Investments and Fair Value Measurement - Summary of Amortized Cost, Unrealized Gains and Losses of Financial Assets (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 2,281	$ 2,281
Recurring
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	3,223	3,756
Unrealized Gains	1,311	61
Unrealized Losses	0	0
Fair Value	4,534	3,817
Recurring \| Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	440	611
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	440	611
Recurring \| U.S. government and agency securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	322	542
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	322	542
Recurring \| Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	180	322
Unrealized Gains	1	1
Unrealized Losses	0	0
Fair Value	181	323
Recurring \| Non-marketable debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,281	2,281
Unrealized Gains	1,310	60
Unrealized Losses	0	0
Fair Value	$ 3,591	$ 2,341

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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