Retirement Benefits and Trusteed Assets (Details Textuals) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Maximum contribution amount		$ 25,000,000		$ 25,000,000
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Maximum contribution amount		0		0
DTE Electric | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension cost	$ 175,000,000	30,000,000	$ 34,000,000	60,000,000	$ 69,000,000
Maximum contribution amount		$ 0		$ 0