Significant Accounting Policies (Roll-Forward of Activity for Financing Receivables Credit Loss Reserves) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 92	$ 104
Current period provision	20	54
Write-offs charged against allowance	(25)	(127)
Recoveries of amounts previously written off	13	61
Ending balance	100	92
DTE Electric
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	54	57
Current period provision	8	36
Write-offs charged against allowance	(18)	(77)
Recoveries of amounts previously written off	9	38
Ending balance	53	54
Trade accounts receivable
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	89	101
Current period provision	20	53
Write-offs charged against allowance	(25)	(126)
Recoveries of amounts previously written off	13	61
Ending balance	97	89
Other receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	3	3
Current period provision	0	1
Write-offs charged against allowance	0	(1)
Recoveries of amounts previously written off	0	0
Ending balance	$ 3	$ 3