Segment Information (Net Revenue By Timing Recognition) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting, Revenue Reconciling Item
Net revenue	$ 1,673	$ 1,593	$ 4,283	$ 4,150
Recognized at a point in time
Segment Reporting, Revenue Reconciling Item
Net revenue	860	772	1,639	1,649
Recognized over time
Segment Reporting, Revenue Reconciling Item
Net revenue	$ 813	$ 821	$ 2,644	$ 2,501