Goodwill And Intangible Assets (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 30, 2011	Oct. 31, 2010	Oct. 30, 2011	Oct. 31, 2010	Dec. 09, 2009 Core Technologies [Member]
Finite and Indefinite Lived Intangible Assets [Line Items]
Changes to goodwill			$ 0
Intangible assets from acquisition of Sierra Monolithics, Inc.					59.9
Amortization expense related to finite-lived intangible assets	$ 2.1	$ 2.4	$ 6.3	$ 7.2