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v3.20.2

Basis of Presentation - Narrative (Details) | Sep. 30, 2020
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UScellular |
Basis of Presentation [Line Items] |
TDS ownership of UScellular | 82.00%

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- Definition Used to group disclosures related to significant accounting policies. + References No definition available. + Details
Name: | tds_BasisOfPresentationLineItems
Namespace Prefix: | tds_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Definition The parent entity's interest in net assets of the subsidiary, expressed as a percentage. + References No definition available. + Details
Name: | us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

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- Details
Name: | srt_OwnershipAxis=tds_UnitedStatesCellularCorporationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |