Segment and Geographic Information 2 (Details) - USD ($) $ in Millions		12 Months Ended
		Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Information about Company by geographic area
Total revenue		$ 4,235	$ 4,036	$ 4,025
Property and equipment, net		237	237	242
Total assets		13,060	12,610	11,204
Total liabilities		7,165	6,921	5,826
From Unaffiliated Customers
Information about Company by geographic area
Total revenue		4,235	4,036	4,025
Between Geographic Areas
Information about Company by geographic area
Total revenue		0	0	0
United States
Information about Company by geographic area
Total revenue		3,090	3,005	2,985
Property and equipment, net		94	105	109
Total assets		9,464	9,018	8,185
Total liabilities		5,753	5,502	4,646
United States | From Unaffiliated Customers
Information about Company by geographic area
Total revenue		2,674	2,586	2,585
United States | Between Geographic Areas
Information about Company by geographic area
Total revenue	[1]	416	419	400
EMEA
Information about Company by geographic area
Total revenue	[2]	979	887	903
Property and equipment, net	[2]	106	93	96
Total assets	[2]	2,638	2,736	2,170
Total liabilities	[2]	986	934	728
EMEA | From Unaffiliated Customers
Information about Company by geographic area
Total revenue	[2]	979	887	903
EMEA | Between Geographic Areas
Information about Company by geographic area
Total revenue	[2]	0	0	0
Other
Information about Company by geographic area
Total revenue		582	563	537
Property and equipment, net		37	39	37
Total assets		958	856	849
Total liabilities		426	485	452
Other | From Unaffiliated Customers
Information about Company by geographic area
Total revenue		582	563	537
Other | Between Geographic Areas
Information about Company by geographic area
Total revenue		0	0	0
Eliminations
Information about Company by geographic area
Total revenue		(416)	(419)	(400)
Property and equipment, net		0	0	0
Total assets		0	0	0
Total liabilities		0	0	0
Eliminations | From Unaffiliated Customers
Information about Company by geographic area
Total revenue		0	0	0
Eliminations | Between Geographic Areas
Information about Company by geographic area
Total revenue	[1]	$ (416)	$ (419)	$ (400)

[1] Represents royalties from foreign subsidiaries determined as a percentage of certain amounts invoiced to customers.

[2] Consists of Europe, the Middle East and Africa.