Segment Information (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Revenue, Major Customer [Line Items]
Net revenue did not exceed ten percent	10.00%
United States [Member]
Revenue, Major Customer [Line Items]
Entity Wide Disclosure On Geographic Areas Revenue From External Customers, Percentage of North America	99.00%
Switzerland [Member]
Revenue, Major Customer [Line Items]
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries	$ 885	$ 589
EntityWideDisclosureOnGeographicAreasRevenueFromExternalCustomersAttributedToForeignCountriesPercentage	23.00%	14.00%
Net revenue did not exceed ten percent			10.00%
United Kingdom [Member]
Revenue, Major Customer [Line Items]
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries			411
EntityWideDisclosureOnGeographicAreasRevenueFromExternalCustomersAttributedToForeignCountriesPercentage			11.00%
Net revenue did not exceed ten percent	10.00%	10.00%
GameStop Corp [Member] | Sales Revenue, Goods, Net [Member] | Customer Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Percent of net revenue by major customer	13.00%	15.00%	16.00%
Wal-Mart Stores, Inc [Member]
Revenue, Major Customer [Line Items]
Net revenue did not exceed ten percent		10.00%
Wal-Mart Stores, Inc [Member] | Sales Revenue, Goods, Net [Member] | Customer Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Percent of net revenue by major customer			10.00%
Net revenue did not exceed ten percent	10.00%