Financial Instruments (Measurement Alternative Investments) (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Equity Securities, FV-NI, Gain (Loss), Alternative [Abstract] | |||
| Net gain (loss) on equity securities sold during the period | $ (301) | $ 1,458 | |
| Unrealized gain (loss) on equity securities held as of the end of the period | 2,950 | 4,002 | |
| Total gain (loss) recognized in other income (expense), net | 2,649 | 5,460 | $ 73 |
| Total unrealized gain (loss) for non-marketable equity securities | $ 1,791 | $ 4,107 | |