Fair Value Measurements - Additional Information (Detail) (USD $)	3 Months Ended					12 Months Ended			3 Months Ended						12 Months Ended	3 Months Ended
	Jun. 28, 2014	Mar. 29, 2014	Dec. 28, 2013	Sep. 28, 2013	Sep. 29, 2012	Sep. 27, 2014	Sep. 28, 2013	Sep. 29, 2012	Mar. 29, 2014 Property, Plant and Equipment [Member]	Sep. 27, 2014 Credit Agreement [Member]	Aug. 01, 2012 Credit Agreement [Member]	Sep. 27, 2014 Senior Notes [Member]	Sep. 28, 2013 Senior Notes [Member]	Sep. 28, 2013 Fair Value, Inputs, Level 3 [Member]	Sep. 27, 2014 Diagnostics [Member]	Sep. 27, 2014 Diagnostics [Member] Fair Value, Inputs, Level 3 [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Cost-method equity investments				$ 1,500,000			$ 1,500,000							$ 1,500,000
Impairment of goodwill				1,100,000,000	5,800,000	0	1,117,400,000	5,800,000							0
Impairment charge		28,600,000		700,000			3,700,000	6,500,000
Impairment charge allocated to intangible assets		27,100,000
Non-cash impairment charges						38,400,000	9,400,000	16,900,000	1,500,000							5,100,000
Asset impairment charge			3,100,000				5,000,000	6,500,000
Cost-method equity investments in non-publicly traded securities				12,600,000		5,200,000	12,600,000
Other-than-temporary impairment charges	6,900,000					6,400,000
Borrowed principal under credit agreement										2,050,000,000	2,500,000,000
Fair value of debt instrument												$ 1,030,000,000	$ 1,050,000,000