Financial Instruments - Cash, Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Millions | Dec. 25, 2021 | Sep. 25, 2021 |
Debt Securities, Available-for-sale [Line Items] | | |
Cash, Cash Equivalents and Marketable Securities, Adjusted Cost | $ 203,819 | $ 189,961 |
Cash Equivalents and Marketable Securities, Unrealized Gains | 1,071 | 1,753 |
Cash Equivalents and Marketable Securities, Unrealized Losses | 2,294 | 1,198 |
Cash, Cash Equivalents and Marketable Securities, Fair Value | 202,596 | 190,516 |
Cash and Cash Equivalents | 37,119 | 34,940 |
Current Marketable Securities | 26,794 | 27,699 |
Non-Current Marketable Securities | 138,683 | 127,877 |
Total marketable securities that were restricted from general use | 16,800 | 17,900 |
Level 1 | | |
Debt Securities, Available-for-sale [Line Items] | | |
Marketable Securities, Equity, Adjusted Cost | 11,571 | 9,783 |
Marketable Securities, Equity, Unrealized Gains | 16 | 11 |
Marketable Securities, Equity, Unrealized Losses | (2) | (1) |
Marketable Securities, Equity, Fair Value | 11,585 | 9,793 |
Cash and Cash Equivalents | 11,356 | 9,608 |
Current Marketable Securities | 229 | 185 |
Non-Current Marketable Securities | 0 | 0 |
Level 2 | | |
Debt Securities, Available-for-sale [Line Items] | | |
Marketable Securities, Debt, Adjusted Cost | 174,256 | 162,873 |
Marketable Securities, Debt, Unrealized Gains | 1,055 | 1,742 |
Marketable Securities, Debt, Unrealized Losses | (2,292) | (1,197) |
Marketable Securities, Debt, Fair Value | 173,019 | 163,418 |
Cash and Cash Equivalents | 7,771 | 8,027 |
Current Marketable Securities | 26,565 | 27,514 |
Non-Current Marketable Securities | 138,683 | 127,877 |
Cash | | |
Debt Securities, Available-for-sale [Line Items] | | |
Cash | 17,992 | 17,305 |
Cash and Cash Equivalents | 17,992 | 17,305 |
Current Marketable Securities | 0 | 0 |
Non-Current Marketable Securities | 0 | 0 |
Money market funds | Level 1 | | |
Debt Securities, Available-for-sale [Line Items] | | |
Marketable Securities, Equity, Adjusted Cost | 11,356 | 9,608 |
Marketable Securities, Equity, Unrealized Gains | 0 | 0 |
Marketable Securities, Equity, Unrealized Losses | 0 | 0 |
Marketable Securities, Equity, Fair Value | 11,356 | 9,608 |
Cash and Cash Equivalents | 11,356 | 9,608 |
Current Marketable Securities | 0 | 0 |
Non-Current Marketable Securities | 0 | 0 |
Mutual funds | Level 1 | | |
Debt Securities, Available-for-sale [Line Items] | | |
Marketable Securities, Equity, Adjusted Cost | 215 | 175 |
Marketable Securities, Equity, Unrealized Gains | 16 | 11 |
Marketable Securities, Equity, Unrealized Losses | (2) | (1) |
Marketable Securities, Equity, Fair Value | 229 | 185 |
Cash and Cash Equivalents | 0 | 0 |
Current Marketable Securities | 229 | 185 |
Non-Current Marketable Securities | 0 | 0 |
Equity securities | Level 2 | | |
Debt Securities, Available-for-sale [Line Items] | | |
Marketable Securities, Equity, Adjusted Cost | 1,527 | 1,527 |
Marketable Securities, Equity, Unrealized Gains | 0 | 0 |
Marketable Securities, Equity, Unrealized Losses | (850) | (564) |
Marketable Securities, Equity, Fair Value | 677 | 963 |
Cash and Cash Equivalents | 0 | 0 |
Current Marketable Securities | 677 | 963 |
Non-Current Marketable Securities | 0 | 0 |
U.S. Treasury securities | Level 2 | | |
Debt Securities, Available-for-sale [Line Items] | | |
Marketable Securities, Debt, Adjusted Cost | 29,221 | 22,878 |
Marketable Securities, Debt, Unrealized Gains | 64 | 102 |
Marketable Securities, Debt, Unrealized Losses | (171) | (77) |
