Significant Accounting Policies (Schedule of Other Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule of Other Nonoperating Income, by Component [Line Items]
Income from REF entities	$ 141	$ 139	$ 130
Equity in earnings of equity method investees	38	26	14
Contract services	27	28	29
Allowance for equity funds used during construction	27	25	24
Gains from rabbi trust securities	8	28	37
Other	13	13	16
Other income	254	259	250
DTE Electric
Schedule of Other Nonoperating Income, by Component [Line Items]
Contract services	27	28	32
Allowance for equity funds used during construction	25	23	22
Gains from rabbi trust securities	8	28	37
Other	11	8	16
Other income	$ 71	$ 87	$ 107