Retirement Benefits and Trusteed Assets (OPEB - Benefits related to Qualified and Nonqualified Pension Plans Expected to be paid in the Next Ten Years) (Details) - Other Postretirement Benefit Plan $ in Millions	Dec. 31, 2015 USD ($)
Defined Benefit Plan Disclosure [Line Items]
2016	$ 100
2017	105
2018	108
2019	113
2020	116
2021-2025	621
Total Expected Future Benefit Payments	1,163
DTE Electric
Defined Benefit Plan Disclosure [Line Items]
2016	77
2017	81
2018	84
2019	88
2020	90
2021-2025	476
Total Expected Future Benefit Payments	$ 896