Segment Information (Net Revenue By Platform) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net Revenue by Platform [Line Items]
Net revenue	$ 1,286	$ 959	$ 2,423	$ 2,408
Total consoles
Net Revenue by Platform [Line Items]
Net revenue	917	595	1,622	1,629
PC and Browsers, net revenue
Net Revenue by Platform [Line Items]
Net revenue	149	196	346	436
Mobile, net revenue
Net Revenue by Platform [Line Items]
Net revenue	220	162	453	333
Other, net revenue
Net Revenue by Platform [Line Items]
Net revenue	$ 0	$ 6	$ 2	$ 10