Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $) In Millions, unless otherwise specified	Jun. 29, 2012	Dec. 30, 2011
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	$ 771.2	$ 843.9
Other marketable securities	181.3	190.9
Derivative financial instruments	0.4	0.2
Total Assets	952.9	1,035.0
Loan related to other marketable securities	181.3	190.9
Derivative financial instruments	0.5	0.2
Total Liabilities	181.8	191.1
U.S. government debt obligations
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	158.7	195.7
Corporate debt obligations guaranteed By FDIC
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	20.3	66.8
Corporate debt obligations
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	191.4	201.5
Mortgaged backed debt obligations guaranteed by GNMA
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	90.0	91.2
Certificates of deposit guaranteed by FDIC
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	1.2	1.5
Foreign government debt obligations
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	194.5	223.0
Foreign corporate debt obligations
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	115.1	64.2
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	158.7	195.7
Other marketable securities	181.3	190.9
Total Assets	340.0	386.6
Loan related to other marketable securities	181.3	190.9
Total Liabilities	181.3	190.9
Fair Value, Inputs, Level 1 | U.S. government debt obligations
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	158.7	195.7
Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	612.5	648.2
Derivative financial instruments	0.4	0.2
Total Assets	612.9	648.4
Derivative financial instruments	0.5	0.2
Total Liabilities	0.5	0.2
Fair Value, Inputs, Level 2 | Corporate debt obligations guaranteed By FDIC
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	20.3	66.8
Fair Value, Inputs, Level 2 | Corporate debt obligations
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	191.4	201.5
Fair Value, 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	90.0	91.2
Fair Value, Inputs, Level 2 | Certificates of deposit guaranteed by FDIC
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	1.2	1.5
Fair Value, Inputs, Level 2 | Foreign government debt obligations
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	194.5	223.0
Fair Value, Inputs, Level 2 | Foreign corporate debt obligations
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	$ 115.1	$ 64.2