Description Of Business And Basis Of Presentation New revenue standard adoption - Balance Sheet at Period End (Details) - USD ($) $ in Millions	Jun. 30, 2018	Apr. 01, 2018		Mar. 31, 2018		Jun. 30, 2017	Mar. 31, 2017
Condensed Balance Sheet Statements, Captions [Line Items]
Deferred Revenue, Current	$ 602			$ 1,622	[1]
Other liabilities	253			255	[1]
Receivables, Net	371	$ 543		385	[1]
Other current assets	282			288	[1]
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	92	20		84	[1]
Accrued Liabilities, Current	815			821	[1]
Contract with Customer, Liability, Current	129			0
Retained Earnings (Accumulated Deficit)	4,944	4,652		4,062	[1]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(26)	(105)		(127)	[1]	$ (71)	$ (19)
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Other liabilities	(4)
Receivables, Net	129	158	[1]
Other current assets	5
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	(26)	(64)
Contract with Customer, Liability, Current	129
Retained Earnings (Accumulated Deficit)	300	590	[1]
Accumulated Other Comprehensive Income (Loss), Net of Tax	7	22
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Other liabilities	257
Receivables, Net	242
Other current assets	277
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	118
Contract with Customer, Liability, Current	0
Retained Earnings (Accumulated Deficit)	4,644
Accumulated Other Comprehensive Income (Loss), Net of Tax	(33)
Other [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Deferred Revenue, Current	63	105		$ 108
Other [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Deferred Revenue, Current	(26)	(3)
Other [Member] | Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Deferred Revenue, Current	89
Online enabled games [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Deferred Revenue, Current	602	949
Online enabled games [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Deferred Revenue, Current	(298)	$ (673)
Online enabled games [Member] | Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Deferred Revenue, Current	$ 900

[1] Derived from audited Consolidated Financial Statements.