Retirement Benefits and Trusteed Assets (OPEB - Reconciliation of Obligations, Assets and Funded Status of Plans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Amounts recognized in Regulatory assets
Regulatory assets	$ 4,176	$ 4,721
Other postretirement benefit plan
Change in accumulated postretirement benefit obligation
Projected/Accumulated postretirement benefit obligation, beginning of year	1,645	1,910
Service cost	22	27	$ 27
Interest cost	70	69	73
Plan amendments	(53)	(44)
Actuarial (gain) loss	153	(227)
Benefits paid	(86)	(90)
Projected/Accumulated postretirement benefit obligation, end of year	1,751	1,645	1,910
Change in plan assets
Plan assets at fair value, beginning of year	1,689	1,848
Actual return on plan assets	215	(75)
Benefits paid	(85)	(84)
Plan assets at fair value, end of year	1,819	1,689	1,848
Funded status	68	44
Amount recorded as:
Noncurrent assets	69	45
Current liabilities	(1)	(1)
Noncurrent liabilities	0	0
Defined benefit plans assets (liabilities)	68	44
Amounts recognized in Accumulated other comprehensive income (loss), pre-tax
Net actuarial (gain) loss	(8)	1
Amounts recognized in Accumulated other comprehensive income (loss), pre-tax	(8)	1
Amounts recognized in Regulatory assets
Net actuarial loss	289	257
Prior service credit	(88)	(44)
Regulatory assets	201	213
DTE Electric
Amounts recognized in Regulatory assets
Regulatory assets	3,453	3,977
DTE Electric | Other postretirement benefit plan
Change in accumulated postretirement benefit obligation
Projected/Accumulated postretirement benefit obligation, beginning of year	1,247	1,470
Service cost	16	20	20
Interest cost	53	53	56
Plan amendments	(33)	(35)
Actuarial (gain) loss	118	(196)
Benefits paid	(64)	(65)
Projected/Accumulated postretirement benefit obligation, end of year	1,337	1,247	1,470
Change in plan assets
Plan assets at fair value, beginning of year	1,158	1,272
Actual return on plan assets	141	(52)
Benefits paid	(63)	(62)
Plan assets at fair value, end of year	1,236	1,158	$ 1,272
Funded status	(101)	(89)
Amount recorded as:
Noncurrent assets	266	189
Current liabilities	0	0
Noncurrent liabilities	(367)	(278)
Defined benefit plans assets (liabilities)	(101)	(89)
Amounts recognized in Accumulated other comprehensive income (loss), pre-tax
Net actuarial (gain) loss	0	0
Amounts recognized in Accumulated other comprehensive income (loss), pre-tax	0	0
Amounts recognized in Regulatory assets
Net actuarial loss	193	156
Prior service credit	(62)	(35)
Regulatory assets	$ 131	$ 121