Financial Instruments - Cash, Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Millions	Mar. 30, 2024	Sep. 30, 2023
Marketable Securities [Line Items]
Cash, Cash Equivalents and Marketable Securities, Adjusted Cost	$ 169,913	$ 173,752
Cash Equivalents and Marketable Securities, Unrealized Gains	231	30
Cash Equivalents and Marketable Securities, Unrealized Losses	(7,807)	(11,683)
Cash, Cash Equivalents and Marketable Securities, Fair Value	162,337	162,099
Cash and Cash Equivalents	32,695	29,965
Current Marketable Securities	34,455	31,590
Non-Current Marketable Securities	95,187	100,544
Total marketable securities that were restricted from general use	14,000	13,800
Level 1
Marketable Securities [Line Items]
Marketable Securities, Equity, Adjusted Cost	1,817	923
Marketable Securities, Equity, Unrealized Gains	66	12
Marketable Securities, Equity, Unrealized Losses	(7)	(26)
Marketable Securities, Equity, Fair Value	1,876	909
Cash and Cash Equivalents	1,353	481
Current Marketable Securities	523	428
Non-Current Marketable Securities	0	0
Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	139,869	144,470
Marketable Securities, Debt, Unrealized Gains	165	18
Marketable Securities, Debt, Unrealized Losses	(7,800)	(11,657)
Marketable Securities, Debt, Fair Value	132,234	132,831
Cash and Cash Equivalents	3,115	1,125
Current Marketable Securities	33,932	31,162
Non-Current Marketable Securities	95,187	100,544
Cash
Marketable Securities [Line Items]
Cash	28,227	28,359
Cash and Cash Equivalents	28,227	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	1,353	481
Marketable Securities, Equity, Unrealized Gains	0	0
Marketable Securities, Equity, Unrealized Losses	0	0
Marketable Securities, Equity, Fair Value	1,353	481
Cash and Cash Equivalents	1,353	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	464
Marketable Securities, Equity, Unrealized Gains	66
Marketable Securities, Equity, Unrealized Losses	(7)
Marketable Securities, Equity, Fair Value	523
Cash and Cash Equivalents	0
Current Marketable Securities	523
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	18,150	19,406
Marketable Securities, Debt, Unrealized Gains	1	0
Marketable Securities, Debt, Unrealized Losses	(933)	(1,292)
Marketable Securities, Debt, Fair Value	17,218	18,114
Cash and Cash Equivalents	1,895	35
Current Marketable Securities	4,133	5,468
Non-Current Marketable Securities	11,190	12,611
U.S. agency securities | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	5,775	5,736
Marketable Securities, Debt, Unrealized Gains	0	0
Marketable Securities, Debt, Unrealized Losses	(446)	(600)
Marketable Securities, Debt, Fair Value	5,329	5,136
Cash and Cash Equivalents	233	36
Current Marketable Securities	581	271
Non-Current Marketable Securities	4,515	4,829
Non-U.S. government securities | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	17,319	17,533
Marketable Securities, Debt, Unrealized Gains	37	6
Marketable Securities, Debt, Unrealized Losses	(666)	(1,048)
Marketable Securities, Debt, Fair Value	16,690	16,491
Cash and Cash Equivalents	0	0
Current Marketable Securities	11,289	11,332
Non-Current Marketable Securities	5,401	5,159
Certificates of deposit and time deposits | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	976	1,354
Marketable Securities, Debt, Unrealized Gains	0	0
Marketable Securities, Debt, Unrealized Losses	0	0
Marketable Securities, Debt, Fair Value	976	1,354
Cash and Cash Equivalents	656	1,034
Current Marketable Securities	320	320
Non-Current Marketable Securities	0	0
Commercial paper | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	1,482	608
Marketable Securities, Debt, Unrealized Gains	0	0
Marketable Securities, Debt, Unrealized Losses	0	0
Marketable Securities, Debt, Fair Value	1,482	608
Cash and Cash Equivalents	274	0
Current Marketable Securities	1,208	608
Non-Current Marketable Securities	0	0
Corporate debt securities | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	71,612	76,840
Marketable Securities, Debt, Unrealized Gains	90	6
Marketable Securities, Debt, Unrealized Losses	(3,694)	(5,956)
Marketable Securities, Debt, Fair Value	68,008	70,890
Cash and Cash Equivalents	57	20
Current Marketable Securities	15,096	12,627
Non-Current Marketable Securities	52,855	58,243
Municipal securities | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	511	628
Marketable Securities, Debt, Unrealized Gains	0	0
Marketable Securities, Debt, Unrealized Losses	(15)	(26)
Marketable Securities, Debt, Fair Value	496	602
Cash and Cash Equivalents	0	0
Current Marketable Securities	188	192
Non-Current Marketable Securities	308	410
Mortgage- and asset-backed securities | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	24,044	22,365
Marketable Securities, Debt, Unrealized Gains	37	6
Marketable Securities, Debt, Unrealized Losses	(2,046)	(2,735)
Marketable Securities, Debt, Fair Value	22,035	19,636
Cash and Cash Equivalents	0	0
Current Marketable Securities	1,117	344
Non-Current Marketable Securities	$ 20,918	$ 19,292