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 |