Background (Policies)	9 Months Ended
Sep. 30, 2021
Accounting Policies [Abstract]
Basis of presentation	Basis of Presentation Our consolidated balance sheet as of December 31, 2020, which was derived from our audited consolidated financial statements, and our unaudited interim consolidated financial statements provided herein have been prepared in accordance with the instructions for Form 10-Q. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America ("GAAP") have been condensed or omitted pursuant to rules and regulations of the U.S. Securities and Exchange Commission ("SEC"); however, in our opinion, the disclosures made are adequate to make the information presented not misleading. We believe that these consolidated financial statements include all normal recurring adjustments necessary to fairly present the results for the interim periods. The consolidated results of operations and cash flows for the first nine months of the year are not necessarily indicative of the consolidated results of operations and cash flows that might be expected for the entire year. These consolidated financial statements and the accompanying notes should be read in conjunction with the audited consolidated financial statements and the notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2020. The accompanying consolidated financial statements include our accounts and the accounts of our subsidiaries. Intercompany amounts and transactions with our consolidated subsidiaries have been eliminated. Transactions with our non-consolidated affiliates (referred to herein as affiliates) have not been eliminated.
Reclassification	We reclassified certain prior period amounts to conform to the current period presentation, including our revenue by product and service categories.
Segments	SegmentsOur operations are integrated into and reported as part of Lumen Technologies. Lumen's chief operating decision maker ("CODM") is our CODM but reviews our financial information on an aggregate basis only in connection with our quarterly and annual reports that we file with the SEC. Consequently, we do not provide our discrete financial information to the CODM on a regular basis.
Recently adopted and issued accounting pronouncements	Recently Adopted Accounting Pronouncements Debt On January 1, 2021, we adopted ASU 2020-09, "Debt (Topic 470) Amendments to SEC Paragraphs Pursuant to SEC Release No. 33-10762" ("ASU 2020-09"). This ASU amends and supersedes various SEC paragraphs to reflect SEC Release No. 33-10762, which includes amendments to the financial disclosure requirements applicable to registered debt offerings that include credit enhancements, such as subsidiary guarantees. The adoption of ASU 2020-09 did not have an impact to our consolidated financial statements. Investments On January 1, 2021, we adopted ASU 2020-01, "Investments - Equity Securities (Topic 321), Investments - Equity Method and Joint Ventures (Topic 323), and Derivatives and Hedging (Topic 815) - Clarifying the Interactions between Topic 321, Topic 323, and Topic 815)" ("ASU 2020-01"). This ASU, among other things, clarifies that a company should consider observable transactions that require a company to either apply or discontinue the equity method of accounting under Topic 323, Investments - Equity Method and Joint Ventures, for the purposes of applying the measurement alternative in accordance with Topic 321 immediately before applying or upon discontinuing the equity method. As of September 30, 2021, we determined there was no application or discontinuation of the equity method during the reporting periods. The adoption of ASU 2020-01 did not have an impact to our consolidated financial statements. Income Taxes On January 1, 2021, we adopted ASU 2019-12, "Simplifying the Accounting for Income Taxes (Topic 740)" ("ASU 2019-12"). This ASU removes certain exceptions for investments, intra-period allocations and interim calculations, and adds guidance to reduce complexity in accounting for income taxes. The adoption of ASU 2019-12 did not have a material impact to our consolidated financial statements. Measurement of Credit Losses on Financial Instruments We adopted ASU 2016-13, "Measurement of Credit Losses on Financial Instruments" ("ASU 2016-13") on January 1, 2020 and recognized a cumulative adjustment to our accumulated deficit as of the date of adoption of $3 million, net of tax effect of $1 million. Please refer to Note 4—Credit Losses on Financial Instruments for more information. Recently Issued Accounting Pronouncements In March 2020, the FASB issued ASU 2020-04, "Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting" ("ASU 2020-04" or "Reference Rate Reform"), designed to ease the burden of accounting for contract modifications related to the global market-wide reference rate transition period. Subject to certain criteria, ASU 2020-04 provides qualifying entities the option to apply expedients and exceptions to contract modifications and hedging accounting relationships made until December 31, 2022. These amendments are effective immediately and may be applied prospectively to contract modifications made and hedging relationships entered into or evaluated on or before December 31, 2022. ASU 2020-04 provides optional guidance for a limited time to ease the potential burden in accounting for reference rate reform. Based on our review of our key material contracts through September 30, 2021, we do not expect ASU 2020-04 to have any material impact on the consolidated financial statements.
Goodwill and intangible assets, goodwill	We assess our goodwill for impairment annually as of October 31, or, under certain circumstances, more frequently, such as when events or changes in circumstances indicate there may be impairment. We are required to write-down the value of goodwill in periods in which the carrying value of equity exceeds the estimated fair value of equity, limited to the amount of goodwill. Goodwill is evaluated for impairment at the reporting unit level, and we have determined that we have one reporting unit.
Operating lease income	Operating Lease Revenue Qwest leases various data transmission capacity, office facilities, switching facilities and other network sites to third parties under operating leases. Lease and sublease revenue are included in operating revenue in our consolidated statements of operations.
Credit losses on financial instruments	In accordance with ASC 326, "Financial Instruments - Credit Losses," we aggregate financial assets with similar risk characteristics to align our expected credit losses with the credit quality or deterioration over the life of such assets. We monitor certain risk characteristics within our aggregated financial assets and revise their composition accordingly, to the extent internal and external risk factors change each reporting period. Financial assets that do not share risk characteristics with other financial assets are evaluated separately. Our financial assets measured at amortized cost primarily consist of accounts receivable.If there is a deterioration of a customer's financial condition or if future default rates in general differ from currently anticipated default rates (including changes caused by COVID-19), we may need to adjust the allowance for credit losses, which would affect earnings in the period that adjustments are made.

