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Intangible Assets - Schedules (Details) - Licenses - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017
Indefinite-lived Intangible Assets [Line Items] |  |
Balance at beginning of year | $ 2,223 | $ 1,886
Acquisitions | 8 | 331
Transferred to Assets held for sale | (51) | (10)
Divestitures | (11) | 0
Exchanges - Licenses received | 18 | 25
Exchanges - Licenses surrendered | (1) | (9)
Balance at end of year | $ 2,186 | $ 2,223

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- Definition The increase (decrease) during the period in book value of long-lived assets that the reporting entity plans to sell within one year (or one business cycle). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 + 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 Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
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- Details
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