Goodwill and Intangible Assets (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 28, 2012	Oct. 30, 2011	Oct. 28, 2012	Oct. 30, 2011
Goodwill and Intangible Assets [Line Items]
Goodwill increase due to acquisitions			$ 264.9
Amortization expense related to finite-lived intangible assets	8.2	2.1	21.1	6.3
Increase (decrease) in indefinite-lived intangible assets			22.5
Technology Licenses [Member]
Goodwill and Intangible Assets [Line Items]
Increase in finite-lived intangible assets			2.5
In-Process Research And Development [Member]
Goodwill and Intangible Assets [Line Items]
Increase in finite-lived intangible assets			6.6
In-Process Research And Development [Member]
Goodwill and Intangible Assets [Line Items]
Increase (decrease) in indefinite-lived intangible assets			(6.6)
Gennum [Member]
Goodwill and Intangible Assets [Line Items]
Finite-lived intangible assets from acquisition	129.9		129.9
Indefinite-lived intangible assets from acquisition	29.1		29.1
Gennum [Member] | Core Technologies [Member]
Goodwill and Intangible Assets [Line Items]
Finite-lived intangible assets from acquisition	95.1		95.1
Cycleo [Member]
Goodwill and Intangible Assets [Line Items]
Finite-lived intangible assets from acquisition	6.1		6.1
Cycleo [Member] | Core Technologies [Member]
Goodwill and Intangible Assets [Line Items]
Finite-lived intangible assets from acquisition	$ 6.1		$ 6.1