Retirement Benefits and Trusteed Assets (Tables)

6 Months Ended

Jun. 30, 2018

Defined Benefit Plan [Abstract]

Schedule of Net Periodic Benefit Costs (Credits)

The following tables detail the components of net periodic benefit costs (credits) for other postretirement benefits for DTE Electric:

	Other Postretirement Benefits
	2018			2017
Three Months Ended June 30,	(In millions)
Service cost	$	5		$	5
Interest cost	14			14
Expected return on plan assets	(25		)	(22		)
Amortization of:
Net actuarial loss	2			2
Prior service credit	—			(3		)
Net periodic benefit credit	$	(4	)	$	(4	)

	Other Postretirement Benefits
	2018			2017
Six Months Ended June 30,	(In millions)
Service cost	$	10		$	10
Interest cost	27			28
Expected return on plan assets	(49		)	(45		)
Amortization of:
Net actuarial loss	4			4
Prior service credit	—			(5		)
Net periodic benefit credit	$	(8	)	$	(8	)

The following tables detail the components of net periodic benefit costs (credits) for pension benefits and other postretirement benefits for DTE Energy:

	Pension Benefits						Other Postretirement Benefits
	2018			2017			2018			2017
Three Months Ended June 30,	(In millions)
Service cost	$	25		$	23		$	7		$	6
Interest cost	50			53			17			19
Expected return on plan assets	(83		)	(77		)	(35		)	(32		)
Amortization of:
Net actuarial loss	45			43			2			4
Prior service credit	—			—			—			(4		)
Net periodic benefit cost (credit)	$	37		$	42		$	(9	)	$	(7	)

	Pension Benefits						Other Postretirement Benefits
	2018			2017			2018			2017
Six Months Ended June 30,	(In millions)
Service cost	$	50		$	47		$	14		$	13
Interest cost	100			107			34			37
Expected return on plan assets	(165		)	(155		)	(71		)	(65		)
Amortization of:
Net actuarial loss	89			86			5			7
Prior service credit	—			—			—			(7		)
Net periodic benefit cost (credit)	$	74		$	85		$	(18	)	$	(15	)

Schedule of Defined Benefit Plans Disclosures

During 2018, DTE Energy contributed the following amounts of DTE Energy common stock to the DTE Energy Company Affiliates Employee Benefit Plans Master Trust:

Date	Number of Shares	Price per Share	Amount
			(In millions)
March 7, 2018	1,751,401	$99.92	$	175