Retirement Benefits and Trusteed Assets (Tables)

6 Months Ended

Jun. 30, 2017

Defined Benefit Plan [Abstract]

Schedule of Net Periodic Benefit Costs (Credits)

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
	2017			2016			2017			2016
Three Months Ended June 30,	(In millions)
Service cost	$	23		$	23		$	6		$	7
Interest cost	53			55			19			20
Expected return on plan assets	(77		)	(78		)	(32		)	(32		)
Amortization of:
Net actuarial loss	43			41			4			8
Prior service credit	—			—			(4		)	(29		)
Net periodic benefit cost (credit)	$	42		$	41		$	(7	)	$	(26	)

	Pension Benefits						Other Postretirement Benefits
	2017			2016			2017			2016
Six Months Ended June 30,	(In millions)
Service cost	$	47		$	46		$	13		$	13
Interest cost	107			109			37			40
Expected return on plan assets	(155		)	(155		)	(65		)	(64		)
Amortization of:
Net actuarial loss	86			81			7			16
Prior service credit	—			—			(7		)	(59		)
Net periodic benefit cost (credit)	$	85		$	81		$	(15	)	$	(54	)

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

	Pension Benefits						Other Postretirement Benefits
	2017			2016			2017			2016
Three Months Ended June 30,	(In millions)
Service cost	$	19		$	17		$	5		$	5
Interest cost	40			42			14			16
Expected return on plan assets	(56		)	(55		)	(22		)	(22		)
Amortization of:
Net actuarial loss	31			28			2			5
Prior service cost (credit)	—			1			(3		)	(22		)
Net periodic benefit cost (credit)	$	34		$	33		$	(4	)	$	(18	)

	Pension Benefits						Other Postretirement Benefits
	2017			2016			2017			2016
Six Months Ended June 30,	(In millions)
Service cost	$	37		$	35		$	10		$	10
Interest cost	81			83			28			31
Expected return on plan assets	(111		)	(110		)	(45		)	(45		)
Amortization of:
Net actuarial loss	62			57			4			11
Prior service cost (credit)	—			1			(5		)	(44		)
Net periodic benefit cost (credit)	$	69		$	66		$	(8	)	$	(37	)