Operating Results Information for Each Reportable Segment (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 28, 2014	Mar. 29, 2013	Mar. 28, 2014	Mar. 29, 2013
Segment Reporting Information [Line Items]
Revenues	$ 778,506	$ 768,358	$ 1,490,008	$ 1,446,756
Operating Earnings (Loss)	127,544	155,704	269,538	293,194
Operating Segments | Oncology Systems
Segment Reporting Information [Line Items]
Revenues	603,100	581,800	1,144,500	1,106,100
Operating Earnings (Loss)	124,900	131,300	245,800	251,500
Operating Segments | Imaging Components
Segment Reporting Information [Line Items]
Revenues	169,000	166,400	330,200	316,400
Operating Earnings (Loss)	42,200	43,500	82,900	78,700
Operating Segments | Total reportable segments
Segment Reporting Information [Line Items]
Revenues	772,100	748,200	1,474,700	1,422,500
Operating Earnings (Loss)	167,100	174,800	328,700	330,200
Operating Segments | Other
Segment Reporting Information [Line Items]
Revenues	6,400	20,200	15,300	24,300
Operating Earnings (Loss)	(14,500)	(12,100)	(28,700)	(23,800)
Corporate
Segment Reporting Information [Line Items]
Operating Earnings (Loss)	$ (25,100)	$ (7,000)	$ (30,500)	$ (13,200)