Derivative Instruments And Hedging Activities Notional Contracts by Derivative Type (Details)	3 Months Ended
	Mar. 31, 2016 MMBTU bbl
Economic Hedges [Member] | Commodity Contract [Member]
Economic hedges by derivative type [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net | bbl	8,800,000
Economic Hedges [Member] | Commodity Contract [Member] | Maturing in Next Twelve Months [Member]
Economic hedges by derivative type [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net | bbl	8,800,000
Economic Hedges [Member] | Commodity Contract [Member] | Maturing in Year Two [Member]
Economic hedges by derivative type [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net | bbl	0
Economic Hedges [Member] | Natural Gas Liquids [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure	18,039,000
Economic Hedges [Member] | Natural Gas Liquids [Member] | Maturing in Next Twelve Months [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure	7,731,000
Economic Hedges [Member] | Natural Gas Liquids [Member] | Maturing in Year Two [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure	10,308,000
Economic Hedges [Member] | Natural Gas - long [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure	16,800,000
Economic Hedges [Member] | Natural Gas - long [Member] | Maturing in Next Twelve Months [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure	7,200,000
Economic Hedges [Member] | Natural Gas - long [Member] | Maturing in Year Two [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure	9,600,000
Economic Hedges [Member] | Natural Gas - Short [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure	16,800,000
Economic Hedges [Member] | Natural Gas - Short [Member] | Maturing in Next Twelve Months [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure	7,200,000
Economic Hedges [Member] | Natural Gas - Short [Member] | Maturing in Year Two [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure	9,600,000
Economic Hedges [Member] | NYMEX WTI short [Member]
Economic hedges by derivative type [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net | bbl	910,000
Economic Hedges [Member] | NYMEX WTI short [Member] | Maturing in Next Twelve Months [Member]
Economic hedges by derivative type [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net | bbl	910,000
Economic Hedges [Member] | NYMEX WTI short [Member] | Maturing in Year Two [Member]
Economic hedges by derivative type [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net | bbl	0
Economic Hedges [Member] | Forward Contracts [Member]
Economic hedges by derivative type [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net | bbl	1,175,000
Economic Hedges [Member] | Forward Contracts [Member] | Maturing in Next Twelve Months [Member]
Economic hedges by derivative type [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net | bbl	1,175,000
Price Risk Derivative [Member] | Natural Gas - long [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure	16,800,000
Price Risk Derivative [Member] | Natural Gas - long [Member] | Maturing in Next Twelve Months [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure	7,200,000
Price Risk Derivative [Member] | Natural Gas - long [Member] | Maturing in Year Two [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure	9,600,000