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Marketable and Other Securities - Narrative (Details) - USD ($) $ in Millions | 3 Months Ended |
--- | --- | ---
Mar. 31, 2020 | Mar. 31, 2019 | Dec. 31, 2019
Marketable Securities [Line Items] |  |  |
Sale proceeds from investments classified as available-for-sale and sold prior to maturity | $ 366 | $ 611 |
Lyft, Inc. [Member] | Level 1 [Member] | Other current assets [Member] |  |  |
Marketable Securities [Line Items] |  |  |
Fair value of equity securities |  |  | $ 535
Lyft, Inc. [Member] | Level 3 [Member] | Interest Income and Other Non-Operating Income [Member] |  |  |
Marketable Securities [Line Items] |  |  |
Unrealized gain (loss) on securities |  | $ 285 |

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