Goodwill, Spectrum License Transactions and Other Intangible Assets - Schedule of Changes in Carrying Amount of Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Historical goodwill		$ 12,449
Goodwill from acquisition	$ 29
Accumulated impairment losses	(10,766)	(10,766)
December 31, 2018	1,901
December 31, 2019	$ 1,930	1,901
Layer3 TV
Goodwill [Roll Forward]
Goodwill from acquisition		$ 218

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount before accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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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.

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