Retirement Benefits and Trusteed Assets (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	$ 25	$ 21
Interest Cost	53	53
Expected Return on Plan Assets	(74)	(68)
Amortization of Net Actuarial Losses	51	38
Amortization of Prior Service Cost (Credit)	0	0
Net Periodic Benefit Cost (Credit)	55	44
Pension Benefits | DTE Electric
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	20	17
Interest Cost	40	40
Expected Return on Plan Assets	(53)	(48)
Amortization of Net Actuarial Losses	38	27
Amortization of Prior Service Cost (Credit)	0	0
Net Periodic Benefit Cost (Credit)	45	36
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	9	9
Interest Cost	20	23
Expected Return on Plan Assets	(33)	(31)
Amortization of Net Actuarial Losses	11	5
Amortization of Prior Service Cost (Credit)	(31)	(36)
Net Periodic Benefit Cost (Credit)	(24)	(30)
Other Postretirement Benefits | DTE Electric
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	7	7
Interest Cost	16	17
Expected Return on Plan Assets	(23)	(21)
Amortization of Net Actuarial Losses	8	3
Amortization of Prior Service Cost (Credit)	(24)	(27)
Net Periodic Benefit Cost (Credit)	$ (16)	$ (21)