Retirement Benefits and Trusteed Assets (Other Changes in Plan Assets and Accumulated Postretirement Benefit Obligation) (Details) - Other postretirement benefit plan - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Other changes in plan assets and accumulated postretirement benefit obligation recognized in Regulatory assets and liabilities and Other comprehensive income (loss)
Net actuarial (gain) loss	$ 2	$ (103)
Amortization of net actuarial loss	(2)	(6)
Amortization of prior service credit	0	10
Total recognized in Regulatory assets and liabilities and Other comprehensive income (loss)	0	(99)
Total recognized in net periodic pension credit, Regulatory assets, and Other comprehensive income (loss)	(39)	(143)
DTE Electric
Other changes in plan assets and accumulated postretirement benefit obligation recognized in Regulatory assets and liabilities and Other comprehensive income (loss)
Net actuarial (gain) loss	(1)	(98)
Amortization of net actuarial loss	2	(1)
Amortization of prior service credit	0	6
Total recognized in Regulatory assets and liabilities and Other comprehensive income (loss)	1	(93)
Total recognized in net periodic pension credit, Regulatory assets, and Other comprehensive income (loss)	$ (21)	$ (116)