits	$ 3.5
Expected period which gross unrecognized tax benefits will not be reduced	12 months