Long-Term Debt (Debt Issuances) (Details)	Dec. 31, 2018 USD ($)
Debt Instrument [Line Items]
Amount	$ 1,445,000,000
DTE Energy | Senior Notes | August 2018 3.70% Senior Notes Maturing 2023
Debt Instrument [Line Items]
Interest Rate	3.70%
Amount	$ 600,000,000
DTE Electric | Mortgage Bonds | May 2018 4.05% Mortgage Bonds Maturing 2048
Debt Instrument [Line Items]
Interest Rate	4.05%
Amount	$ 525,000,000
DTE Gas | Mortgage Bonds | August 2018 3.81% Mortgage Bonds Maturing 2028
Debt Instrument [Line Items]
Interest Rate	3.81%
Amount	$ 195,000,000
DTE Gas | Mortgage Bonds | August 2018 4.14% Mortgage Bonds Maturing 2048
Debt Instrument [Line Items]
Interest Rate	4.14%
Amount	$ 125,000,000