Significant Accounting Policies (Roll-Forward of Activity for Financing Receivables Credit Loss Reserves) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2020 USD ($)
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 91
Current period provision	56
Write-offs charged against allowance	(91)
Recoveries of amounts previously written off	28
Ending balance	84
Trade accounts receivable
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	87
Current period provision	54
Write-offs charged against allowance	(89)
Recoveries of amounts previously written off	29
Ending balance	81
Other receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	4
Current period provision	2
Write-offs charged against allowance	(2)
Recoveries of amounts previously written off	(1)
Ending balance	3
DTE Electric
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	46
Current period provision	32
Write-offs charged against allowance	(51)
Recoveries of amounts previously written off	17
Ending balance	$ 44