Marketable Securities, Debt, Fair Value | 29,114 | 22,903 |
Cash and Cash Equivalents | 3,247 | 3,596 |
Current Marketable Securities | 5,775 | 6,625 |
Non-Current Marketable Securities | 20,092 | 12,682 |
U.S. agency securities | Level 2 | | |
Debt Securities, Available-for-sale [Line Items] | | |
Marketable Securities, Debt, Adjusted Cost | 7,934 | 8,949 |
Marketable Securities, Debt, Unrealized Gains | 1 | 2 |
Marketable Securities, Debt, Unrealized Losses | (116) | (64) |
Marketable Securities, Debt, Fair Value | 7,819 | 8,887 |
Cash and Cash Equivalents | 1,066 | 1,775 |
Current Marketable Securities | 1,581 | 1,930 |
Non-Current Marketable Securities | 5,172 | 5,182 |
Non-U.S. government securities | Level 2 | | |
Debt Securities, Available-for-sale [Line Items] | | |
Marketable Securities, Debt, Adjusted Cost | 18,983 | 20,201 |
Marketable Securities, Debt, Unrealized Gains | 160 | 211 |
Marketable Securities, Debt, Unrealized Losses | (177) | (101) |
Marketable Securities, Debt, Fair Value | 18,966 | 20,311 |
Cash and Cash Equivalents | 200 | 390 |
Current Marketable Securities | 3,279 | 3,091 |
Non-Current Marketable Securities | 15,487 | 16,830 |
Certificates of deposit and time deposits | Level 2 | | |
Debt Securities, Available-for-sale [Line Items] | | |
Marketable Securities, Debt, Adjusted Cost | 3,648 | 1,300 |
Marketable Securities, Debt, Unrealized Gains | 0 | 0 |
Marketable Securities, Debt, Unrealized Losses | 0 | 0 |
Marketable Securities, Debt, Fair Value | 3,648 | 1,300 |
Cash and Cash Equivalents | 2,527 | 490 |
Current Marketable Securities | 1,121 | 810 |
Non-Current Marketable Securities | 0 | 0 |
Commercial paper | Level 2 | | |
Debt Securities, Available-for-sale [Line Items] | | |
Marketable Securities, Debt, Adjusted Cost | 2,261 | 2,639 |
Marketable Securities, Debt, Unrealized Gains | 0 | 0 |
Marketable Securities, Debt, Unrealized Losses | 0 | 0 |
Marketable Securities, Debt, Fair Value | 2,261 | 2,639 |
Cash and Cash Equivalents | 702 | 1,776 |
Current Marketable Securities | 1,559 | 863 |
Non-Current Marketable Securities | 0 | 0 |
Corporate debt securities | Level 2 | | |
Debt Securities, Available-for-sale [Line Items] | | |
Marketable Securities, Debt, Adjusted Cost | 88,617 | 83,883 |
Marketable Securities, Debt, Unrealized Gains | 718 | 1,242 |
Marketable Securities, Debt, Unrealized Losses | (754) | (267) |
Marketable Securities, Debt, Fair Value | 88,581 | 84,858 |
Cash and Cash Equivalents | 29 | 0 |
Current Marketable Securities | 11,665 | 12,327 |
Non-Current Marketable Securities | 76,887 | 72,531 |
Municipal securities | Level 2 | | |
Debt Securities, Available-for-sale [Line Items] | | |
Marketable Securities, Debt, Adjusted Cost | 993 | 967 |
Marketable Securities, Debt, Unrealized Gains | 10 | 14 |
Marketable Securities, Debt, Unrealized Losses | (1) | 0 |
Marketable Securities, Debt, Fair Value | 1,002 | 981 |
Cash and Cash Equivalents | 0 | 0 |
Current Marketable Securities | 150 | 130 |
Non-Current Marketable Securities | 852 | 851 |
Mortgage- and asset-backed securities | Level 2 | | |
Debt Securities, Available-for-sale [Line Items] | | |
Marketable Securities, Debt, Adjusted Cost | 21,072 | 20,529 |
Marketable Securities, Debt, Unrealized Gains | 102 | 171 |
Marketable Securities, Debt, Unrealized Losses | (223) | (124) |
Marketable Securities, Debt, Fair Value | 20,951 | 20,576 |
Cash and Cash Equivalents | 0 | 0 |
Current Marketable Securities | 758 | 775 |
Non-Current Marketable Securities | $ 20,193 | $ 19,801 |