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Long-Term Debt (Long Term Debt Outstanding and Weighted Average Interest Rates) (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Debt Instrument [Line Items]    
Long-term Debt, Total $ 8,620us-gaap_LongTermDebt  
Long Term Debt excluding Securitization, Debentures and Capital Leases 8,021dte_LongTermDebtexcludingSecuritizationDebenturesandCapitalLeases 7,312dte_LongTermDebtexcludingSecuritizationDebenturesandCapitalLeases
Less Amount of Long-term Debt due within one year (161)us-gaap_DebtCurrent (694)us-gaap_DebtCurrent
Long-term Debt, Excluding Current Maturities 7,860us-gaap_LongTermDebtNoncurrent 6,618us-gaap_LongTermDebtNoncurrent
Less Amount of Securitization Bonds due within one year (105)dte_SecuritizationBondsCurrent (197)dte_SecuritizationBondsCurrent
Securitization bonds, Excluding Current Maturities 0dte_Securitizationbondsnoncurrent 105dte_Securitizationbondsnoncurrent
Junior Subordinated Notes, Noncurrent 480us-gaap_JuniorSubordinatedLongTermNotes 480us-gaap_JuniorSubordinatedLongTermNotes
6.6% Securitization Bonds Due 2015 [Member]    
Debt Instrument [Line Items]    
Debt, Weighted Average Interest Rate 6.60%us-gaap_DebtWeightedAverageInterestRate
/ us-gaap_DebtInstrumentAxis
= dte_SixPointSixPercentSecuritizationBondsDue2015Member
 
Debt Instrument, Maturity Date Mar. 15, 2015  
Long-term Securitization Bond 105dte_SecuritizationBonds
/ us-gaap_DebtInstrumentAxis
= dte_SixPointSixPercentSecuritizationBondsDue2015Member
302dte_SecuritizationBonds
/ us-gaap_DebtInstrumentAxis
= dte_SixPointSixPercentSecuritizationBondsDue2015Member
Junior Subordinated Debentures [Member] | 6.5% Junior Subordinated Debentures Due 2061 [Member]    
Debt Instrument [Line Items]    
Debt, Weighted Average Interest Rate 6.50%us-gaap_DebtWeightedAverageInterestRate
/ us-gaap_DebtInstrumentAxis
= dte_SixPointFivePercentJuniorSubordinatedDebenturesDue2061Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_JuniorSubordinatedDebtMember
 
Debt Instrument, Maturity Date Dec. 01, 2061  
Junior Subordinated Notes, Noncurrent 280us-gaap_JuniorSubordinatedLongTermNotes
/ us-gaap_DebtInstrumentAxis
= dte_SixPointFivePercentJuniorSubordinatedDebenturesDue2061Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_JuniorSubordinatedDebtMember
280us-gaap_JuniorSubordinatedLongTermNotes
/ us-gaap_DebtInstrumentAxis
= dte_SixPointFivePercentJuniorSubordinatedDebenturesDue2061Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_JuniorSubordinatedDebtMember
Junior Subordinated Debentures [Member] | 5.25% Junior Subordinated Debentures Due 2062 [Member]    
Debt Instrument [Line Items]    
Debt, Weighted Average Interest Rate 5.25%us-gaap_DebtWeightedAverageInterestRate
/ us-gaap_DebtInstrumentAxis
= dte_FivePointTwoFivePercentJuniorSubordinatedDebenturesDue2062Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_JuniorSubordinatedDebtMember
 
Debt Instrument, Maturity Date Dec. 01, 2062  
Junior Subordinated Notes, Noncurrent 200us-gaap_JuniorSubordinatedLongTermNotes
/ us-gaap_DebtInstrumentAxis
= dte_FivePointTwoFivePercentJuniorSubordinatedDebenturesDue2062Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_JuniorSubordinatedDebtMember
200us-gaap_JuniorSubordinatedLongTermNotes
/ us-gaap_DebtInstrumentAxis
= dte_FivePointTwoFivePercentJuniorSubordinatedDebenturesDue2062Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_JuniorSubordinatedDebtMember
DTE Energy [Member] | Unsecured Debt [Member] | 4.6% Unsecured Debt Due 2016 to 2033 [Member]    
Debt Instrument [Line Items]    
Debt, Weighted Average Interest Rate 4.60%us-gaap_DebtWeightedAverageInterestRate
/ us-gaap_DebtInstrumentAxis
= dte_FourPointSixPercentUnsecuredDebtDue2016to2033Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
 
