Long-Term Financings (Debt Issuances) (Details) $ in Millions	Sep. 30, 2026 USD ($)
Mortgages | DTE Electric
Debt Instrument [Line Items]
Amount	$ 2,900
Mortgages | February 2026 4.85% Mortgage Bonds Maturing In 2036 | DTE Electric
Debt Instrument [Line Items]
Interest Rate	4.85%
Amount	$ 800
Mortgages | February 2026 5.55% Mortgage Bonds Maturing In 2056 | DTE Electric
Debt Instrument [Line Items]
Interest Rate	5.55%
Amount	$ 800
Mortgages | September 2026 5.34% Mortgage Bonds Maturing In 2031 | DTE Gas
Debt Instrument [Line Items]
Interest Rate	5.34%
Amount	$ 150
Mortgages | September 2026 5.68% Mortgage Bonds Maturing In 2036 | DTE Gas
Debt Instrument [Line Items]
Interest Rate	5.68%
Amount	$ 100
Mortgages | September 2026 6.26% Mortgage Bonds Maturing In 2056 | DTE Gas
Debt Instrument [Line Items]
Interest Rate	6.26%
Amount	$ 50
Junior Subordinated Debentures
Debt Instrument [Line Items]
Interest Rate	6.20%
Amount	$ 1,000