Segment Information - Operating Results Information for Each Reportable Segment (Detail) (USD $)	3 Months Ended									12 Months Ended
	Sep. 26, 2014	Jun. 27, 2014	Mar. 28, 2014		Dec. 27, 2013	Sep. 27, 2013	Jun. 28, 2013	Mar. 29, 2013	Dec. 28, 2012	Sep. 26, 2014		Sep. 27, 2013		Sep. 28, 2012
Segment Reporting Information [Line Items]
Revenues	$ 812,100,000	$ 747,700,000	$ 778,500,000	[1]	$ 711,500,000	$ 769,900,000	$ 726,200,000	$ 768,400,000	$ 678,400,000	$ 3,049,800,000		$ 2,942,897,000		$ 2,807,015,000
Operating Earnings										571,155,000	[2]	608,890,000	[2]	594,074,000	[2]
Depreciation & Amortization										62,500,000		62,900,000		61,000,000
Total Assets	3,357,290,000					3,468,474,000				3,357,290,000		3,468,474,000		2,878,700,000
Corporate
Segment Reporting Information [Line Items]
Operating Earnings										(41,500,000)	[2]	(22,300,000)	[2]	(9,600,000)	[2]
Depreciation & Amortization										22,000,000		25,900,000		23,800,000
Total Assets	1,333,000,000					1,574,900,000				1,333,000,000		1,574,900,000		1,081,000,000
Operating Segments | Oncology Systems
Segment Reporting Information [Line Items]
Revenues										2,344,200,000		2,252,700,000		2,189,500,000
Operating Earnings										495,500,000	[2]	512,000,000	[2]	505,400,000	[2]
Depreciation & Amortization										24,800,000		21,000,000		22,900,000
Total Assets	1,314,100,000					1,217,000,000				1,314,100,000		1,217,000,000		1,220,100,000
Operating Segments | Imaging Components
Segment Reporting Information [Line Items]
Revenues										660,200,000		641,900,000		580,400,000
Operating Earnings										169,900,000	[2]	165,600,000	[2]	142,500,000	[2]
Depreciation & Amortization										14,700,000		14,600,000		12,300,000
Total Assets	431,600,000					398,500,000				431,600,000		398,500,000		356,100,000
Operating Segments | Total Reportable Segments
Segment Reporting Information [Line Items]
Revenues										3,004,400,000		2,894,600,000		2,769,900,000
Operating Earnings										665,400,000	[2]	677,600,000	[2]	647,900,000	[2]
Depreciation & Amortization										39,500,000		35,600,000		35,200,000
Total Assets	1,745,700,000					1,615,500,000				1,745,700,000		1,615,500,000		1,576,200,000
Operating Segments | Other
Segment Reporting Information [Line Items]
Revenues										45,400,000		48,300,000		37,100,000
Operating Earnings										(52,700,000)	[2]	(46,400,000)	[2]	(44,200,000)	[2]
Depreciation & Amortization										1,000,000		1,400,000		2,000,000
Total Assets	$ 278,600,000					$ 278,100,000				$ 278,600,000		$ 278,100,000		$ 221,500,000

[1] In the second fiscal quarter of 2014, net earnings include a $25.1 million litigation charge related to a settlement agreement with the University of Pittsburgh.

[2] Operating earnings of reportable segments and Other include an allocation of corporate expenses based on a percentage of their sales.