Composition of Certain Financial Statement Items Investment and Other Income, Net (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Mar. 31, 2019	Mar. 25, 2018	Mar. 31, 2019	Mar. 25, 2018
Investment Income, Net [Abstract]
Interest and dividend income	$ 80	$ 154	$ 155	$ 280
Net gains (losses) on marketable securities	40	3	(33)	13
Net gains on other investments	6	47	42	60
Impairment losses on marketable securities and other investments	(60)	(11)	(69)	(20)
Net (losses) gains on derivative investments	(1)	10	(9)	9
Equity in net losses of investees	(36)	(17)	(58)	(38)
Net (losses) gains on foreign currency transactions	(1)	(90)	5	(93)
Investment and other income, net	$ 28	$ 96	$ 33	$ 211

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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Amount before tax of foreign currency transaction realized and unrealized gain (loss) recognized in the income statement.

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Amount of realized gain (loss) on investment in marketable security, excluding other-than-temporary impairment (OTTI).

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