Retirement Plans - Defined Benefit Pension Plan Asset Categories and Fair Value Hierarchy (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 25, 2015	Sep. 26, 2014
U.S. Plans
Summary of asset fair value
Fair value of plan assets	$ 929	$ 879	$ 978
U.S. Plans | Fair Value
Summary of asset fair value
Fair value of plan assets	929	879
U.S. Plans | U.S. equity securities | Level 1
Summary of asset fair value
Fair value of plan assets	248	245
U.S. Plans | U.S. equity securities | Fair Value
Summary of asset fair value
Fair value of plan assets	248	245
U.S. Plans | Non-U.S. equity securities | Level 1
Summary of asset fair value
Fair value of plan assets	190	149
U.S. Plans | Non-U.S. equity securities | Fair Value
Summary of asset fair value
Fair value of plan assets	190	149
U.S. Plans | Government bonds | Level 2
Summary of asset fair value
Fair value of plan assets	67	64
U.S. Plans | Government bonds | Fair Value
Summary of asset fair value
Fair value of plan assets	67	64
U.S. Plans | Corporate bonds | Level 2
Summary of asset fair value
Fair value of plan assets	397	404
U.S. Plans | Corporate bonds | Fair Value
Summary of asset fair value
Fair value of plan assets	397	404
U.S. Plans | Other | Level 2
Summary of asset fair value
Fair value of plan assets	11	3
U.S. Plans | Other | Fair Value
Summary of asset fair value
Fair value of plan assets	11	3
U.S. Plans | Subtotal | Level 1
Summary of asset fair value
Fair value of plan assets	438	394
U.S. Plans | Subtotal | Level 2
Summary of asset fair value
Fair value of plan assets	475	471
U.S. Plans | Subtotal | Fair Value
Summary of asset fair value
Fair value of plan assets	913	865
U.S. Plans | Items to reconcile to fair value of plan assets | Fair Value
Summary of asset fair value
Fair value of plan assets	16	14
Non-U.S. Plans
Summary of asset fair value
Fair value of plan assets	1,371	1,167	$ 1,177
Non-U.S. Plans | Fair Value
Summary of asset fair value
Fair value of plan assets	1,371	1,167
Non-U.S. Plans | U.S. equity securities | Level 1
Summary of asset fair value
Fair value of plan assets	64	60
Non-U.S. Plans | U.S. equity securities | Fair Value
Summary of asset fair value
Fair value of plan assets	64	60
Non-U.S. Plans | Non-U.S. equity securities | Level 1
Summary of asset fair value
Fair value of plan assets	62	54
Non-U.S. Plans | Non-U.S. equity securities | Fair Value
Summary of asset fair value
Fair value of plan assets	62	54
Non-U.S. Plans | Commingled equity funds | Level 2
Summary of asset fair value
Fair value of plan assets	456	421
Non-U.S. Plans | Commingled equity funds | Fair Value
Summary of asset fair value
Fair value of plan assets	456	421
Non-U.S. Plans | Government bonds | Level 2
Summary of asset fair value
Fair value of plan assets	226	202
Non-U.S. Plans | Government bonds | Fair Value
Summary of asset fair value
Fair value of plan assets	226	202
Non-U.S. Plans | Corporate bonds | Level 2
Summary of asset fair value
Fair value of plan assets	13	13
Non-U.S. Plans | Corporate bonds | Fair Value
Summary of asset fair value
Fair value of plan assets	13	13
Non-U.S. Plans | Commingled bond funds | Level 2
Summary of asset fair value
Fair value of plan assets	262	171
Non-U.S. Plans | Commingled bond funds | Fair Value
Summary of asset fair value
Fair value of plan assets	262	171
Non-U.S. Plans | Other | Level 2
Summary of asset fair value
Fair value of plan assets	177	142
Non-U.S. Plans | Other | Level 3
Summary of asset fair value
Fair value of plan assets	91	84
Non-U.S. Plans | Other | Fair Value
Summary of asset fair value
Fair value of plan assets	268	226
Non-U.S. Plans | Subtotal | Level 1
Summary of asset fair value
Fair value of plan assets	126	114
Non-U.S. Plans | Subtotal | Level 2
Summary of asset fair value
Fair value of plan assets	1,134	949
Non-U.S. Plans | Subtotal | Level 3
Summary of asset fair value
Fair value of plan assets	91	84
Non-U.S. Plans | Subtotal | Fair Value
Summary of asset fair value
Fair value of plan assets	1,351	1,147
Non-U.S. Plans | Items to reconcile to fair value of plan assets | Fair Value
Summary of asset fair value
Fair value of plan assets	$ 20	$ 20