XML 74 R39.htm IDEA: XBRL DOCUMENT v2.4.1.9
Significant Accounting Policies (Details Textuals) (USD $)
In Millions, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2014
Significant Accounting Policies [Line Items]      
Other income $ 51us-gaap_OtherNonoperatingIncome $ 41us-gaap_OtherNonoperatingIncome  
Increase (decrease) in effective tax rate from prior year (2.00%)dte_IncreaseDecreaseinEffectiveTaxRatefromPriorYearPercent    
Deferred tax expense 8us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes    
Unrecognized tax benefits that would impact effective tax rate 2us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate    
Change in unrecognized tax benefits is reasonably possible 6us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleAmountOfUnrecordedBenefit    
DTE Electric      
Significant Accounting Policies [Line Items]      
Other income 15us-gaap_OtherNonoperatingIncome
/ dei_LegalEntityAxis
= dte_DTEElectricMember
13us-gaap_OtherNonoperatingIncome
/ dei_LegalEntityAxis
= dte_DTEElectricMember
 
Increase (decrease) in effective tax rate from prior year (1.00%)dte_IncreaseDecreaseinEffectiveTaxRatefromPriorYearPercent
/ dei_LegalEntityAxis
= dte_DTEElectricMember
   
DTE Electric | DTE Energy      
Significant Accounting Policies [Line Items]      
Income Taxes Receivable 51us-gaap_IncomeTaxReceivable
/ dei_LegalEntityAxis
= dte_DTEElectricMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_ParentCompanyMember
  29us-gaap_IncomeTaxReceivable
/ dei_LegalEntityAxis
= dte_DTEElectricMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_ParentCompanyMember
Minimum      
Significant Accounting Policies [Line Items]      
Useful life 1 year    
Maximum      
Significant Accounting Policies [Line Items]      
Useful life 26 years    
Power and Industrial Projects      
Significant Accounting Policies [Line Items]      
Other income $ 19us-gaap_OtherNonoperatingIncome
/ us-gaap_StatementBusinessSegmentsAxis
= dte_PowerAndIndustrialProjectsMember
$ 17us-gaap_OtherNonoperatingIncome
/ us-gaap_StatementBusinessSegmentsAxis
= dte_PowerAndIndustrialProjectsMember