Goodwill and Intangible Assets (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Mar. 25, 2016	Sep. 25, 2015	Sep. 26, 2014
Changes in the carrying amount of goodwill, by segment ($ in millions):
Goodwill balance at beginning of period	$ 4,234	$ 4,119
Accumulated impairment	(1,761)	(1,761)	$ (1,761)
Acquisitions / purchase accounting adjustments	251	347
Currency translation	(25)	(232)
Goodwill balance at end of period	4,460	4,234
Gross Goodwill
Changes in the carrying amount of goodwill, by segment ($ in millions):
Goodwill balance at beginning of period	5,995	5,880
Goodwill balance at end of period	6,221	5,995
NA Installation & Services
Changes in the carrying amount of goodwill, by segment ($ in millions):
Goodwill balance at beginning of period	1,970	1,976
Accumulated impairment	(126)	(126)	(126)
Acquisitions / purchase accounting adjustments	69	23
Currency translation	1	(29)
Goodwill balance at end of period	2,040	1,970
NA Installation & Services | Gross Goodwill
Changes in the carrying amount of goodwill, by segment ($ in millions):
Goodwill balance at beginning of period	2,096	2,102
Goodwill balance at end of period	2,166	2,096
ROW Installation & Services
Changes in the carrying amount of goodwill, by segment ($ in millions):
Goodwill balance at beginning of period	784	901
Accumulated impairment	(1,068)	(1,068)	(1,068)
Acquisitions / purchase accounting adjustments	182	50
Currency translation	(20)	(167)
Goodwill balance at end of period	946	784
ROW Installation & Services | Gross Goodwill
Changes in the carrying amount of goodwill, by segment ($ in millions):
Goodwill balance at beginning of period	1,852	1,969
Goodwill balance at end of period	2,014	1,852
Global Products
Changes in the carrying amount of goodwill, by segment ($ in millions):
Goodwill balance at beginning of period	1,480	1,242
Accumulated impairment	(567)	(567)	$ (567)
Acquisitions / purchase accounting adjustments	0	274
Currency translation	(6)	(36)
Goodwill balance at end of period	1,474	1,480
Global Products | Gross Goodwill
Changes in the carrying amount of goodwill, by segment ($ in millions):
Goodwill balance at beginning of period	2,047	1,809
Goodwill balance at end of period	$ 2,041	$ 2,047