Balance Sheet Details (Depreciation And Amortization Expense) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Apr. 27, 2012	Apr. 29, 2011	Apr. 30, 2010
Balance Sheet Details [Abstract]
Depreciation and amortization expense	$ 204.1	$ 147.9	$ 145.4

Depreciation And Amortization Expense Property And Equipment

No definition available.

Name:	ntap_DepreciationAndAmortizationExpensePropertyAndEquipment
Namespace Prefix:	ntap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration