Business Combinations (Narrative) (Details) (USD $)	1 Months Ended	6 Months Ended
	Aug. 31, 2011	Sep. 30, 2011
Business Acquisition [Line Items]
Acquired intangible assets amortization period remaining (in years)		2
Acquired intangible assets amortization period remaining (in years)		14
Number of immaterial businesses acquired		3
Contingent consideration maximum		$ 660,000,000
In-Process Research And Development Projects Acquired [Member] | Popcap [Member]
Business Acquisition [Line Items]
Average WACC	13.00%
Weighted average estimated percentage completion of in-process research and development projects	36.00%
In-process research and development projects	6
Assigned fair value	4,000,000
Estimated costs to complete	2,000,000
Aggregate cost to complete	5,000,000
Minimum [Member] | Popcap [Member]
Business Acquisition [Line Items]
Acquired intangible assets amortization period remaining (in years)	3
Maximum [Member] | Popcap [Member]
Business Acquisition [Line Items]
Acquired intangible assets amortization period remaining (in years)	9
Popcap [Member]
Business Acquisition [Line Items]
Date of purchase agreement	August 2011
Aggregate purchase price in cash	645,000,000
Aggregate purchase price in equity	87,000,000
Contingent consideration maximum		550,000,000
Contingent consideration of fair value	95,000,000	95,000,000
Restricted Stock Unit Awards And Options		50,000,000
Acquired in-process research and development assets	$ 15,000,000