Significant Accounting Policies (Financing Receivables Classified by Internal Grade of Credit Risk) (Details) $ in Millions	Mar. 31, 2025 USD ($)
Notes receivable
Financing receivables by year of origination
2025	$ 9
2024	673
2023 and Prior	283
Total	965
Notes receivable | DTE Electric
Financing receivables by year of origination
Total	35
Notes receivable | Internal grade 1
Financing receivables by year of origination
2025	7
2024	4
2023 and Prior	27
Total	38
Notes receivable | Internal grade 1 | DTE Electric
Financing receivables by year of origination
Total	34
Notes receivable | Internal grade 2
Financing receivables by year of origination
2025	2
2024	669
2023 and Prior	256
Total	927
Notes receivable | Internal grade 2 | DTE Electric
Financing receivables by year of origination
Total	1
Net investment in leases
Financing receivables by year of origination
2025	0
2024	2
2023 and Prior	35
Total	37
Net investment in leases | DTE Electric
Financing receivables by year of origination
Total	0
Net investment in leases | Internal grade 1
Financing receivables by year of origination
2025	0
2024	0
2023 and Prior	35
Total	35
Net investment in leases | Internal grade 1 | DTE Electric
Financing receivables by year of origination
Total	0
Net investment in leases | Internal grade 2
Financing receivables by year of origination
2025	0
2024	2
2023 and Prior	0
Total	2
Net investment in leases | Internal grade 2 | DTE Electric
Financing receivables by year of origination
Total	$ 0