Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $) In Millions, unless otherwise specified	Sep. 28, 2012	Dec. 30, 2011
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	$ 806.9	$ 843.9
Other marketable securities	201.6	190.9
Derivative financial instruments	0.1	0.2
Total Assets	1,008.6	1,035.0
Loan related to other marketable securities	201.6	190.9
Derivative financial instruments	2.4	0.2
Total Liabilities	204.0	191.1
U.S. government debt obligations
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	152.4	195.7
Corporate debt obligations guaranteed By FDIC
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	21.1	66.8
Corporate debt obligations
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	188.6	201.5
Mortgaged backed debt obligations guaranteed by GNMA
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	97.7	91.2
Certificates of deposit guaranteed by FDIC
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	3.2	1.5
Foreign government debt obligations
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	224.7	223.0
Foreign corporate debt obligations
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	119.2	64.2
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	152.4	195.7
Other marketable securities	201.6	190.9
Total Assets	354.0	386.6
Loan related to other marketable securities	201.6	190.9
Total Liabilities	201.6	190.9
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. government debt obligations
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	152.4	195.7
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	654.5	648.2
Derivative financial instruments	0.1	0.2
Total Assets	654.6	648.4
Derivative financial instruments	2.4	0.2
Total Liabilities	2.4	0.2
Significant Other Observable Inputs (Level 2) | Corporate debt obligations guaranteed By FDIC
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	21.1	66.8
Significant Other Observable Inputs (Level 2) | Corporate debt obligations
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	188.6	201.5
Significant Other Observable Inputs (Level 2) | Mortgaged backed debt obligations guaranteed by GNMA
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	97.7	91.2
Significant Other Observable Inputs (Level 2) | Certificates of deposit guaranteed by FDIC
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	3.2	1.5
Significant Other Observable Inputs (Level 2) | Foreign government debt obligations
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	224.7	223.0
Significant Other Observable Inputs (Level 2) | Foreign corporate debt obligations
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	$ 119.2	$ 64.2