Income Taxes (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Jan. 18, 2011
Operating Loss Carryforwards [Line Items]
Effective tax rates	6.20%	6.30%	5.50%	0.20%
United States statutory tax rate	35.00%		35.00%
Reduction in income tax expense	$ 12	$ 19	$ (19)	$ (1)
Recorded increase in gross unrecognized tax benefits	5		13
Gross unrecognized tax benefits	286		286
Amount of unrecognized tax benefits that would affect the effective tax rate	144		144
The total amount of unrecognized tax benefits that, if recognized, would result in adjustments to deferred tax assets with corresponding adjustments to the valuation allowance	130		130
Decrease in accrued interest and penalties related to uncertain tax positions	2
Combined amount of accrued interest and penalties related to uncertain tax positions	22		22
Incremental tax liability asserted by jurisdiction					44
Effective tax rate for non-U.S. profits	0.00%
PopCap And KlickNation [Member]
Operating Loss Carryforwards [Line Items]
Net deferred tax liabilities	3		58
Tax Authority Deposit [Member]
Operating Loss Carryforwards [Line Items]
Deposits	43		43
Valuation Allowance Release [Member] | PopCap [Member]
Operating Loss Carryforwards [Line Items]
Reduction in income tax expense	3		58
Maximum [Member]
Operating Loss Carryforwards [Line Items]
Amount of unrecognized tax benefits for which it is reasonably possible that there will be a reduction within the next 12 months	$ 55		$ 55