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v3.25.0.1

Divestitures of the Latin American, ILEC and EMEA Businesses (Details) |  |  |  |  |  | 3 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | --- | --- | --- | ---
Nov. 01, 2023 USD ($) | Oct. 31, 2023 USD ($) | Oct. 31, 2022 USD ($) | Oct. 03, 2022 USD ($) state | Aug. 01, 2022 USD ($) | Dec. 31, 2024 USD ($) state | Jun. 30, 2023 USD ($) | Mar. 31, 2023 USD ($) | Dec. 31, 2022 USD ($) | Dec. 31, 2024 USD ($) state | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($) | Jul. 25, 2021 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Gain (loss) on disposal groups held for sale |  |  |  |  |  |  |  |  |  | $ 0 | $ 0 | $ (40,000,000) |
Goodwill |  |  |  |  |  | $ 1,964,000,000 |  |  | $ 12,657,000,000 | 1,964,000,000 | 1,964,000,000 | 12,657,000,000 |
Reclassification of realized loss on foreign currency translation | $ 382,000,000 |  |  |  | $ 112,000,000 |  |  |  |  | 0 | 382,000,000 | 112,000,000 |
Goodwill impairment |  | $ 1,900,000,000 |  |  |  | $ 0 | $ 8,800,000,000 |  |  | $ 0 | 10,693,000,000 | 3,271,000,000 |
Purchaser of ILEC |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Purchase obligation |  |  |  | $ 373,000,000 |  |  |  |  |  |  |  |  |
Purchase obligation period (in years) |  |  |  | 3 years |  |  |  |  |  |  |  |  |
Payments for purchase of services |  |  |  |  |  |  |  | $ 89,000,000 |  |  |  |  |
Pension Plans |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Reclassified of net actuarial loss and prior service credit, net of tax |  |  |  | $ 403,000,000 |  |  |  |  |  |  |  |  |
Purchaser of ILEC |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Purchase obligation |  |  |  | $ 67,000,000 |  |  |  |  |  |  |  |  |
Purchase obligation period (in years) |  |  |  | 3 years |  |  |  |  |  |  |  |  |
ILEC Business |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Number of states in which the business is conducted | state |  |  |  |  |  | 17 |  |  |  | 17 |  |  |
Disposal Group, Held-for-sale, Not Discontinued Operations | Latin American Business | Level 3 Parent, LLC |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Cash consideration from disposal of business |  |  |  |  |  |  |  |  |  |  |  |  | $ 2,700,000,000
Disposal Group, Held-for-sale, Not Discontinued Operations | ILEC Business |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Cash consideration from disposal of business |  |  |  | $ 7,500,000,000 |  |  |  |  |  |  |  |  |
Long term debt, net of discounts |  |  |  | 1,500,000,000 |  |  |  |  |  |  |  |  |
Disposal Group, Held-for-sale, Not Discontinued Operations | EMEA Business |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Goodwill impairment |  |  | $ 43,000,000 |  |  |  |  |  |  |  |  |  |
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Latin American Business |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Gain (loss) on disposal groups held for sale |  |  |  |  |  |  |  |  |  |  |  | 597,000,000 |
Indemnifications related to the sale of businesses |  |  |  |  |  |  |  |  | 86,000,000 |  |  | 86,000,000 |
Net assets |  |  |  |  | 1,900,000,000 |  |  |  |  |  |  |  |
Property, plant and equipment, net accumulated depreciation |  |  |  |  | 1,700,000,000 |  |  |  |  |  |  |  |
Goodwill |  |  |  |  | 245,000,000 |  |  |  |  |  |  |  |
Accumulated amortization |  |  |  |  | 140,000,000 |  |  |  |  |  |  |  |
Deferred income tax liabilities |  |  |  |  | $ 154,000,000 |  |  |  |  |  |  |  |
Disposal Group, Disposed of by Sale, Not Discontinued Operations | ILEC Business |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Gain (loss) on disposal groups held for sale |  |  |  |  |  |  |  |  |  |  |  | 176,000,000 |
Indemnifications related to the sale of businesses |  |  |  |  |  |  |  |  | 89,000,000 |  |  | 89,000,000 |
Net assets |  |  |  | 4,800,000,000 |  |  |  |  |  |  |  |  |
Property, plant and equipment, net accumulated depreciation |  |  |  | 3,600,000,000 |  |  |  |  |  |  |  |  |
Goodwill |  |  |  | $ 2,600,000,000 |  |  |  |  |  |  |  |  |
Number of states in which the business is conducted | state |  |  |  | 20 |  |  |  |  |  |  |  |  |
Consideration after closing adjustments |  |  |  | $ 400,000,000 |  |  |  |  |  |  |  |  |
Long term debt, net of discounts |  |  |  | 1,400,000,000 |  |  |  |  |  |  |  |  |
Net proceeds from sales of colocation business and data centers |  |  |  | $ 5,600,000,000 |  |  |  |  |  |  |  |  |
Disposal Group, Disposed of by Sale, Not Discontinued Operations | EMEA Business |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Gain (loss) on disposal groups held for sale |  |  |  |  |  |  |  |  |  |  | $ (102,000,000) | $ (660,000,000) |
Net assets | 2,100,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Property, plant and equipment, net accumulated depreciation | 2,000,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Accumulated amortization | 107,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Goodwill impairment |  |  |  |  |  |  |  |  | $ 43,000,000 |  |  |  |
Disposal Group, Disposed of by Sale, Not Discontinued Operations | EMEA Business | Level 3 Parent, LLC |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Cash consideration from disposal of business | $ 1,700,000,000 |  |  |  |  |  |  |  |  |  |  |  |

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- Definition Minimum amount of purchase arrangement in which the entity has agreed to expend funds to procure goods or services from a supplier. + References No definition available. + Details
Name: | us-gaap_PurchaseObligation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | srt_CounterpartyNameAxis=lumn_PurchaserOfILECMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=lumn_PurchaserOfILECMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsegmentsAxis=lumn_ILECBusinessMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DisposalGroupClassificationAxis=us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=lumn_LatinAmericanBusinessMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=lumn_Level3ParentLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=lumn_ILECBusinessMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=lumn_EMEABusinessMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DisposalGroupClassificationAxis=us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |