Segment Information (Net Revenue By Platform) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Net Revenue by Platform [Line Items]
Net revenue	$ 1,593	$ 1,289	$ 4,150	$ 3,712
Console
Net Revenue by Platform [Line Items]
Net revenue	1,163	885	2,846	2,507
PC / Browser
Net Revenue by Platform [Line Items]
Net revenue	257	217	748	563
Mobile
Net Revenue by Platform [Line Items]
Net revenue	169	181	542	634
Other
Net Revenue by Platform [Line Items]
Net revenue	$ 4	$ 6	$ 14	$ 8