Fair Value Measurements (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) (USD $) In Millions, unless otherwise specified	Dec. 30, 2011	Dec. 31, 2010
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	$ 843.9	$ 925.7
Other marketable securities	190.9	213.6
Derivative financial instruments - Assets	0.2	0.2
Total assets	1,035.0	1,139.5
Loan related to other marketable securities	190.9	213.6
Derivative financial instruments - Liabilities	0.2	1.0
Total liabilities	191.1	214.6
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	195.7	258.4
Other marketable securities	190.9	213.6
Total assets	386.6	472.0
Loan related to other marketable securities	190.9	213.6
Total liabilities	190.9	213.6
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	648.2	667.3
Derivative financial instruments - Assets	0.2	0.2
Total assets	648.4	667.5
Derivative financial instruments - Liabilities	0.2	1.0
Total liabilities	0.2	1.0
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities
Other marketable securities
Derivative financial instruments - Assets
Total assets
Loan related to other marketable securities
Derivative financial instruments - Liabilities
Total liabilities
Foreign Government Debt Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	223.0	202.1
Foreign Government Debt Obligations [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	223.0	202.1
Foreign Government Debt Obligations [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities
Certificates Of Deposit Guaranteed By FDIC [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	1.5	3.3
Certificates Of Deposit Guaranteed By FDIC [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	1.5	3.3
Certificates Of Deposit Guaranteed By FDIC [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities
Mortgage Backed Debt Obligations Guaranteed By GNMA [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	91.2	175.1
Mortgage Backed Debt Obligations Guaranteed By GNMA [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	91.2	175.1
Mortgage Backed Debt Obligations Guaranteed By GNMA [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities
U.S. Government Debt Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	195.7	258.4
U.S. Government Debt Obligations [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	195.7	258.4
U.S. Government Debt Obligations [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities
Corporate Debt Obligations Guaranteed By FDIC [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	66.8	102.6
Corporate Debt Obligations Guaranteed By FDIC [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	66.8	102.6
Corporate Debt Obligations Guaranteed By FDIC [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities
Corporate Debt Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	201.5	95.9
Corporate Debt Obligations [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	201.5	95.9
Corporate Debt Obligations [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities
Foreign Corporate Debt Obligations Guaranteed By Foreign Governments [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	64.2	88.3
Foreign Corporate Debt Obligations Guaranteed By Foreign Governments [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities	64.2	88.3
Foreign Corporate Debt Obligations Guaranteed By Foreign Governments [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in marketable securities