Background (Policies)

9 Months Ended

Sep. 30, 2021

Basis of Presentation

Our consolidated balance sheet as of December 31, 2020, which was derived from our audited consolidated financial statements, and our unaudited interim consolidated financial statements provided herein have been prepared in accordance with the instructions for Form 10-Q. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America ("GAAP") have been condensed or omitted pursuant to rules and regulations of the U.S. Securities and Exchange Commission ("SEC"); however, in our opinion, the disclosures made are adequate to make the information presented not misleading. We believe that these consolidated financial statements include all normal recurring adjustments necessary to fairly present the results for the interim periods. The consolidated results of operations and cash flows for the first nine months of the year are not necessarily indicative of the consolidated results of operations and cash flows that might be expected for the entire year. These consolidated financial statements and the accompanying notes should be read in conjunction with the audited consolidated financial statements and the notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2020.

The accompanying consolidated financial statements include our accounts and the accounts of our subsidiaries. Intercompany amounts and transactions with our consolidated subsidiaries have been eliminated. Transactions with our non-consolidated affiliates (referred to herein as affiliates) have not been eliminated.

Reclassification

We reclassified certain prior period amounts to conform to the current period presentation, including our revenue by product and service categories.

Segments

SegmentsOur operations are integrated into and reported as part of Lumen Technologies. Lumen's chief operating decision maker ("CODM") is our CODM but reviews our financial information on an aggregate basis only in connection with our quarterly and annual reports that we file with the SEC. Consequently, we do not provide our discrete financial information to the CODM on a regular basis.

Recently adopted and issued accounting pronouncements

Recently Adopted Accounting Pronouncements

Debt

On January 1, 2021, we adopted ASU 2020-09, "Debt (Topic 470) Amendments to SEC Paragraphs Pursuant to SEC Release No. 33-10762" ("ASU 2020-09"). This ASU amends and supersedes various SEC paragraphs to reflect SEC Release No. 33-10762, which includes amendments to the financial disclosure requirements applicable to registered debt offerings that include credit enhancements, such as subsidiary guarantees. The adoption of ASU 2020-09 did not have an impact to our consolidated financial statements.

