Financial Instruments (Carrying Amount of Equity Securities) (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | |||
|---|---|---|---|---|---|
Jun. 30, 2021 |
Jun. 30, 2020 |
Jun. 30, 2021 |
Jun. 30, 2020 |
Dec. 31, 2020 |
|
| Debt and Equity Securities, FV-NI [Line Items] | |||||
| Total sale price | $ 2,629 | $ 590 | $ 3,353 | $ 1,499 | |
| Total initial cost | 409 | 424 | 766 | 685 | |
| Cumulative net gains | (2,220) | $ (166) | (2,587) | $ (814) | |
| Marketable Securities | |||||
| Total initial cost | 2,662 | 2,662 | $ 2,227 | ||
| Cumulative net gain (loss) | 4,208 | 4,208 | 3,631 | ||
| Carrying value | 6,870 | 6,870 | 5,858 | ||
| Non-Marketable Securities | |||||
| Total initial cost | 14,743 | 14,743 | 14,616 | ||
| Cumulative net gain (loss) | 8,730 | 8,730 | 4,277 | ||
| Carrying value | 23,473 | 23,473 | 18,893 | ||
| Total | |||||
| Total initial cost | 17,405 | 17,405 | 16,843 | ||
| Cumulative net gain (loss) | 12,938 | 12,938 | 7,908 | ||
| Carrying value | 30,343 | 30,343 | 24,751 | ||
| Cumulative loss from equity derivatives | 684 | ||||
| Cumulative net gain of non-marketable securities | 10,400 | 10,400 | 6,100 | ||
| Unrealized loss of non-marketable securities | 1,700 | 1,700 | 1,900 | ||
| Other Noncurrent Assets | |||||
| Marketable Securities | |||||
| Carrying value | $ 591 | $ 591 | $ 429 | ||