Retirement Benefits and Trusteed Assets (Pension Plan - Reconciliation of Obligations, Assets and Funded Status of Plans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Amounts recognized in Regulatory assets (see Note 8 - Regulatory Matters)
Regulatory Assets	$ 3,724	$ 3,727
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Accumulated benefit obligation, end of year	4,569	4,853
Change in accumulated postretirement benefit obligation
Projected benefit obligation, beginning of year	5,269	4,380
Service cost	100	83	$ 94
Interest cost	210	212	192
Plan amendments	0	(7)
Actuarial (gain) loss	(357)	836
Transfer due to plan sponsorship change	0	0
Special termination benefits	2	0
Benefits paid	(253)	(235)
Projected benefit obligation, end of year	4,971	5,269	4,380
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, beginning of year	3,981	3,720
Actual return on plan assets	(79)	301
Company contributions	183	195
Benefits paid	(253)	(235)
Plan assets at fair value, end of year	3,832	3,981	3,720
Funded status of the plans	(1,139)	(1,288)
Amount recorded as:
Current liabilities	(6)	(8)
Noncurrent liabilities	(1,133)	(1,280)
Defined benefit plans liabilities	(1,139)	(1,288)
Amounts recognized in Accumulated other comprehensive income (loss), pre-tax
Net actuarial loss	180	194
Prior service credit	(1)	(1)
Amounts recognized in Accumulated other comprehensive income (loss), pre-tax	179	193
Amounts recognized in Regulatory assets (see Note 8 - Regulatory Matters)
Net actuarial loss	2,113	2,285
Prior service credit	(1)	(1)
Regulatory Assets	2,112	2,284
Qualified Pension Plan
Change in accumulated postretirement benefit obligation
Service cost	100	83
Interest cost	210	212
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Company contributions	177
DTE Electric
Amounts recognized in Regulatory assets (see Note 8 - Regulatory Matters)
Regulatory Assets	2,986	2,959
DTE Electric | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Accumulated benefit obligation, end of year	3,401	3,712
Change in accumulated postretirement benefit obligation
Projected benefit obligation, beginning of year	4,018	3,341
Service cost	77	64	73
Interest cost	160	162	146
Plan amendments	0	(2)
Actuarial (gain) loss	(273)	634
Transfer due to plan sponsorship change	(99)	0
Special termination benefits	0	0
Benefits paid	(192)	(181)
Projected benefit obligation, end of year	3,685	4,018	3,341
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, beginning of year	2,812	2,632
Actual return on plan assets	(56)	212
Company contributions	145	149
Benefits paid	(192)	(181)
Plan assets at fair value, end of year	2,709	2,812	$ 2,632
Funded status of the plans	(976)	(1,206)
Amount recorded as:
Current liabilities	0	(6)
Noncurrent liabilities	(976)	(1,200)
Defined benefit plans liabilities	(976)	(1,206)
Amounts recognized in Accumulated other comprehensive income (loss), pre-tax
Net actuarial loss	0	44
Prior service credit	0	0
Amounts recognized in Accumulated other comprehensive income (loss), pre-tax	0	44
Amounts recognized in Regulatory assets (see Note 8 - Regulatory Matters)
Net actuarial loss	1,588	1,738
Prior service credit	4	5
Regulatory Assets	1,592	1,743
DTE Electric | Qualified Pension Plan
Change in accumulated postretirement benefit obligation
Service cost	75	64
Interest cost	156	$ 162
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Company contributions	$ 145