Derivative Instruments And Hedging Activities Volumes related to price risk purchase derivatives (Details) - 6 months ended Jun. 30, 2015	MMBTU bbl
Natural Gas - long [Member]
Price Risk Derivatives for Future Purchases Notional Contract Volumes [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU	24,000,000
WTI Crude Oil [Member]
Price Risk Derivatives for Future Purchases Notional Contract Volumes [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net	2,208,000
Ultra Low Sulfur Diesel [Member]
Price Risk Derivatives for Future Purchases Notional Contract Volumes [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net	2,208,000
Forward Contracts [Member]
Price Risk Derivatives for Future Purchases Notional Contract Volumes [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net	1,500,000
Future [Member]
Price Risk Derivatives for Future Purchases Notional Contract Volumes [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net	1,125,000
Maturing in Next Twelve Months [Member] | Natural Gas - long [Member]
Price Risk Derivatives for Future Purchases Notional Contract Volumes [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU	4,800,000
Maturing in Next Twelve Months [Member] | WTI Crude Oil [Member]
Price Risk Derivatives for Future Purchases Notional Contract Volumes [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net	2,208,000
Maturing in Next Twelve Months [Member] | Ultra Low Sulfur Diesel [Member]
Price Risk Derivatives for Future Purchases Notional Contract Volumes [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net	2,208,000
Maturing in Next Twelve Months [Member] | Forward Contracts [Member]
Price Risk Derivatives for Future Purchases Notional Contract Volumes [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net	1,500,000
Maturing in Next Twelve Months [Member] | Future [Member]
Price Risk Derivatives for Future Purchases Notional Contract Volumes [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net	1,125,000
Maturing in Year Two [Member] | Natural Gas - long [Member]
Price Risk Derivatives for Future Purchases Notional Contract Volumes [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU	9,600,000
Maturing in Year Three [Member] | Natural Gas - long [Member]
Price Risk Derivatives for Future Purchases Notional Contract Volumes [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU	9,600,000