Segment and Geographic Data - By Region (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 27, 2019	Jun. 28, 2019	Mar. 29, 2019	Dec. 28, 2018	Sep. 28, 2018	Jun. 29, 2018	Mar. 30, 2018	Dec. 29, 2017	Sep. 27, 2019	Sep. 28, 2018	Sep. 29, 2017
Segment and Geographic Data
Net sales	$ 3,300	$ 3,389	$ 3,412	$ 3,347	$ 3,509	$ 3,581	$ 3,562	$ 3,336	$ 13,448	$ 13,988	$ 12,185
Property, Plant, and Equipment, Net	3,574				3,497				3,574	3,497	3,159
Switzerland
Segment and Geographic Data
Net sales									3,251	3,478	3,016
Property, Plant, and Equipment, Net	92				94				92	94	80
Germany
Segment and Geographic Data
Net sales									404	443	235
Property, Plant, and Equipment, Net	443				448				443	448	413
Other Europe/Middle East/Africa
Segment and Geographic Data
Net sales									1,168	1,334	1,148
Property, Plant, and Equipment, Net	851				829				851	829	741
Total Europe/Middle East/Africa
Segment and Geographic Data
Net sales									4,823	5,255	4,399
Property, Plant, and Equipment, Net	1,386				1,371				1,386	1,371	1,234
China
Segment and Geographic Data
Net sales									2,443	2,739	2,414
Property, Plant, and Equipment, Net	642				627				642	627	555
Other Asia-Pacific
Segment and Geographic Data
Net sales									1,958	2,023	1,898
Property, Plant, and Equipment, Net	449				436				449	436	390
Total Asia-Pacific
Segment and Geographic Data
Net sales									4,401	4,762	4,312
Property, Plant, and Equipment, Net	1,091				1,063				1,091	1,063	945
U.S.
Segment and Geographic Data
Net sales									3,794	3,583	3,136
Property, Plant, and Equipment, Net	991				964				991	964	880
Other Americas
Segment and Geographic Data
Net sales									430	388	338
Property, Plant, and Equipment, Net	106				99				106	99	100
Total Americas
Segment and Geographic Data
Net sales									4,224	3,971	3,474
Property, Plant, and Equipment, Net	$ 1,097				$ 1,063				$ 1,097	$ 1,063	$ 980