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Equity-Based Compensation (Detail) $ in Millions | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2020 USD ($) item shares | Dec. 31, 2019 USD ($) shares | Dec. 31, 2018 USD ($) shares | Feb. 01, 2021 shares | May 31, 2014 shares
2014 Stock Incentive Plan [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Shares available under employee stock plans | 18,000,000.0 |  |  |  |
Maximum number of shares authorized for issuance |  |  |  |  | 23,800,000
2009 Stock Incentive Plan [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Shares available under employee stock plans |  |  |  |  | 1,100,000
Employee Stock Purchase Plan [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Service period | 30 days |  |  |  |
Number of offering periods | item | 2 |  |  |  |
Price employees purchase shares (as a percent) | 85.00% |  |  |  |
Annual salary deducted for plan (as a percent) | 10.00% |  |  |  |
Shares issued under the plan | 570,000 | 537,000 | 582,000 |  |
Shares available under employee stock plans |  |  |  | 3,200,000 |
Additional shares authorized (in shares) | 3,000,000.0 |  |  |  |
Compensation expense recognized | $ | $ 13 | $ 10 | $ 9 |  |
Compensation expense recognized, net of tax | $ | $ 10 | $ 7 | $ 7 |  |

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- Definition Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition 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. + References No definition available. + Details
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- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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