Goodwill, Spectrum License Transactions and Other Intangible Assets - Spectrum Licenses (Details) - Licensing Agreements $ in Millions	6 Months Ended
Jun. 30, 2021 USD ($)
Indefinite-lived Intangible Assets [Roll Forward]
Beginning balance	$ 82,828
Spectrum license acquisitions	87
Costs to clear spectrum	2
Ending balance	$ 82,917

Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.

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

Name:	us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant