Postretirement Benefits (Tables)

12 Months Ended

Mar. 31, 2018

Defined Benefit Plan [Abstract]

Schedule of net periodic (credit) expense for postretirement welfare benefits

The net periodic expense for our pension plans is as follows:

	U.S. Plans									Non-U.S. Plans
	Years Ended March 31,									Years Ended March 31,
(In millions)	2018			2017			2016			2018			2017			2016
Service cost - benefits earned during the year	$	3		$	5		$	4		$	15		$	15		$	20
Interest cost on projected benefit obligation	14			13			18			22			23			24
Expected return on assets	(19		)	(15		)	(19		)	(26		)	(26		)	(30		)
Amortization of unrecognized actuarial loss and prior service costs	6			11			42			5			4			3
Curtailment/settlement loss (gain)	2			—			2			1			(2		)	—
Net periodic pension expense	$	6		$	14		$	47		$	17		$	14		$	17

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

	Years Ended March 31,
(In millions)	2018			2017			2016
Service cost - benefits earned during the year	$	1		$	1		$	1
Interest cost on accumulated benefit obligation	2			2			4
Amortization of unrecognized actuarial gain and prior service credit	(6		)	(1		)	—
Net periodic postretirement (credit) expense	$	(3	)	$	2		$	5

Schedule of changes in benefit obligations for postretirement welfare plans

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

	Years Ended March 31,
(In millions)	2018			2017
Benefit obligation at beginning of period	$	82		$	98
Service cost	1			1
Interest cost	2			2
Actuarial gain	(1		)	(13		)
Benefit payments	(6		)	(6		)
Benefit obligation at end of period	$	78		$	82