RETIREMENT BENEFITS AND TRUSTEED ASSETS

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 September 30,	(In millions)
Service cost	$	22		$	23		$	7		$	7
Interest cost	53			55			18			20
Expected return on plan assets	(78		)	(77		)	(33		)	(33		)
Amortization of:
Net actuarial loss	46			43			3			6
Prior service cost (credit)	1			—			(3		)	(29		)
Net periodic benefit cost (credit)	$	44		$	44		$	(8	)	$	(29	)



	Pension Benefits						Other Postretirement Benefits
	2017			2016			2017			2016
Nine Months Ended September 30,	(In millions)
Service cost	$	69		$	69		$	20		$	20
Interest cost	160			164			55			60
Expected return on plan assets	(233		)	(232		)	(98		)	(97		)
Amortization of:
Net actuarial loss	132			124			10			22
Prior service cost (credit)	1			—			(10		)	(88		)
Net periodic benefit cost (credit)	$	129		$	125		$	(23	)	$	(83	)

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 September 30,	(In millions)
Service cost	$	16		$	18		$	5		$	5
Interest cost	40			42			14			15
Expected return on plan assets	(56		)	(55		)	(23		)	(23		)
Amortization of:
Net actuarial loss	32			31			2			4
Prior service cost (credit)	1			—			(2		)	(22		)
Net periodic benefit cost (credit)	$	33		$	36		$	(4	)	$	(21	)



	Pension Benefits						Other Postretirement Benefits
	2017			2016			2017			2016
Nine Months Ended September 30,	(In millions)
Service cost	$	53		$	53		$	15		$	15
Interest cost	121			125			42			46
Expected return on plan assets	(167		)	(165		)	(68		)	(68		)
Amortization of:
Net actuarial loss	94			88			6			15
Prior service cost (credit)	1			1			(7		)	(66		)
Net periodic benefit cost (credit)	$	102		$	102		$	(12	)	$	(58	)

Pension and Other Postretirement Contributions

During the first nine months of 2017, DTE Energy made cash contributions of $220 million, including contributions from DTE Electric of $185 million, to its pension plans. At the discretion of management and depending upon financial market conditions, DTE Energy may make additional contributions up to $88 million, including additional contributions from DTE Electric of $85 million, to its pension plans in 2017.

DTE Energy does not anticipate making any contributions to the other postretirement benefit plans in 2017.