Derivative Instruments And Hedging Activities Notional Contracts by Derivative Type (Details)	Jun. 30, 2013 bbl	Jun. 30, 2012 bbl
economic hedges by derivative type [Line Items]
Nonmonetary Notional Amount of Price Risk Cash Flow Hedge Derivatives	5,048,000
Derivative, Nonmonetary Notional Amount	540,000	4,508,000
Natural Gas [Member]
economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount		6,624,000
Nonmonetary Notional Amount of Price Risk Derivatives	6,624,000
Commodity WCS Spread [Member]
economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount	5,657,500	765,000
Nonmonetary Notional Amount of Price Risk Derivatives	6,422,500
Commodity WTI Long [Member]
economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount	150,000
Nonmonetary Notional Amount of Price Risk Derivatives	150,000
WTI Crude Oil [Member]
economic hedges by derivative type [Line Items]
Nonmonetary Notional Amount of Price Risk Cash Flow Hedge Derivatives	10,096,000
Derivative, Nonmonetary Notional Amount	1,080,000	9,016,000
Commodity Gasoline [Member]
economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount	480,000	150,000
Nonmonetary Notional Amount of Price Risk Derivatives	630,000
Commodity Butane [Member]
economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount		540,000
Nonmonetary Notional Amount of Price Risk Derivatives	540,000
NYMEX WTI Long [Member]
economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount	234,000	146,000
Nonmonetary Notional Amount of Price Risk Derivatives	380,000
NYMEX WTI Short [Member]
economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount		1,008,000
Nonmonetary Notional Amount of Price Risk Derivatives	1,008,000