Retirement Benefits and Trusteed Assets (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 23	$ 25
Interest cost	54	53
Expected return on plan assets	(77)	(74)
Amortization of net actuarial loss	40	51
Amortization of prior service credit	0	0
Net periodic benefit cost (credit)	40	55
Pension Benefits | DTE Electric
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	18	20
Interest cost	41	40
Expected return on plan assets	(55)	(53)
Amortization of net actuarial loss	29	38
Amortization of prior service credit	0	0
Net periodic benefit cost (credit)	33	45
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	6	9
Interest cost	20	20
Expected return on plan assets	(32)	(33)
Amortization of net actuarial loss	8	11
Amortization of prior service credit	(30)	(31)
Net periodic benefit cost (credit)	(28)	(24)
Other Postretirement Benefits | DTE Electric
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	5	7
Interest cost	15	16
Expected return on plan assets	(23)	(23)
Amortization of net actuarial loss	6	8
Amortization of prior service credit	(22)	(24)
Net periodic benefit cost (credit)	$ (19)	$ (16)