v2.4.0.8

Derivative and Hedging Activities Derivative and Hedging Activities - Quantitative Disclosures Level 3 Table (Details) (USD $) In Millions, unless otherwise specified | 6 Months Ended
--- | ---
Jun. 30, 2014
Natural Gas [Member] |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value | $ (218)
Natural Gas [Member] | Minimum [Member] |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |
Weighted Average Of Price Volatility Curve Percentage | 19.54%
Natural Gas [Member] | Maximum [Member] |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |
Weighted Average Of Price Volatility Curve Percentage | 38.70%
Natural Gas [Member] | Weighted Average [Member] |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |
Weighted Average Of Price Volatility Curve Percentage | 24.43%
Crude Oil [Member] |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value | $ (332)
Crude Oil [Member] | Minimum [Member] |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |
Weighted Average Of Price Volatility Curve Percentage | 9.12%
Crude Oil [Member] | Maximum [Member] |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |
Weighted Average Of Price Volatility Curve Percentage | 18.73%
Crude Oil [Member] | Weighted Average [Member] |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |
Weighted Average Of Price Volatility Curve Percentage | 14.63%

X
- Definition Weighted average expected volatility of stock price. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueAssumptionsWeightedAverageVolatilityRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FairValueInputsAssetsQuantitativeInformationLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant