Contingencies (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended		26 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2013 bbl	Mar. 31, 2015
Loss Contingencies [Line Items]
Promissory notes provided as collateral for letters of credit	$ 79.4	$ 86.3		$ 79.4
Pending Litigation Escopetrol [Member]
Loss Contingencies [Line Items]
Loss in period in barrels of oil			44,025
Contingent consideration liability	2.4	2.4
Pending Litigation Moqueta Discovery [Member]
Loss Contingencies [Line Items]
Contingent consideration liability	65.6
Related interest costs				21.3
Royalty agreement basis spread on variable rate	4.00%			4.00%
Related interest	4.2
Contested interest rate (percent)	29.00%			29.00%
Threshold by which additional royalty due (barrels)	5,000,000
Total cumulative production of oil field (barrels)	4,800,000
Pending Litigation Royalty, Transportation and Related Costs [Member]
Loss Contingencies [Line Items]
Contingent consideration liability	$ 41.2