Fair Value (Unobservable Inputs Table) (Details) (Discounted Cash Flow)	3 Months Ended
	Apr. 28, 2012 yr
Student Loan Auction Rate Securities [Member] | Maximum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Market Rate of Return	1.85%
Term	19.60
Periodic Coupon Rate	4.31%
Student Loan Auction Rate Securities [Member] | Minimum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Market Rate of Return	0.24%
Term	6.60
Periodic Coupon Rate	0.27%
Muncipal Authority Auction Rate Securities [Member] | Maximum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Market Rate of Return	3.87%
Term	27.50
Periodic Coupon Rate	5.00%
Muncipal Authority Auction Rate Securities [Member] | Minimum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Market Rate of Return	0.02%
Term	22.00
Periodic Coupon Rate	0.37%