Income Taxes - Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Mar. 31, 2018
Deferred tax assets:
Loss carryovers	$ 91	$ 0
Employee benefits	54	1
Accrued liabilities	22	8
Capital lease obligations	16	41
Interest expense carryforward	11	0
Deferred service revenue	2	16
Restructuring	1	2
Other	1	0
Deferred tax assets, gross	198	68
Valuation allowance	(13)	0
Deferred tax assets, net of valuation allowance	185	68
Deferred tax liabilities:
Purchased intangible assets	312	224
Fixed assets	30	12
Deferred service cost	1	4
Other receivables	0	(4)
Deferred tax liabilities	343	244
Total deferred tax liabilities	$ (158)	$ (176)