Derivatives (Derivatives Outstanding) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014
Derivative [Line Items]
Total mark to market derivatives	$ (0.8)
Short Contracts | Liquids
Derivative [Line Items]
Derivative Nonmonetary Notional Amount	(69,000,000)
Total mark to market derivatives	(0.5)
Short Contracts | Condensate Inventory
Derivative [Line Items]
Derivative Nonmonetary Notional Amount	(100,000)
Total mark to market derivatives	0.1
Long Contracts | Liquids
Derivative [Line Items]
Derivative Nonmonetary Notional Amount	(54,800,000)
Total mark to market derivatives	(0.5)
Long Contracts | Gas
Derivative [Line Items]
Derivative Nonmonetary Notional Amount	(300,000)
Total mark to market derivatives	0.1
Commodity
Derivative [Line Items]
Total mark to market derivatives	$ (0.8)