Financial Instruments Financial Instruments - Investments - Unrealized Gains and Losses Related to Equity Securities - Footnotes (Details) $ in Millions |
Sep. 27, 2020
USD ($)
|
|---|---|
| Fair Value Disclosures [Abstract] | |
| Cumulative impairment losses and downward price adjustments on equity securities | $ 82 |
| Cumulative upward price adjustments on equity securities | $ 63 |