Financial Instruments - Cash, Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Millions	Dec. 27, 2025	Sep. 27, 2025
Marketable Securities [Line Items]
Cash, Cash Equivalents and Marketable Securities, Adjusted Cost	$ 146,519	$ 134,711
Cash Equivalents and Marketable Securities, Unrealized Gains	815	736
Cash Equivalents and Marketable Securities, Unrealized Losses	(2,539)	(3,027)
Cash, Cash Equivalents and Marketable Securities, Fair Value	144,795	132,420
Cash and Cash Equivalents	45,317	35,934
Current Marketable Securities	21,590	18,763
Non-Current Marketable Securities	77,888	77,723
Level 1
Marketable Securities [Line Items]
Marketable Securities, Equity, Adjusted Cost	6,751	5,951
Marketable Securities, Equity, Unrealized Gains	195	177
Marketable Securities, Equity, Unrealized Losses	(2)	(2)
Marketable Securities, Equity, Fair Value	6,944	6,126
Cash and Cash Equivalents	5,959	5,272
Current Marketable Securities	985	854
Non-Current Marketable Securities	0	0
Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	108,942	100,493
Marketable Securities, Debt, Unrealized Gains	620	559
Marketable Securities, Debt, Unrealized Losses	(2,537)	(3,025)
Marketable Securities, Debt, Fair Value	107,025	98,027
Cash and Cash Equivalents	8,532	2,395
Current Marketable Securities	20,605	17,909
Non-Current Marketable Securities	77,888	77,723
Cash
Marketable Securities [Line Items]
Cash	30,826	28,267
Cash and Cash Equivalents	30,826	28,267
Money market funds | Level 1
Marketable Securities [Line Items]
Marketable Securities, Equity, Adjusted Cost	5,959	5,272
Marketable Securities, Equity, Unrealized Gains	0	0
Marketable Securities, Equity, Unrealized Losses	0	0
Marketable Securities, Equity, Fair Value	5,959	5,272
Cash and Cash Equivalents	5,959	5,272
Current Marketable Securities	0	0
Non-Current Marketable Securities	0	0
Mutual funds | Level 1
Marketable Securities [Line Items]
Marketable Securities, Equity, Adjusted Cost	792	679
Marketable Securities, Equity, Unrealized Gains	195	177
Marketable Securities, Equity, Unrealized Losses	(2)	(2)
Marketable Securities, Equity, Fair Value	985	854
Cash and Cash Equivalents	0	0
Current Marketable Securities	985	854
Non-Current Marketable Securities	0	0
U.S. Treasury securities | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	18,715	16,074
Marketable Securities, Debt, Unrealized Gains	64	56
Marketable Securities, Debt, Unrealized Losses	(211)	(282)
Marketable Securities, Debt, Fair Value	18,568	15,848
Cash and Cash Equivalents	2,302	1,190
Current Marketable Securities	5,341	3,712
Non-Current Marketable Securities	10,925	10,946
U.S. agency securities | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	8,692	5,269
Marketable Securities, Debt, Unrealized Gains	1	0
Marketable Securities, Debt, Unrealized Losses	(114)	(149)
Marketable Securities, Debt, Fair Value	8,579	5,120
Cash and Cash Equivalents	4,192	251
Current Marketable Securities	1,998	2,456
Non-Current Marketable Securities	2,389	2,413
Non-U.S. government securities | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	6,675	6,586
Marketable Securities, Debt, Unrealized Gains	117	111
Marketable Securities, Debt, Unrealized Losses	(399)	(424)
Marketable Securities, Debt, Fair Value	6,393	6,273
Cash and Cash Equivalents	0	0
Current Marketable Securities	771	855
Non-Current Marketable Securities	5,622	5,418
Certificates of deposit and time deposits | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	1,737	917
Marketable Securities, Debt, Unrealized Gains	0	0
Marketable Securities, Debt, Unrealized Losses	0	0
Marketable Securities, Debt, Fair Value	1,737	917
Cash and Cash Equivalents	1,723	904
Current Marketable Securities	0	0
Non-Current Marketable Securities	14	13
Commercial paper | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	991	100
Marketable Securities, Debt, Unrealized Gains	0	0
Marketable Securities, Debt, Unrealized Losses	0	0
Marketable Securities, Debt, Fair Value	991	100
Cash and Cash Equivalents	297	50
Current Marketable Securities	694	50
Non-Current Marketable Securities	0	0
Corporate debt securities | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	46,682	47,210
Marketable Securities, Debt, Unrealized Gains	280	266
Marketable Securities, Debt, Unrealized Losses	(695)	(916)
Marketable Securities, Debt, Fair Value	46,267	46,560
Cash and Cash Equivalents	18	0
Current Marketable Securities	11,568	10,623
Non-Current Marketable Securities	34,681	35,937
Municipal securities | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	154	207
Marketable Securities, Debt, Unrealized Gains	0	0
Marketable Securities, Debt, Unrealized Losses	(1)	(2)
Marketable Securities, Debt, Fair Value	153	205
Cash and Cash Equivalents	0	0
Current Marketable Securities	97	119
Non-Current Marketable Securities	56	86
Mortgage- and asset-backed securities | Level 2
Marketable Securities [Line Items]
Marketable Securities, Debt, Adjusted Cost	25,296	24,130
Marketable Securities, Debt, Unrealized Gains	158	126
Marketable Securities, Debt, Unrealized Losses	(1,117)	(1,252)
Marketable Securities, Debt, Fair Value	24,337	23,004
Cash and Cash Equivalents	0	0
Current Marketable Securities	136	94
Non-Current Marketable Securities	$ 24,201	$ 22,910