Investments

On January 1, 2021, we adopted ASU 2020-01, "Investments - Equity Securities (Topic 321), Investments - Equity Method and Joint Ventures (Topic 323), and Derivatives and Hedging (Topic 815) - Clarifying the Interactions between Topic 321, Topic 323, and Topic 815)" ("ASU 2020-01"). This ASU, among other things, clarifies that a company should consider observable transactions that require a company to either apply or discontinue the equity method of accounting under Topic 323, Investments - Equity Method and Joint Ventures, for the purposes of applying the measurement alternative in accordance with Topic 321 immediately before applying or upon discontinuing the equity method. As of September 30, 2021, we determined there was no application or discontinuation of the equity method during the reporting periods. The adoption of ASU 2020-01 did not have an impact to our consolidated financial statements.

Income Taxes

On January 1, 2021, we adopted ASU 2019-12, "Simplifying the Accounting for Income Taxes (Topic 740)" ("ASU 2019-12"). This ASU removes certain exceptions for investments, intra-period allocations and interim calculations, and adds guidance to reduce complexity in accounting for income taxes. The adoption of ASU 2019-12 did not have a material impact to our consolidated financial statements.

Measurement of Credit Losses on Financial Instruments

We adopted ASU 2016-13, "Measurement of Credit Losses on Financial Instruments" ("ASU 2016-13") on January 1, 2020 and recognized a cumulative adjustment to our accumulated deficit as of the date of adoption of $3 million, net of tax effect of $1 million. Please refer to Note 4—Credit Losses on Financial Instruments for more information.

Recently Issued Accounting Pronouncements

In March 2020, the FASB issued ASU 2020-04, "Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting" ("ASU 2020-04" or "Reference Rate Reform"), designed to ease the burden of accounting for contract modifications related to the global market-wide reference rate transition period. Subject to certain criteria, ASU 2020-04 provides qualifying entities the option to apply expedients and exceptions to contract modifications and hedging accounting relationships made until December 31, 2022. These amendments are effective immediately and may be applied prospectively to contract modifications made and hedging relationships entered into or evaluated on or before December 31, 2022. ASU 2020-04 provides optional guidance for a limited time to ease the potential burden in accounting for reference rate reform. Based on our review of our key material contracts through September 30, 2021, we do not expect ASU 2020-04 to have any material impact on the consolidated financial statements.

Goodwill and intangible assets, goodwill

We assess our goodwill for impairment annually as of October 31, or, under certain circumstances, more frequently, such as when events or changes in circumstances indicate there may be impairment. We are required to write-down the value of goodwill in periods in which the carrying value of equity exceeds the estimated fair value of equity, limited to the amount of goodwill. Goodwill is evaluated for impairment at the reporting unit level, and we have determined that we have one reporting unit.

Operating lease income

Operating Lease Revenue

Qwest leases various data transmission capacity, office facilities, switching facilities and other network sites to third parties under operating leases. Lease and sublease revenue are included in operating revenue in our consolidated statements of operations.

Credit losses on financial instruments

In accordance with ASC 326, "Financial Instruments - Credit Losses," we aggregate financial assets with similar risk characteristics to align our expected credit losses with the credit quality or deterioration over the life of such assets. We monitor certain risk characteristics within our aggregated financial assets and revise their composition accordingly, to the extent internal and external risk factors change each reporting period. Financial assets that do not share risk characteristics with other financial assets are evaluated separately. Our financial assets measured at amortized cost primarily consist of accounts receivable.If there is a deterioration of a customer's financial condition or if future default rates in general differ from currently anticipated default rates (including changes caused by COVID-19), we may need to adjust the allowance for credit losses, which would affect earnings in the period that adjustments are made.