Number of shares of common stock outstanding increase percentage.

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Share-based compensation arrangement by share-based payment award, options, grants in period, vest percentage per annum.

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Share-based Compensation Arrangement by Share-based Payment Award, Purchase Offering Period

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Share-based compensation arrangement by share-based payment award, requisite service period begins and continue to vest, employment continuation period.

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Share-based Compensation Arrangement By Share-based Payment Award, Equity Instruments Other Than Options, Grants in Period, Performance Target, Percentage

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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Amount of cost to be recognized for option under share-based payment arrangement.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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Purchase price of common stock expressed as a percentage of its fair value.

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Equity Awards - Additional Information (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2021 USD ($) plan shares	Sep. 30, 2020 USD ($)	Jun. 30, 2021 shares	Mar. 31, 2021 shares	Dec. 31, 2020 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity incentive plans \| plan	3
Fair value of stock options vested	$ 6
Total unrecognized compensation cost, adjusted for estimated forfeitures, related to unvested stock options	$ 21
Options outstanding
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining weighted-average period	3 years
Restricted stock units with service condition only
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding (in shares) \| shares	6,200,000
Restricted stock units with service and performance conditions
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares outstanding (in shares) \| shares	300,000
Performance-based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares eligible to vest (percent)	100.00%
Stock-based compensation expense, net of actual and estimated forfeitures	$ 88	$ 41
Performance-based RSUs \| Vesting, tranche one
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting term	2 years
Performance-based RSUs \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares eligible to vest (percent)	0.00%
Performance-based RSUs \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares eligible to vest (percent)	200.00%
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining weighted-average period	3 years
Number of shares outstanding (in shares) \| shares	6,527,000		7,305,000	8,047,000	7,362,000
Unrecognized compensation expense expected to be recognized	$ 2,000
2012 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock purchase price percentage	85.00%
Award offering period	6 months
Number of shares of common stock outstanding, increase, percentage	1.00%
2005 and 2012 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted to new employees vest, percentage per annum	25.00%
Requisite service period to vest employment continuation period	3 years
Options granted, exercisable period	10 years