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Retirement Benefits and Trusteed Assets (Pension Plan - Target Allocations of Plan Assets) (Details) (Pension Plan)
12 Months Ended
Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]  
Target Allocation Percentage of Assets 100.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
US Large Cap Equity Securities [Member]
 
Defined Benefit Plan Disclosure [Line Items]  
Target Allocation Percentage of Assets 22.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= dte_USLargeCapEquitySecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
US Small Cap and Mid Cap Equity Securities [Member]
 
Defined Benefit Plan Disclosure [Line Items]  
Target Allocation Percentage of Assets 5.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= dte_UsSmallCapAndMidCapEquitySecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
Non US Equity Securities [Member]
 
Defined Benefit Plan Disclosure [Line Items]  
Target Allocation Percentage of Assets 20.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= dte_NonUsEquitySecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
Fixed Income Securities [Member]
 
Defined Benefit Plan Disclosure [Line Items]  
Target Allocation Percentage of Assets 25.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_FixedIncomeSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
Hedge Funds [Member]
 
Defined Benefit Plan Disclosure [Line Items]  
Target Allocation Percentage of Assets 20.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_HedgeFundsMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
Private Equity Funds [Member]
 
Defined Benefit Plan Disclosure [Line Items]  
Target Allocation Percentage of Assets 8.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_PrivateEquityFundsMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember