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Marketable and Other Securities - Narrative (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2020 | Sep. 30, 2019
Marketable Securities [Line Items] |  |  |  |
Sale proceeds from investments classified as available-for-sale and sold prior to maturity | $ 476 | $ 535 | $ 1,400 | $ 1,600
Lyft, Inc. [Member] | Interest Income and Other Non-Operating Income [Member] | Other current assets [Member] |  |  |  |
Marketable Securities [Line Items] |  |  |  |
Unrealized gain (loss) on securities |  | $ (291) |  | $ (71)

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