Retirement Benefits and Trusteed Assets (Reconciliation of Obligations, Assets and Funded Status of Postretirement Plans) (Details) - Other postretirement benefit plan - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Change in accumulated postretirement benefit obligation
Projected/Accumulated postretirement benefit obligation, beginning of year	$ 1,123	$ 1,283
Service cost	15	18	$ 17
Interest cost	61	62	65
Actuarial (gain) loss	24	(165)
Benefits paid	(82)	(75)
Projected/Accumulated postretirement benefit obligation, end of year	1,141	1,123	1,283
Change in plan assets
Plan assets at fair value, beginning of year	1,594	1,614
Actual return on plan assets	139	58
Benefits paid	(79)	(78)
Plan assets at fair value, end of year	1,654	1,594	1,614
Funded status	513	471
Amount recorded as:
Noncurrent assets	761	705
Current liabilities	(1)	(1)
Noncurrent liabilities	(247)	(233)
Defined benefit plans assets (liabilities)	513	471
Amounts recognized in Accumulated other comprehensive income, pre-tax
Net actuarial gain	(13)	(14)
Amounts recognized in Regulatory assets and liabilities
Net actuarial (gain) loss	64	65
DTE Electric
Change in accumulated postretirement benefit obligation
Projected/Accumulated postretirement benefit obligation, beginning of year	849	982
Service cost	11	14	13
Interest cost	46	47	49
Actuarial (gain) loss	15	(139)
Benefits paid	(60)	(55)
Projected/Accumulated postretirement benefit obligation, end of year	861	849	982
Change in plan assets
Plan assets at fair value, beginning of year	1,052	1,070
Actual return on plan assets	92	40
Benefits paid	(57)	(58)
Plan assets at fair value, end of year	1,087	1,052	$ 1,070
Funded status	226	203
Amount recorded as:
Noncurrent assets	463	428
Current liabilities	0	0
Noncurrent liabilities	(237)	(225)
Defined benefit plans assets (liabilities)	226	203
Amounts recognized in Accumulated other comprehensive income, pre-tax
Net actuarial gain	0	0
Amounts recognized in Regulatory assets and liabilities
Net actuarial (gain) loss	$ (25)	$ (26)