Significant Accounting Policies (Financing Receivables Classified by Internal Grade of Credit Risk) (Details) $ in Millions	Mar. 31, 2022 USD ($)
Notes receivable
Financing Receivable, Credit Quality Indicator [Line Items]
2022	$ 1
2021	16
2020 and Prior	110
Total	127
Notes receivable | DTE Electric
Financing Receivable, Credit Quality Indicator [Line Items]
Total	17
Notes receivable | Internal grade 1
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020 and Prior	19
Total	19
Notes receivable | Internal grade 1 | DTE Electric
Financing Receivable, Credit Quality Indicator [Line Items]
Total	14
Notes receivable | Internal grade 2
Financing Receivable, Credit Quality Indicator [Line Items]
2022	1
2021	16
2020 and Prior	91
Total	108
Notes receivable | Internal grade 2 | DTE Electric
Financing Receivable, Credit Quality Indicator [Line Items]
Total	3
Net investment in leases
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020 and Prior	229
Total	229
Net investment in leases | DTE Electric
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0
Net investment in leases | Internal grade 1
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020 and Prior	38
Total	38
Net investment in leases | Internal grade 1 | DTE Electric
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0
Net investment in leases | Internal grade 2
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020 and Prior	191
Total	191
Net investment in leases | Internal grade 2 | DTE Electric
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 0