Postretirement Benefits

We maintain a number of postretirement benefits, primarily consisting of healthcare and life insurance (“welfare”) benefits, for certain eligible U.S. employees. Eligible employees consist of those who retired before March 31, 1999 and those who retired after March 31, 1999, but were an active employee as of that date, after meeting other age-related criteria. We also provide postretirement benefits for certain U.S. executives. Defined benefit plan obligations are measured as of the Company’s fiscal year-end.

The net periodic expense for our postretirement welfare benefits is as follows:



	Years Ended March 31,
(In millions)	2015			2014			2013
Service cost - benefits earned during the year	$	1		$	2		$	2
Interest cost on accumulated benefit obligation	5			5			6
Amortization of unrecognized actuarial gain and prior service credit	(4		)	(1		)	(2		)
Curtailment gain	—			(2		)	—
Net periodic postretirement expense	$	2		$	4		$	6

Information regarding the changes in benefit obligations for our postretirement welfare plans is as follows:



	Years Ended March 31,
(In millions)	2015			2014
Benefit obligation at beginning of period	$	119		$	131
Service cost	1			2
Interest cost	5			5
Actuarial loss (gain)	5			(2		)
Benefit payments	(12		)	(15		)
Curtailment gain	—			(2		)
Benefit obligation at end of period	$	118		$	119

The components of the amount recognized in accumulated other comprehensive income for the Company’s other postretirement benefits at March 31, 2015 and 2014 were net actuarial losses of $1 million and gains of $8 million and net prior service credits of $1 million and $1 million. Other changes in benefit obligations recognized in other comprehensive income were net actuarial losses of $9 million in 2015 and gains of $2 million and $7 million in 2014 and 2013.

We estimate that the amortization of the actuarial gain from stockholders’ equity to other postretirement expense in 2016 will be $1 million. Comparable 2015 amount was $4 million.

Other postretirement benefits are funded as claims are paid. Expected benefit payments for our postretirement welfare benefit plans are as follows: $10 million annually for 2016 to 2020 and $44 million cumulatively for 2021 through 2025. Expected benefit payments are based on the same assumptions used to measure the benefit obligations and include estimated future employee service. Expected contributions to be made for our postretirement welfare benefit plans are $10 million for 2016.

Weighted-average discount rates used to estimate postretirement welfare benefit expenses were 4.07%, 3.84% and 4.44% for 2015, 2014 and 2013. Weighted-average discount rates for the actuarial present value of benefit obligations were 3.61%, 4.08% and 3.84% for 2015, 2014 and 2013.

Actuarial gain or loss for the postretirement welfare benefit plan is amortized to income or expense over a three-year period. The assumed healthcare cost trends used in measuring the accumulated postretirement benefit obligation were 6.75% and 7.00% for prescription drugs, 7.25/6.75% and 7.50/7.00% for ages pre-65/post-65 medical and 5.00% for dental in 2015 and 2014. For 2015, 2014 and 2013, a one-percentage-point increase or decrease in the assumed healthcare cost trend rate would not have a material impact on the postretirement benefit obligations.

Pursuant to various collective bargaining agreements, we contribute to multiemployer health and welfare plans that cover union-represented employees. Our liability is limited to the contractual dollar obligations set forth by the collective bargaining agreements. Contributions to the plans and amounts accrued were not material for the years ended March 31, 2015, 2014, and 2013.