Significant Accounting Policies (Other Income) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Schedule of Other Nonoperating Income, by Component [Line Items]
Allowance for equity funds used during construction	$ 37	$ 26	$ 107	$ 72
Contract services	15	11	44	31
Equity earnings of equity method investees	5	5	12	16
Investment income	1	8	11	16
Other	6	4	15	12
Total other income	64	54	189	147
DTE Electric
Schedule of Other Nonoperating Income, by Component [Line Items]
Allowance for equity funds used during construction	36	25	104	71
Contract services	15	11	44	31
Investment income	1	5	10	12
Other	3	4	10	9
Total other income	$ 55	$ 45	$ 168	$ 123