Investments - Narrative (Details)	6 Months Ended
	Jul. 26, 2015
Minimum [Member]
Investment [Line Items]
Investment maturity period	3 months
Short-term Investments [Member] | Minimum [Member]
Investment [Line Items]
Investment maturity period	3 months
Short-term Investments [Member] | Maximum [Member]
Investment [Line Items]
Investment maturity period	12 months
Other Long-term Investments [Member] | Minimum [Member]
Investment [Line Items]
Investment maturity period	12 months