| Goodwill - Additional Information (Details) | 3 Months Ended | |
|---|---|---|
| Mar. 31, 2017  USD ($)  segment | Mar. 31, 2016  USD ($) | |
| Goodwill and Intangible Assets Disclosure [Abstract] | ||
| Number of reportable segments | segment | 1 | |
| Impairment losses for goodwill | $ 0 | $ 0 | 
| Accumulated impairment of goodwill since the Merger | $ 4,766,190,000 | |
| X | ||||||||||
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- References No definition available. 
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| X | ||||||||||
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- Definition Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements. No definition available. 
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