Fair Value (Reconciliation of Level 3 Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of December 31	$ (102)	$ 14	$ 19	$ 13
Transfers into Level 3 from Level 2			0	2
Transfers from Level 3 into Level 2	0	(4)	0	2
Total gains (losses)
Included in earnings	80	158	(6)	260
Recorded in Regulatory liabilities	20	(6)	41	20
Purchases, issuances, and settlements
Settlements	(70)	(119)	(126)	(254)
Net Assets (Liabilities) as of September 30	(72)	43	(72)	43
Total gains (losses) included in Net Income attributed to the change in unrealized gains (losses) related to assets and liabilities held at end of period	(48)	56	(82)	16
Total gains (losses) included in Regulatory liabilities attributed to the change in unrealized gains (losses) related to assets and liabilities held at end of period	14	(5)	30	18
Natural gas
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of December 31	19	(9)	27	(18)
Transfers into Level 3 from Level 2			0	2
Transfers from Level 3 into Level 2	0	(4)	0	0
Total gains (losses)
Included in earnings	11	28	(42)	(17)
Recorded in Regulatory liabilities	0	0	0	0
Purchases, issuances, and settlements
Settlements	(12)	4	33	52
Net Assets (Liabilities) as of September 30	18	19	18	19
Total gains (losses) included in Net Income attributed to the change in unrealized gains (losses) related to assets and liabilities held at end of period	0	37	10	13
Total gains (losses) included in Regulatory liabilities attributed to the change in unrealized gains (losses) related to assets and liabilities held at end of period	0	0	0	0
Electricity
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of December 31	(144)	(8)	(19)	24
Transfers into Level 3 from Level 2			0	0
Transfers from Level 3 into Level 2	0	0	0	0
Total gains (losses)
Included in earnings	69	130	29	275
Recorded in Regulatory liabilities	0	0	0	0
Purchases, issuances, and settlements
Settlements	(45)	(117)	(130)	(294)
Net Assets (Liabilities) as of September 30	(120)	5	(120)	5
Total gains (losses) included in Net Income attributed to the change in unrealized gains (losses) related to assets and liabilities held at end of period	(48)	19	(92)	2
Total gains (losses) included in Regulatory liabilities attributed to the change in unrealized gains (losses) related to assets and liabilities held at end of period	0	0	0	0
Other
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of December 31	23	31	11	7
Transfers into Level 3 from Level 2			0	0
Transfers from Level 3 into Level 2	0	0	0	2
Total gains (losses)
Included in earnings	0	0	7	2
Recorded in Regulatory liabilities	20	(6)	41	20
Purchases, issuances, and settlements
Settlements	(13)	(6)	(29)	(12)
Net Assets (Liabilities) as of September 30	30	19	30	19
Total gains (losses) included in Net Income attributed to the change in unrealized gains (losses) related to assets and liabilities held at end of period	0	0	0	1
Total gains (losses) included in Regulatory liabilities attributed to the change in unrealized gains (losses) related to assets and liabilities held at end of period	14	(5)	30	18
DTE Electric
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Net Assets (Liabilities) as of December 31	23	30	11	9
Total gains (losses)
Recorded in Regulatory liabilities	20	(6)	41	20
Purchases, issuances, and settlements
Settlements	(13)	(6)	(22)	(11)
Net Assets (Liabilities) as of September 30	30	18	30	18
Total gains (losses) included in Regulatory liabilities attributed to the change in unrealized gains (losses) related to assets and liabilities held at end of period	$ 14	$ (5)	$ 30	$ 18