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Long-Term Debt (Long Term Debt Outstanding and Weighted Average Interest Rates) (Details) - USD ($)
$ in Millions
Dec. 31, 2017
Dec. 31, 2016
Debt Instrument [Line Items]    
Long-term debt, excluding current maturities $ 11,039 $ 10,506
Long-term debt, total 12,407  
Other long-term debt    
Debt Instrument [Line Items]    
Long-term debt, gross 7 92
Secured debt, unsecured debt, mortgage notes and other debt    
Debt Instrument [Line Items]    
Long-term debt, gross 11,227 10,592
Unamortized debt discount and premium, net (15) (10)
Unamortized debt issuance costs (69) (67)
Long-term debt due within one year (104) (9)
Long-term debt, excluding current maturities $ 11,039 10,506
Junior subordinated debentures    
Debt Instrument [Line Items]    
Interest rate 5.50%  
Long-term debt, gross $ 1,180 780
Unamortized debt issuance costs (35) (24)
Long-term debt, total 1,145 756
DTE Electric    
Debt Instrument [Line Items]    
Long-term debt, gross 6,065 5,925
Long-term debt, excluding current maturities 6,017 5,878
Long-term debt, total $ 6,065  
DTE Electric | Secured debt    
Debt Instrument [Line Items]    
Interest rate 4.30%  
Long-term debt, gross $ 5,755 5,615
DTE Electric | Tax-exempt revenue bonds    
Debt Instrument [Line Items]    
Interest rate 4.30%  
Long-term debt, gross $ 310 310
DTE Electric | Secured debt, unsecured debt, mortgage notes and other debt    
Debt Instrument [Line Items]    
Unamortized debt discount and premium, net (10) (10)
Unamortized debt issuance costs $ (38) (37)
DTE Gas | Secured debt    
Debt Instrument [Line Items]    
Interest rate 4.80%  
Long-term debt, gross $ 1,330 1,250
DTE Energy | Unsecured debt    
Debt Instrument [Line Items]    
Interest rate 3.10%  
Long-term debt, gross $ 3,825 $ 3,325