Significant Accounting Policies (Other Income) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Schedule of Other Nonoperating Income, by Component [Line Items]
Allowance for equity funds used during construction	$ 8	$ 7
Contract services	7	8
Income from REF entities	0	24
Gains from rabbi trust securities	0	2
Equity earnings (losses) of equity method investees	(11)	1
Other	4	1
Total other income	8	43
DTE Electric
Schedule of Other Nonoperating Income, by Component [Line Items]
Allowance for equity funds used during construction	7	6
Contract services	7	8
Gains from rabbi trust securities	0	2
Other	2	3
Total other income	$ 16	$ 19