Pension Benefits - Net Periodic Expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost - benefits earned during the year	$ 2	$ 0	$ 2	$ 1
Interest cost on projected benefit obligation	4	4	9	9
Expected return on assets	(4)	(5)	(9)	(11)
Amortization of unrecognized actuarial loss and prior service costs	12	6	21	10
Net periodic pension expense	14	5	23	9
Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost - benefits earned during the year	5	5	10	9
Interest cost on projected benefit obligation	6	9	12	18
Expected return on assets	(8)	(8)	(16)	(15)
Amortization of unrecognized actuarial loss and prior service costs	1	1	2	2
Net periodic pension expense	$ 4	$ 7	$ 8	$ 14