Segment Information - Financial Information by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 30, 2016	Sep. 30, 2016	Jul. 01, 2016	Apr. 01, 2016	Jan. 01, 2016	Oct. 02, 2015	Jun. 26, 2015	Mar. 27, 2015	Dec. 26, 2014	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 2,653,866	$ 2,514,751	$ 2,302,567	$ 2,551,604	$ 2,640,587	$ 2,693,873	$ 2,781,763	$ 2,847,934	$ 3,116,954	$ 2,907,541	$ 2,903,332	$ 3,187,005	$ 10,022,788	$ 10,964,157	$ 12,114,832
Property, equipment and improvements, net	349,911				319,673				381,238				349,911	319,673	381,238
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues													5,822,843	6,247,448	7,154,433
Property, equipment and improvements, net	220,416				195,392				208,155				220,416	195,392	208,155
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues													2,262,092	2,346,224	2,074,837
Property, equipment and improvements, net	46,108				37,163				55,713				46,108	37,163	55,713
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues													590,604	927,942	1,065,651
Property, equipment and improvements, net	18,435				21,464				36,647				18,435	21,464	36,647
Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues													253,167	299,952	304,393
Property, equipment and improvements, net	2,793				3,069				3,859				2,793	3,069	3,859
India
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues													165,295	187,929	163,871
Property, equipment and improvements, net	19,191				13,350				16,264				19,191	13,350	16,264
Australia and New Zealand
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues													628,945	436,670	611,271
Property, equipment and improvements, net	18,692				18,888				24,460				18,692	18,888	24,460
South America and Mexico
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues													73,456	125,610	143,014
Property, equipment and improvements, net	4,619				5,621				9,127				4,619	5,621	9,127
Middle East and Africa
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues													226,386	392,382	597,362
Property, equipment and improvements, net	$ 19,657				$ 24,726				$ 27,013				$ 19,657	$ 24,726	$ 27,013