Supplemental Cash Flow Information Significant Non-Cash Investing Activities(Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]
Outstanding receivables from outside parties for the funding of capital expenditures	$ 32.1	$ 33.0	$ 25.0
Purchases of property and equipment accrued in accounts payable	$ 51.3	$ 40.1	$ 22.6