Financial Instruments and Fair Value Measurements (Schedule of Fair Value of Assets and Liabilities Measured on a Recurring Basis) (Details) (Recurring, USD $) In Millions, unless otherwise specified	Dec. 26, 2014	Sep. 26, 2014
Assets:
Debt and equity securities held in rabbi trusts	$ 36.7	$ 35.7
Liabilities:
Deferred compensation liabilities	19.1	15.0
Contingent consideration and acquired contingent liabilities	202.9	202.8
Foreign exchange forward and option contracts	4.3	0.2
Total liabilities at fair value	226.3	218.0
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Debt and equity securities held in rabbi trusts	24.3	22.9
Liabilities:
Deferred compensation liabilities	0	0
Contingent consideration and acquired contingent liabilities	0	0
Foreign exchange forward and option contracts	4.3	0.2
Total liabilities at fair value	4.3	0.2
Significant Other Observable Inputs (Level 2)
Assets:
Debt and equity securities held in rabbi trusts	12.4	12.8
Liabilities:
Deferred compensation liabilities	19.1	15.0
Contingent consideration and acquired contingent liabilities	0	0
Foreign exchange forward and option contracts	0	0
Total liabilities at fair value	19.1	15.0
Significant Unobservable Inputs (Level 3)
Assets:
Debt and equity securities held in rabbi trusts	0	0
Liabilities:
Deferred compensation liabilities	0	0
Contingent consideration and acquired contingent liabilities	202.9	202.8
Foreign exchange forward and option contracts	0	0
Total liabilities at fair value	$ 202.9	$ 202.8