Background (Policies)	9 Months Ended
Background (Policies)	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation Our consolidated balance sheet as of December 31, 2019, 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 SEC. However, in our opinion, the disclosures made therein 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, 2019. The accompanying consolidated financial statements include our accounts and the accounts of our subsidiaries in which we have a controlling interest. Intercompany amounts and transactions with our consolidated subsidiaries have been eliminated. To simplify the overall presentation of our consolidated financial statements, we report immaterial amounts attributable to noncontrolling interests in certain of our subsidiaries as follows: (i) income attributable to noncontrolling interests in other loss, net, (ii) equity attributable to noncontrolling interests in additional paid-in capital and (iii) cash flows attributable to noncontrolling interests in other, net, financing activities.
Reclassification	We reclassified certain prior period amounts to conform to the current period presentation, including the categorization of our revenue and expenses in our segment reporting. See Note 11—Segment Information for additional information. These changes had no impact on total operating revenue, total operating expenses or net income (loss) for any period.
Operating Leases	Operating lease assets are included in Other, net under goodwill and other assets on our consolidated balance sheets. Noncurrent operating lease liabilities are included in Other under deferred credits and other liabilities on our consolidated balance sheets.
Operating Lease Income	Operating Lease Income Lumen Technologies leases various dark fiber, office facilities, switching facilities and other network sites to third parties under operating leases. Lease and sublease income are included in operating revenue in our consolidated statements of operations.
Recently Adopted and Issued Accounting Pronouncements	Recently Adopted Accounting Pronouncements In June 2016, the Financial Accounting Standards Board ("FASB") issued ASU 2016-13, "Measurement of Credit Losses on Financial Instruments" ("ASU 2016-13"). The primary impact of ASU 2016-13 for us is a change in the model for the recognition of credit losses related to our financial instruments from an incurred loss model, which recognized credit losses only if it was probable that a loss had been incurred, to an expected loss model, which requires us to estimate the total credit losses expected on the portfolio of financial instruments. We adopted ASU 2016-13 on January 1, 2020, and recognized a cumulative adjustment to our accumulated deficit as of the date of adoption of $9 million, net of tax effect. Please refer to Note 4—Credit Losses on Financial Instruments for more information. Recently Issued Accounting Pronouncements In December 2019, the FASB issued ASU 2019-12, "Simplifying the Accounting for Income Taxes (Topic 740)" ("ASU 2019-12"). ASU 2019-12 removes certain exceptions for investments, intra-period allocations and interim calculations, and adds guidance to reduce complexity in accounting for income taxes. ASU 2019-12 will become effective for us in the first quarter of fiscal 2021 and early adoption is permitted. We do not believe the adoption will have a significant impact on our consolidated financial statements. 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"), 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. We are evaluating ASU 2020-04's applicability to relevant transactions referencing the London Inter-bank Offering Rate ("LIBOR") or another reference rate expected to be discontinued and the resulting impact on our consolidated financial statements.