Investments (Equity Investments Without Readily Determinable Fair Values Assessed Under the Measurement Alternative) (Details) - USD ($) $ in Millions |
3 Months Ended | |
---|---|---|
Mar. 31, 2020 |
Dec. 31, 2019 |
|
Other Investment Not Readily Marketable [Line Items] | ||
Equity investments without readily determinable fair values: | $ 520 | $ 514 |
Various Equity Investments Without Readily Determinable Fair Values | ||
Other Investment Not Readily Marketable [Line Items] | ||
Equity investments without readily determinable fair values: | 6 | |
Equity securities without readily determinable fair value, increase (decrease) | $ 9 |