Supplemental Cash Flow Information (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Significant Non Cash Investing Activities [Abstract]
Grant receivables from outside parties for capital expenditures	$ 20.8	$ 17.0	$ 15.7
Purchases of property and equipment accrued in accounts payable	$ 17.6	$ 11.7