XML 116 R80.htm IDEA: XBRL DOCUMENT v2.4.1.9
Fair Value (Reconciliation of Level 3 Assets and Liabilities at Fair Value on a Recurring Basis) (Details) (USD $)
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]    
Net Assets (Liabilities) as of December 31 $ (36,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs $ (13,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs
Transfers into Level 3 from Level 2 0us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersIntoLevel3 1,000,000us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersIntoLevel3
Transfers from Level 3 into Level 2 (2,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersOutOfLevel3 0us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersOutOfLevel3
Total gains (losses):    
Included in earnings (20,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings 43,000,000us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings
Recorded in regulatory assets/liabilities 8,000,000dte_FairValueNetDerivativeAssetLiabilityMeasuredonRecurringBasisUnobservableInputsReconciliationGainsLossesRecordedInRegulatoryAssetsLiabilities 5,000,000dte_FairValueNetDerivativeAssetLiabilityMeasuredonRecurringBasisUnobservableInputsReconciliationGainsLossesRecordedInRegulatoryAssetsLiabilities
Purchases, issuances and settlements:    
Purchases 1,000,000us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchases (7,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchases
Issuances (3,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationIssues (1,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationIssues
Settlements 76,000,000us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements (64,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements
Net Assets (Liabilities) as of December 31 24,000,000us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs (36,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs
The amount of total gains (losses) included in net income attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2014 and 2013 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations 40,000,000us-gaap_FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss (1,000,000)us-gaap_FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss
Natural Gas Commodity Contract [Member]    
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]    
Net Assets (Liabilities) as of December 31 (52,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_NaturalGasCommodityContractMember		 (38,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_NaturalGasCommodityContractMember
Transfers into Level 3 from Level 2 0us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersIntoLevel3
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_NaturalGasCommodityContractMember		 1,000,000us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersIntoLevel3
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_NaturalGasCommodityContractMember
Transfers from Level 3 into Level 2 (2,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersOutOfLevel3
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_NaturalGasCommodityContractMember		 0us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersOutOfLevel3
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_NaturalGasCommodityContractMember
Total gains (losses):    
Included in earnings (40,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_NaturalGasCommodityContractMember		 (32,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_NaturalGasCommodityContractMember
Recorded in regulatory assets/liabilities 0dte_FairValueNetDerivativeAssetLiabilityMeasuredonRecurringBasisUnobservableInputsReconciliationGainsLossesRecordedInRegulatoryAssetsLiabilities
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_NaturalGasCommodityContractMember		 0dte_FairValueNetDerivativeAssetLiabilityMeasuredonRecurringBasisUnobservableInputsReconciliationGainsLossesRecordedInRegulatoryAssetsLiabilities
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_NaturalGasCommodityContractMember
Purchases, issuances and settlements:    
Purchases 0us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchases
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_NaturalGasCommodityContractMember		 (8,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchases
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_NaturalGasCommodityContractMember
Issuances 0us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationIssues
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_NaturalGasCommodityContractMember		 0us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationIssues
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_NaturalGasCommodityContractMember
Settlements 124,000,000us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_NaturalGasCommodityContractMember		 25,000,000us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_NaturalGasCommodityContractMember
Net Assets (Liabilities) as of December 31 30,000,000us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_NaturalGasCommodityContractMember		 (52,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_NaturalGasCommodityContractMember
The amount of total gains (losses) included in net income attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2014 and 2013 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations 35,000,000us-gaap_FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_NaturalGasCommodityContractMember		 (49,000,000)us-gaap_FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_NaturalGasCommodityContractMember
Electricity Commodity Contract [Member]    
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]    
Net Assets (Liabilities) as of December 31 13,000,000us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_ElectricityCommodityContractMember		 23,000,000us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_ElectricityCommodityContractMember
Transfers into Level 3 from Level 2 0us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersIntoLevel3
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_ElectricityCommodityContractMember		 0us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersIntoLevel3
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_ElectricityCommodityContractMember
Transfers from Level 3 into Level 2 0us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersOutOfLevel3
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_ElectricityCommodityContractMember		 0us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersOutOfLevel3
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_ElectricityCommodityContractMember
Total gains (losses):    
Included in earnings 25,000,000us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_ElectricityCommodityContractMember		 75,000,000us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_ElectricityCommodityContractMember
Recorded in regulatory assets/liabilities 0dte_FairValueNetDerivativeAssetLiabilityMeasuredonRecurringBasisUnobservableInputsReconciliationGainsLossesRecordedInRegulatoryAssetsLiabilities
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_ElectricityCommodityContractMember		 0dte_FairValueNetDerivativeAssetLiabilityMeasuredonRecurringBasisUnobservableInputsReconciliationGainsLossesRecordedInRegulatoryAssetsLiabilities
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_ElectricityCommodityContractMember
Purchases, issuances and settlements:    
Purchases 1,000,000us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchases
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_ElectricityCommodityContractMember		 1,000,000us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchases
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_ElectricityCommodityContractMember
Issuances (3,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationIssues
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_ElectricityCommodityContractMember		 (1,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationIssues
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_ElectricityCommodityContractMember
Settlements (41,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_ElectricityCommodityContractMember		 (85,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_ElectricityCommodityContractMember
Net Assets (Liabilities) as of December 31 (5,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_ElectricityCommodityContractMember		 13,000,000us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_ElectricityCommodityContractMember
The amount of total gains (losses) included in net income attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2014 and 2013 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations 9,000,000us-gaap_FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_ElectricityCommodityContractMember		 48,000,000us-gaap_FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_ElectricityCommodityContractMember
Other Commodity Contract [Member]    
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]    
Net Assets (Liabilities) as of December 31 3,000,000us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_OtherCommodityContractMember		 2,000,000us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_OtherCommodityContractMember
Transfers into Level 3 from Level 2 0us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersIntoLevel3
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_OtherCommodityContractMember		 0us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersIntoLevel3
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_OtherCommodityContractMember
Transfers from Level 3 into Level 2 0us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersOutOfLevel3
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_OtherCommodityContractMember		 0us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersOutOfLevel3
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_OtherCommodityContractMember
Total gains (losses):    
Included in earnings (5,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_OtherCommodityContractMember		 0us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_OtherCommodityContractMember
Recorded in regulatory assets/liabilities 8,000,000dte_FairValueNetDerivativeAssetLiabilityMeasuredonRecurringBasisUnobservableInputsReconciliationGainsLossesRecordedInRegulatoryAssetsLiabilities
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_OtherCommodityContractMember		 5,000,000dte_FairValueNetDerivativeAssetLiabilityMeasuredonRecurringBasisUnobservableInputsReconciliationGainsLossesRecordedInRegulatoryAssetsLiabilities
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_OtherCommodityContractMember
Purchases, issuances and settlements:    
Purchases 0us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchases
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_OtherCommodityContractMember		 0us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchases
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_OtherCommodityContractMember
Issuances 0us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationIssues
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_OtherCommodityContractMember		 0us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationIssues
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_OtherCommodityContractMember
Settlements (7,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_OtherCommodityContractMember		 (4,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_OtherCommodityContractMember
Net Assets (Liabilities) as of December 31 (1,000,000)us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_OtherCommodityContractMember		 3,000,000us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_OtherCommodityContractMember
The amount of total gains (losses) included in net income attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2014 and 2013 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations $ (4,000,000)us-gaap_FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_OtherCommodityContractMember		 $ 0us-gaap_FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss
/ us-gaap_DerivativeInstrumentRiskAxis
= dte_OtherCommodityContractMember