Derivatives Derivatives by Balance Sheet Location (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Notional Disclosures [Abstract]
Derivative, Nonmonetary Notional Amount (billion cubic feet)	279.3
Commodity Contract [Member] \| Cash Flow Hedging [Member] \| Assets, Total [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 83,661	$ 135,969
Derivative Liability, Fair Value, Gross Liability		7,024
Commodity Contract [Member] \| Cash Flow Hedging [Member] \| Prepaid Expenses [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets, Current	59,605	80,057
Commodity Contract [Member] \| Cash Flow Hedging [Member] \| Other Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets, Noncurrent	24,056	55,912
Commodity Contract [Member] \| Cash Flow Hedging [Member] \| Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities, Current		970
Commodity Contract [Member] \| Cash Flow Hedging [Member] \| Liabilities, Total [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	18,212
Commodity Contract [Member] \| Cash Flow Hedging [Member] \| Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities, Current	12,327
Commodity Contract [Member] \| Cash Flow Hedging [Member] \| Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities, Noncurrent	$ 5,885	$ 6,054

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References+ Details

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References+ Details

- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References+ Details

- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References+ Details