Retirement Benefits and Trusteed Assets (Net Periodic Benefit Costs (Credits)) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 13	$ 12
Interest cost	53	54
Expected return on plan assets	(72)	(73)
Net actuarial (gain) loss	24	22
Net periodic benefit cost (credit)	18	15
Pension Benefits | DTE Electric
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost (credit)	15	14
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	4
Interest cost	15	15
Expected return on plan assets	(30)	(29)
Net actuarial (gain) loss	0	0
Net periodic benefit cost (credit)	(11)	(10)
Other Postretirement Benefits | DTE Electric
Defined Benefit Plan Disclosure [Line Items]
Service cost	3	3
Interest cost	11	12
Expected return on plan assets	(20)	(19)
Net actuarial (gain) loss	(1)	(1)
Net periodic benefit cost (credit)	$ (7)	$ (5)