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Long-Term Debt (Debt Issuances) (Details) (USD $)
In Millions, unless otherwise specified
Dec. 31, 2014
Debt Instrument [Line Items]  
Debt face amount $ 1,750us-gaap_DebtInstrumentFaceAmount
DTE Energy [Member] | Senior Notes [Member] | May 2014 3.50% Senior Notes Maturing in 2024 [Member]  
Debt Instrument [Line Items]  
Debt instrument stated interest rate 3.50%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= dte_May20143.50SeniorNotesMaturingin2024Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
Debt face amount 350us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= dte_May20143.50SeniorNotesMaturingin2024Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
DTE Energy [Member] | Senior Notes [Member] | November 2014 2.40% Senior Notes Maturing in 2019 [Member]  
Debt Instrument [Line Items]  
Debt instrument stated interest rate 2.40%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= dte_November20142.40SeniorNotesMaturingin2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
Debt face amount 300us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= dte_November20142.40SeniorNotesMaturingin2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
Electric [Member] | Mortgages [Member] | June 2014 3.77% Mortgage Bonds Maturing in 2026 [Member]  
Debt Instrument [Line Items]  
Debt instrument stated interest rate 3.77%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= dte_June20143.77MortgageBondsMaturingin2026Member
/ dei_LegalEntityAxis
= dte_ElectricMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_MortgagesMember
Debt face amount 100us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= dte_June20143.77MortgageBondsMaturingin2026Member
/ dei_LegalEntityAxis
= dte_ElectricMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_MortgagesMember
Electric [Member] | Mortgages [Member] | June 2014 4.60% Mortgage Bonds Maturing in 2044 [Member]  
Debt Instrument [Line Items]  
Debt instrument stated interest rate 4.60%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= dte_June20144.60MortgageBondsMaturingin2044Member
/ dei_LegalEntityAxis
= dte_ElectricMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_MortgagesMember
Debt face amount 150us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= dte_June20144.60MortgageBondsMaturingin2044Member
/ dei_LegalEntityAxis
= dte_ElectricMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_MortgagesMember
Electric [Member] | Mortgages [Member] | July 2014 3.375% Mortgage Bonds Maturing in 2025 [Member]  
Debt Instrument [Line Items]  
Debt instrument stated interest rate 3.375%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= dte_July20143.375MortgageBondsMaturingin2025Member
/ dei_LegalEntityAxis
= dte_ElectricMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_MortgagesMember
Debt face amount 350us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= dte_July20143.375MortgageBondsMaturingin2025Member
/ dei_LegalEntityAxis
= dte_ElectricMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_MortgagesMember
Electric [Member] | Mortgages [Member] | July 2014 4.30% Mortgage Bonds Maturing in 2044 [Member]  
Debt Instrument [Line Items]  
Debt instrument stated interest rate 4.30%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= dte_July20144.30MortgageBondsMaturingin2044Member
/ dei_LegalEntityAxis
= dte_ElectricMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_MortgagesMember
Debt face amount 350us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= dte_July20144.30MortgageBondsMaturingin2044Member
/ dei_LegalEntityAxis
= dte_ElectricMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_MortgagesMember
Gas [Member] | Mortgages [Member] | December 2014 4.35% Mortgage Bonds Maturing in 2044 [Member]  
Debt Instrument [Line Items]  
Debt instrument stated interest rate 4.35%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= dte_December20144.35MortgageBondsMaturingin2044Member
/ dei_LegalEntityAxis
= dte_GasMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_MortgagesMember
Debt face amount $ 150us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= dte_December20144.35MortgageBondsMaturingin2044Member
/ dei_LegalEntityAxis
= dte_GasMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_MortgagesMember