Significant Accounting Policies (Financing Receivables Classified by Internal Grade of Credit Risk) (Details) $ in Millions	Jun. 30, 2020 USD ($)
Notes receivable
Financing Receivable, Credit Quality Indicator [Line Items]
2020	$ 40
2019	22
2018 and prior	16
Total	78
Notes receivable | Internal grade 1
Financing Receivable, Credit Quality Indicator [Line Items]
2020	2
2019	9
2018 and prior	9
Total	20
Notes receivable | Internal grade 2
Financing Receivable, Credit Quality Indicator [Line Items]
2020	38
2019	13
2018 and prior	7
Total	58
Net investment in leases
Financing Receivable, Credit Quality Indicator [Line Items]
2020	140
2019	0
2018 and prior	43
Total	183
Net investment in leases | Internal grade 1
Financing Receivable, Credit Quality Indicator [Line Items]
2020	8
2019	0
2018 and prior	42
Total	50
Net investment in leases | Internal grade 2
Financing Receivable, Credit Quality Indicator [Line Items]
2020	132
2019	0
2018 and prior	1
Total	133
DTE Electric | Notes receivable
Financing Receivable, Credit Quality Indicator [Line Items]
Total	11
DTE Electric | Notes receivable | Internal grade 1
Financing Receivable, Credit Quality Indicator [Line Items]
Total	11
DTE Electric | Notes receivable | Internal grade 2
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0
DTE Electric | Net investment in leases
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0
DTE Electric | Net investment in leases | Internal grade 1
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0
DTE Electric | Net investment in leases | Internal grade 2
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 0