Supplemental Cash Flow Information (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Supplemental Cash Flow [Line Items]    
Capital expenditures included in current liabilities [1] $ 119.2 $ 98.8
Cash paid for interest, net of interest capitalized amounts $ 7.5 $ 15.6
[1] Capital expenditures included in current liabilities is comprised of "Accrued capital expenditures" and certain other amounts included within "Accounts payable" on the Condensed Consolidated Balance Sheets (unaudited).