Cash and Cash Equivalents and Restricted Cash Cash and Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Millions	Jun. 30, 2018	Sep. 30, 2017	Jul. 01, 2017	Oct. 01, 2016
Cash and Cash Equivalents [Abstract]
Cash and Cash Equivalents	$ 4,326	$ 4,017
Other Current Assets	1	26
Other Assets	4	21
Cash, Cash Equivalents and Restricted Cash	$ 4,331	$ 4,064	$ 4,428	$ 4,760