Accounts Payable and Accrued Liabilities (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Accounts Payable and Accrued Liabilities [Abstract]
Commodities	$ 528.1	$ 520.8
Other goods and services	109.7	146.8
Interest	42.4	35.9
Compensation and benefits	23.5	40.3
Income and other taxes	32.8	10.2
Other	9.0	7.8
Total accounts payable and accrued liabilities	$ 745.5	$ 761.8