Retirement Benefits and Trusteed Assets (Details Textuals) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Transfers into Level 3	$ 0	$ 1,000,000
Transfers out of Level 3	2,000,000	0
Defined contribution plan, cost recognized (less than $1 million in 2012)	48,000,000	41,000,000	37,000,000
Grantor Trust Balance	18,000,000	17,000,000
Retirement Savings Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Company contribution to employee savings plan	4.00%
Retirement Savings Plan [Member] | DTE Gas Represented Employees
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Company contribution to employee savings plan	8.00%
Qualified Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Company contributions	188,000,000
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Company contributions	195,000,000	284,000,000
Expected return on plan assets	7.75%
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.12%	4.95%	4.15%
Pension Plan | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated future employer contributions in next fiscal year	180,000,000
Other Postretirement Benefit Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Company contributions	24,000,000	264,000,000
Expected return on plan assets	8.00%
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Annual allocation to Retiree Reimbursement Account Per Participant, Retired on or before January 1, 2013	3,570	3,500
Annual allocation to Retiree Reimbursement Account Per Participant, Retired after January 1, 2013	3,315	3,250
Retiree Health Care Allowance will increase at lower of the rate of medical inflation or a set percentage	2.00%
Defined Benefit Plan, Effect of One Percentage Point Increase on Service and Interest Cost Components	8,000,000
Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation	108,000,000
Defined Benefit Plan, Effect of One Percentage Point Decrease on Service and Interest Cost Components	7,000,000
Defined Benefit Plan, Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation	94,000,000
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.10%	4.95%	4.15%	4.30%
Other Postretirement Benefit Plan | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated future employer contributions in next fiscal year	200,000,000
Retiree Healthcare Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined contribution plan, cost recognized (less than $1 million in 2012)	$ 4,000,000	$ 2,000,000	$ 1,000,000