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
	2018			2017			2018			2017
Three Months Ended September 30,	(In millions)
Service cost	$	24		$	22		$	6		$	7
Interest cost	51			53			18			18
Expected return on plan assets	(82		)	(78		)	(36		)	(33		)
Amortization of:
Net actuarial loss	43			46			3			3
Prior service cost (credit)	—			1			—			(3		)
Net periodic benefit cost (credit)	$	36		$	44		$	(9	)	$	(8	)



	Pension Benefits						Other Postretirement Benefits
	2018			2017			2018			2017
Nine Months Ended September 30,	(In millions)
Service cost	$	74		$	69		$	20		$	20
Interest cost	151			160			52			55
Expected return on plan assets	(247		)	(233		)	(107		)	(98		)
Amortization of:
Net actuarial loss	132			132			8			10
Prior service cost (credit)	—			1			—			(10		)
Net periodic benefit cost (credit)	$	110		$	129		$	(27	)	$	(23	)

DTE Electric participates in various plans that provide pension and other postretirement benefits for DTE Energy and its affiliates. The plans are sponsored by DTE Energy's subsidiary, DTE Energy Corporate Services, LLC. DTE Electric accounts for its participation in DTE Energy's qualified and nonqualified pension plans by applying multiemployer accounting. DTE Electric accounts for its participation in other postretirement benefit plans by applying multiple-employer accounting. Within multiemployer and multiple-employer plans, participants pool plan assets for investment purposes and to reduce the cost of plan administration. The primary difference between plan types is assets contributed in multiemployer plans can be used to provide benefits for all participating employers, while assets contributed within a multiple-employer plan are restricted for use by the contributing employer. As a result of multiemployer accounting treatment, capitalized costs associated with these plans are reflected in Property, plant, and equipment in DTE Electric's Consolidated Financial Statements. The same capitalized costs are reflected as Regulatory assets and liabilities in DTE Energy's Consolidated Financial Statements. Plan participants of all plans are solely DTE Energy and affiliate participants.

DTE Energy's subsidiaries are responsible for their share of qualified and nonqualified pension benefit costs. DTE Electric's allocated portion of pension benefit costs included in capital expenditures and operating and maintenance expense were $30 million and $33 million for the three months ended September 30, 2018 and 2017, respectively, and $90 million and $102 million for the nine months ended September 30, 2018 and 2017, respectively. These amounts include recognized contractual termination benefit charges, curtailment gains, and settlement charges.

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 September 30,	(In millions)
Service cost	$	5		$	5
Interest cost	13			14
Expected return on plan assets	(25		)	(23		)
Amortization of:
Net actuarial loss	3			2
Prior service credit	—			(2		)
Net periodic benefit credit	$	(4	)	$	(4	)



	Other Postretirement Benefits
	2018			2017
Nine Months Ended September 30,	(In millions)
Service cost	$	15		$	15
Interest cost	40			42
Expected return on plan assets	(74		)	(68		)
Amortization of:
Net actuarial loss	7			6
Prior service credit	—			(7		)
Net periodic benefit credit	$	(12	)	$	(12	)

Pension and Other Postretirement Contributions

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

The above contribution was made on behalf of DTE Electric, who paid DTE Energy cash consideration of $175 million in March 2018. DTE Energy does not anticipate making any additional contributions to its pension or other postretirement benefit plans in 2018.