Significant Non-Cash Investing Activities (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Significant Non Cash Investing Activities [Abstract]
Grant receivables from outside parties for capital expenditures	$ 17.8	$ 11.5
Purchases of property and equipment accrued in accounts payable	$ 14.0	$ 6.2