Significant Accounting Policies (Schedule of Other Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule of Other Nonoperating Income, by Component [Line Items]
Income from REF entities	$ 130	$ 98	$ 77
Equity in earnings of equity method investees	111	132	102
Gains from equity securities	37	6	26
Contract services	29	51	19
Allowance for equity funds used during construction	24	28	23
Other	19	18	21
Other income	350	333	268
DTE Electric
Schedule of Other Nonoperating Income, by Component [Line Items]
Gains from equity securities	37	6	26
Contract services	32	51	21
Allowance for equity funds used during construction	22	19	18
Other	16	7	12
Other income	$ 107	$ 83	$ 77