Debt Instrument, Maturity Date Range, Start Jun. 01, 2016  
Debt Instrument, Maturity Date Range, End Apr. 15, 2033  
Long-term Debt, Total 1,647us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= dte_FourPointSixPercentUnsecuredDebtDue2016to2033Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
1,297us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= dte_FourPointSixPercentUnsecuredDebtDue2016to2033Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
DTE Electric [Member] | Secured Debt [Member] | 4.5% Taxable Debt, Principally Secured Due 2016 to 2044 [Member]    
Debt Instrument [Line Items]    
Debt, Weighted Average Interest Rate 4.50%us-gaap_DebtWeightedAverageInterestRate
/ us-gaap_DebtInstrumentAxis
= dte_FourPointFivePercentTaxableDebtPrincipallySecuredDue2016to2044Member
/ dei_LegalEntityAxis
= dte_ElectricMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember
 
Debt Instrument, Maturity Date Range, Start Mar. 31, 2016  
Debt Instrument, Maturity Date Range, End Jun. 01, 2044  
Long-term Debt, Total 4,824us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= dte_FourPointFivePercentTaxableDebtPrincipallySecuredDue2016to2044Member
/ dei_LegalEntityAxis
= dte_ElectricMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember
4,286us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= dte_FourPointFivePercentTaxableDebtPrincipallySecuredDue2016to2044Member
/ dei_LegalEntityAxis
= dte_ElectricMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember
DTE Electric [Member] | Tax Exempt Revenue Bonds [Member] | 5.2% Tax Exempt Revenue Bonds Due 2020 to 2030 [Member]    
Debt Instrument [Line Items]    
Debt, Weighted Average Interest Rate 5.20%us-gaap_DebtWeightedAverageInterestRate
/ us-gaap_DebtInstrumentAxis
= dte_FivePointTwoPercentTaxExemptRevenueBondsDue2020to2030Member
/ dei_LegalEntityAxis
= dte_ElectricMember
/ us-gaap_LongtermDebtTypeAxis
= dte_TaxExemptRevenueBondsMember
 
Debt Instrument, Maturity Date Range, Start Jul. 01, 2020  
Debt Instrument, Maturity Date Range, End Dec. 01, 2030  
Long-term Debt, Total 330us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= dte_FivePointTwoPercentTaxExemptRevenueBondsDue2020to2030Member
/ dei_LegalEntityAxis
= dte_ElectricMember
/ us-gaap_LongtermDebtTypeAxis
= dte_TaxExemptRevenueBondsMember
558us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= dte_FivePointTwoPercentTaxExemptRevenueBondsDue2020to2030Member
/ dei_LegalEntityAxis
= dte_ElectricMember
/ us-gaap_LongtermDebtTypeAxis
= dte_TaxExemptRevenueBondsMember
DTE Gas [Member] | Secured Debt [Member] | 5.2% Taxable Debt, Principally Secured Due 2015 to 2044 [Member]    
Debt Instrument [Line Items]    
Debt, Weighted Average Interest Rate 5.20%us-gaap_DebtWeightedAverageInterestRate
/ us-gaap_DebtInstrumentAxis
= dte_FivePointTwoPercentTaxableDebtPrincipallySecuredDue2015to2044Member
/ dei_LegalEntityAxis
= dte_GasMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember
 
Debt Instrument, Maturity Date Range, Start Sep. 01, 2015  
Debt Instrument, Maturity Date Range, End Dec. 15, 2044  
Long-term Debt, Total 1,099us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= dte_FivePointTwoPercentTaxableDebtPrincipallySecuredDue2015to2044Member
/ dei_LegalEntityAxis
= dte_GasMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember
1,029us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= dte_FivePointTwoPercentTaxableDebtPrincipallySecuredDue2015to2044Member
/ dei_LegalEntityAxis
= dte_GasMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SecuredDebtMember
DTE Gas [Member] | Long Term Debt, Other [Member]    
Debt Instrument [Line Items]    
Long-term Debt, Total $ 121us-gaap_LongTermDebt
/ dei_LegalEntityAxis
= dte_GasMember
/ us-gaap_LongtermDebtTypeAxis
= dte_LongTermDebtOtherMember
$ 142us-gaap_LongTermDebt
/ dei_LegalEntityAxis
= dte_GasMember
/ us-gaap_LongtermDebtTypeAxis
= dte_LongTermDebtOtherMember