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Short-Term Deposits and Marketable Securities - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable Recorded Investment [Line Items]
Short-term deposits	$ 581,000,000	$ 4,000,000
Marketable securities	133,000,000	133,000,000	$ 330,000,000
Proceeds from matured marketable securities		200,000,000	100,000,000
Investment of available cash in short-term deposits	581,000,000
Debt securities, allowance recognized	0
U.S. Treasury Debt Securities [Member]
Financing Receivable Recorded Investment [Line Items]
Marketable securities	$ 133,000,000	133,000,000	$ 330,000,000
Proceeds from matured marketable securities		$ 200,000,000
Weighted average maturity period	6 months
Aggregate amortized cost basis of securities	$ 132,000,000

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Short-term deposits.

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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).

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Amount of allowance for credit loss 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 of investment in marketable security, classified as current.

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The cash outflow for securities or other assets acquired, which qualify for treatment as an investing activity and are to be liquidated, if necessary, within the current operating cycle. Includes cash flows from securities classified as trading securities that were acquired for reasons other than sale in the short-term.

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