Financial Instruments - Cash, Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Millions	Jun. 29, 2024	Sep. 30, 2023
Marketable Securities [Line Items]
Cash, Cash Equivalents and Marketable Securities, Adjusted Cost	$ 160,230	$ 173,752
Cash Equivalents and Marketable Securities, Unrealized Gains	220	30
Cash Equivalents and Marketable Securities, Unrealized Losses	(7,409)	(11,683)
Cash, Cash Equivalents and Marketable Securities, Fair Value	153,041	162,099
Cash and Cash Equivalents	25,565	29,965
Current Marketable Securities	36,236	31,590
Non-Current Marketable Securities	91,240	100,544
Total marketable securities that were restricted from general use	14,100	13,800
Level 1
Marketable Securities [Line Items]
Marketable Securities, Equity, Adjusted Cost	2,141	923
Marketable Securities, Equity, Unrealized Gains	76	12
Marketable Securities, Equity, Unrealized Losses	(7)	(26)
Marketable Securities, Equity, Fair Value	2,210	909
Cash and Cash Equivalents	1,648	481
Current Marketable Securities	562	428
Non-Current Marketable Securities	0	0
Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	135,223	144,470
Marketable Securities, Debt, Unrealized Gains	144	18
Marketable Securities, Debt, Unrealized Losses	(7,402)	(11,657)
Marketable Securities, Debt, Fair Value	127,965	132,831
Cash and Cash Equivalents	1,051	1,125
Current Marketable Securities	35,674	31,162
Non-Current Marketable Securities	91,240	100,544
Cash
Marketable Securities [Line Items]
Cash	22,866	28,359
Cash and Cash Equivalents	22,866	28,359
Current Marketable Securities	0	0
Non-Current Marketable Securities	0	0
Money market funds | Level 1
Marketable Securities [Line Items]
Marketable Securities, Equity, Adjusted Cost	1,648	481
Marketable Securities, Equity, Unrealized Gains	0	0
Marketable Securities, Equity, Unrealized Losses	0	0
Marketable Securities, Equity, Fair Value	1,648	481
Cash and Cash Equivalents	1,648	481
Current Marketable Securities	0	0
Non-Current Marketable Securities	0	0
Mutual funds | Level 1
Marketable Securities [Line Items]
Marketable Securities, Equity, Adjusted Cost	493
Marketable Securities, Equity, Unrealized Gains	76
Marketable Securities, Equity, Unrealized Losses	(7)
Marketable Securities, Equity, Fair Value	562
Cash and Cash Equivalents	0
Current Marketable Securities	562
Non-Current Marketable Securities	0
Mutual funds and equity securities | Level 1
Marketable Securities [Line Items]
Marketable Securities, Equity, Adjusted Cost		442
Marketable Securities, Equity, Unrealized Gains		12
Marketable Securities, Equity, Unrealized Losses		(26)
Marketable Securities, Equity, Fair Value		428
Cash and Cash Equivalents		0
Current Marketable Securities		428
Non-Current Marketable Securities		0
U.S. Treasury securities | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	16,298	19,406
Marketable Securities, Debt, Unrealized Gains	3	0
Marketable Securities, Debt, Unrealized Losses	(855)	(1,292)
Marketable Securities, Debt, Fair Value	15,446	18,114
Cash and Cash Equivalents	138	35
Current Marketable Securities	4,649	5,468
Non-Current Marketable Securities	10,659	12,611
U.S. agency securities | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	5,500	5,736
Marketable Securities, Debt, Unrealized Gains	0	0
Marketable Securities, Debt, Unrealized Losses	(418)	(600)
Marketable Securities, Debt, Fair Value	5,082	5,136
Cash and Cash Equivalents	73	36
Current Marketable Securities	518	271
Non-Current Marketable Securities	4,491	4,829
Non-U.S. government securities | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	17,560	17,533
Marketable Securities, Debt, Unrealized Gains	31	6
Marketable Securities, Debt, Unrealized Losses	(680)	(1,048)
Marketable Securities, Debt, Fair Value	16,911	16,491
Cash and Cash Equivalents	0	0
Current Marketable Securities	11,592	11,332
Non-Current Marketable Securities	5,319	5,159
Certificates of deposit and time deposits | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	1,337	1,354
Marketable Securities, Debt, Unrealized Gains	0	0
Marketable Securities, Debt, Unrealized Losses	0	0
Marketable Securities, Debt, Fair Value	1,337	1,354
Cash and Cash Equivalents	838	1,034
Current Marketable Securities	492	320
Non-Current Marketable Securities	7	0
Commercial paper | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	1,346	608
Marketable Securities, Debt, Unrealized Gains	0	0
Marketable Securities, Debt, Unrealized Losses	0	0
Marketable Securities, Debt, Fair Value	1,346	608
Cash and Cash Equivalents	2	0
Current Marketable Securities	1,344	608
Non-Current Marketable Securities	0	0
Corporate debt securities | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	68,194	76,840
Marketable Securities, Debt, Unrealized Gains	83	6
Marketable Securities, Debt, Unrealized Losses	(3,350)	(5,956)
Marketable Securities, Debt, Fair Value	64,927	70,890
Cash and Cash Equivalents	0	20
Current Marketable Securities	15,489	12,627
Non-Current Marketable Securities	49,438	58,243
Municipal securities | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	480	628
Marketable Securities, Debt, Unrealized Gains	0	0
Marketable Securities, Debt, Unrealized Losses	(13)	(26)
Marketable Securities, Debt, Fair Value	467	602
Cash and Cash Equivalents	0	0
Current Marketable Securities	197	192
Non-Current Marketable Securities	270	410
Mortgage- and asset-backed securities | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	24,508	22,365
Marketable Securities, Debt, Unrealized Gains	27	6
Marketable Securities, Debt, Unrealized Losses	(2,086)	(2,735)
Marketable Securities, Debt, Fair Value	22,449	19,636
Cash and Cash Equivalents	0	0
Current Marketable Securities	1,393	344
Non-Current Marketable Securities	$ 21,056	$ 19,292