Retirement Benefits and Trusteed Assets (Details Textuals) - USD ($) $ in Millions	3 Months Ended			9 Months Ended		12 Months Ended
	Dec. 31, 2026	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025	Dec. 31, 2025
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Pension cost (credit)		$ 18	$ 14	$ 53	$ 45
Contributions by employer				0
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension cost (credit)		(10)	(10)	(32)	(30)
Contributions by employer				0
DTE Electric | Pension plans
Defined Benefit Plan Disclosure [Line Items]
Pension cost (credit)		15	12	45	39
Pension funds transferred to (from) plan (up to)						$ 25
DTE Electric | Pension plans | Forecast
Defined Benefit Plan Disclosure [Line Items]
Pension funds transferred to (from) plan (up to)	$ 25
DTE Electric | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension cost (credit)		$ (6)	$ (8)	$ (19)	$ (18)
DTE Gas | Pension plans
Defined Benefit Plan Disclosure [Line Items]
Pension funds transferred to (from) plan (up to)						$ (25)
DTE Gas | Pension plans | Forecast
Defined Benefit Plan Disclosure [Line Items]
Pension funds transferred to (from) plan (up to)	$ (25)