Derivative Instruments And Hedging Activities Notional Contracts by Derivative Type (Details) - Economic Hedges [Member]	9 Months Ended
	Sep. 30, 2015 MMBTU bbl
Commodity Contract [Member]
Economic hedges by derivative type [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net | bbl	5,866,000
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	1,840,000
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	4,026,000
Natural Gas Liquids [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure	22,626,000
Natural Gas Liquids [Member] | Maturing in Next Twelve Months [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure	2,010,000
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
Natural Gas Liquids [Member] | Maturing in Year Three [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure	10,308,000
Natural Gas - long [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure	21,600,000
Natural Gas - long [Member] | Maturing in Next Twelve Months [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure	2,400,000
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
Natural Gas - long [Member] | Maturing in Year Three [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure	9,600,000
Natural Gas - Short [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure	21,600,000
Natural Gas - Short [Member] | Maturing in Next Twelve Months [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure	2,400,000
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
Natural Gas - Short [Member] | Maturing in Year Three [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure	9,600,000
NYMEX WTI short [Member]
Economic hedges by derivative type [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net | bbl	1,760,000
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	1,083,000
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	677,000
Physical Contracts - Short [Member]
Economic hedges by derivative type [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net | bbl	150,000
Physical Contracts - 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	150,000