Quarterly report pursuant to Section 13 or 15(d)

Investments (Details)

v2.4.0.8
Investments (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended
Mar. 29, 2014
Mar. 30, 2013
Dec. 31, 2013
Schedule of Investments [Line Items]      
Maturity Of Investments, Maximum 2 years    
Amortized cost $ 0.8   $ 12.7
Gross unrealized gains 0   0
Gross unrealized losses 0   0
Fair value (net carrying amount) 0.8   12.7
Available-for-sale debt securities [Abstract]      
Due in one year or less, amortized cost 0.8   12.7
Total available-for-sale debt securities, amortized cost 0.8   12.7
Due in one year or less, fair value (net carrying amount) 0.8   12.7
Total available-for-sale debt securities, fair value (net carrying amount) 0.8   12.7
Redemptions of available-for-sale securities 11.9 80.6  
Net adjustment to unrealized investment losses on available-for-sale securities 0 0  
U.S. Treasury Bills [Member]
      
Schedule of Investments [Line Items]      
Amortized cost 0.8   0.8
Gross unrealized gains 0   0
Gross unrealized losses 0   0
Fair value (net carrying amount) 0.8   0.8
Corporate Bonds [Member]
      
Schedule of Investments [Line Items]      
Amortized cost     11.9
Gross unrealized gains     0
Gross unrealized losses     0
Fair value (net carrying amount)     $ 11.9