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Long-Term Debt (Details)
Mar. 31, 2019
USD ($)
Debt Instrument [Line Items]  
Debt issued $ 650,000,000
DTE Electric | Mortgage Bonds | May 2018 4.05% Mortgage Bonds Maturing 2048  
Debt Instrument [Line Items]  
Interest rate 3.95%
Debt issued $ 650,000,000