| Acquisition - Pro Forma Information (Details) - Pandora - USD ($) $ in Millions | 3 Months Ended | |
|---|---|---|
| Mar. 31, 2019 | Mar. 31, 2018 | |
| Business Acquisition [Line Items] | ||
| Revenue | $ 251 | |
| Net income | 122 | |
| Total revenue | 1,860 | $ 1,697 | 
| Net income | $ 181 | $ 172 | 
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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. No definition available. 
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- Definition The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition This element represents the amount of earnings or loss of the acquiree since the acquisition date included in the consolidated income statement for the reporting period. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition This element represents the amount of revenue of the acquiree since the acquisition date included in the consolidated income statement for the reporting period. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Details 
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