Significant Non-Cash Investing Activities (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]
Grant receivables from outside parties for capital expenditures	$ 23.2	$ 15.2
Purchases of property and equipment accrued in accounts payable	$ 20.5	$ 16.3