Financial and Other Derivative Instruments (Effect of Derivatives Not Designated as Hedging Instruments) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Derivative Instruments, Gain (Loss) [Line Items]
Total	$ 70	$ 130	$ 122	$ 247
Natural gas | Income Statement Location [Axis]: us-gaap:UnregulatedOperatingRevenue
Derivative Instruments, Gain (Loss) [Line Items]
Total	5	(18)	(261)	66
Natural gas | Income Statement Location [Axis]: dte:UnregulatedOperatingExpenseProductsAndServices
Derivative Instruments, Gain (Loss) [Line Items]
Total	(12)	48	43	(98)
Electricity | Income Statement Location [Axis]: us-gaap:UnregulatedOperatingRevenue
Derivative Instruments, Gain (Loss) [Line Items]
Total	74	90	322	246
Environmental & Other | Income Statement Location [Axis]: us-gaap:UnregulatedOperatingRevenue
Derivative Instruments, Gain (Loss) [Line Items]
Total	2	11	17	34
Foreign currency exchange contracts | Income Statement Location [Axis]: us-gaap:UnregulatedOperatingRevenue
Derivative Instruments, Gain (Loss) [Line Items]
Total	$ 1	$ (1)	$ 1	$ (1)