Significant Accounting Policies (Effective Income Tax Rate Reconciliation) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Schedule of Income Taxes [Line Items]
Statutory federal income tax rate	21.00%	21.00%	21.00%	21.00%
Increase (decrease) due to:
State and local income taxes, net of federal benefit	3.90%	4.20%	4.60%	4.20%
Investment tax credits	(25.20%)	(13.20%)	(26.30%)	(13.50%)
Production tax credits	(20.60%)	(10.80%)	(18.70%)	(10.60%)
TCJA regulatory liability amortization	(5.20%)	(4.70%)	(5.60%)	(4.60%)
AFUDC equity	(2.10%)	(1.40%)	(2.50%)	(1.50%)
Nondeductible EES Coke penalty	0.00%	0.00%	2.30%	0.00%
Valuation allowance due to enactment of federal income tax legislation	0.00%	4.00%	0.00%	1.60%
Enactment of Illinois income tax legislation, net of federal benefit	0.00%	0.00%	0.00%	1.30%
Other	(1.30%)	(0.40%)	(0.80%)	0.00%
Effective income tax rate	(29.50%)	(1.30%)	(26.00%)	(2.10%)
DTE Electric
Schedule of Income Taxes [Line Items]
Statutory federal income tax rate	21.00%	21.00%	21.00%	21.00%
Increase (decrease) due to:
State and local income taxes, net of federal benefit	5.70%	5.60%	5.60%	5.60%
Investment tax credits	(18.70%)	(15.60%)	(19.30%)	(15.90%)
Production tax credits	(6.70%)	(6.60%)	(6.50%)	(6.70%)
TCJA regulatory liability amortization	(4.10%)	(4.60%)	(4.10%)	(4.60%)
AFUDC equity	(2.00%)	(1.80%)	(2.20%)	(1.90%)
Other	(1.80%)	(0.80%)	(1.00%)	(0.50%)
Effective income tax rate	(6.60%)	(2.80%)	(6.50%)	(3.00%)