Background (Policies)	3 Months Ended
Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Consolidation policy	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 income (expense), 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 policy	We reclassified certain prior period amounts to conform to the current period presentation, including the categorization of our revenues and our segment reporting. See Note 10—Segment Information for additional information. These changes had no impact on total operating revenues, total operating expenses or net income for any period.
Recently adopted accounting pronouncements and recent accounting pronouncements	Recently Adopted Accounting Pronouncements In the first quarter of 2018, we adopted Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers”, ASU 2016-16, “Intra-Entity Transfers of Assets Other Than Inventory”, and ASU 2018-02, “Income Statement-Reporting Comprehensive Income: Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income”. Each of these is described further below. Revenue Recognition ASU 2014-09 ("ASC 606") replaces virtually all existing GAAP on revenue recognition with a principles-based approach for determining revenue recognition using a new five step model. We adopted the new revenue recognition standard under the modified retrospective transition method and recorded a cumulative catch-up as of January 1, 2018, which resulted in an increase to retained earnings of $297 million. Upon adoption, we deferred (or capitalized) incremental customer contract acquisition costs and plan to recognize such costs over the average customer life, which approximates the initial contract term and anticipated renewals for contracts to which such costs relate. Our deferred contract costs for our business and consumer customers have average amortization periods of approximately 49 months and 30 months, respectively, and are subject to being monitored every period to reflect any significant change in assumptions. In addition, we intend to assess our deferred contract cost asset for impairment on a periodic basis. Promotional bill credits, discounts and prepaid cards offered to customers as part of renewing services or entering into a new services arrangement that are paid over time and are contingent on the customer maintaining a service contract results in an extended service contract term with multiple performance obligations, which impacts the allocation and timing of revenue recognition between service revenue and revenue assigned to the customer credits. The contract asset is subsequently amortized as a reduction to service revenue over the extended contract term. Most of our indefeasible right of use arrangements, including certain long-term prepaid customer capacity arrangements, are accounted for as operating leases. See Note 4—Revenue Recognition for additional information. Comprehensive Income ASU 2018-02 provides an option to reclassify stranded tax effects within accumulated other comprehensive income to retained earnings in each period in which the effect of the change in the U.S. federal corporate income tax rate in the Tax Cuts and Jobs Act (or portion thereof) is recorded. If an entity elects to reclassify the income tax effects of the Tax Cuts and Jobs Act, the amount of that reclassification shall include the effect of the change in the U.S. federal corporate income tax rate on the gross deferred tax amounts and related valuation allowances, if any, at the date of enactment of the Tax Cuts and Jobs Act related to items remaining in accumulated other comprehensive income. The effect of the change in the U.S. federal corporate income tax rate on gross valuation allowances that were originally charged to income from continuing operations shall not be included. ASU 2018-02 is effective January 1, 2019, but early adoption is permitted and should be applied either in the period of adoption or retrospectively to each period (or periods) in which the effect of the change in the U.S. federal corporate income tax rate in the Tax Cuts and Jobs Act is recognized. We early adopted and applied ASU 2018-02 in the first quarter of 2018. The adoption of ASU 2018-02 resulted in a $407 million increase to retained earnings and in accumulated other comprehensive loss. See Note 13—Accumulated Other Comprehensive Loss for additional information. Income Taxes ASU 2016-16 eliminates the current prohibition on the recognition of the income tax effects on the transfer of assets among our subsidiaries. Prospectively, the income tax effects associated with these asset transfers, except for the transfer of inventory, will be recognized in the period the asset is transferred versus the current deferral and recognition upon either the sale of the asset to a third party or over the remaining useful life of the asset. Our adoption of ASU 2016-16 did not have a material impact to our consolidated financial statements. Recent Accounting Pronouncements Goodwill Impairment On January 26, 2017, the FASB issued ASU 2017-04, “Simplifying the Test for Goodwill Impairment” (“ASU 2017-04”). ASU 2017-04 simplifies the impairment testing for goodwill by changing the measurement for goodwill impairment. Under current rules, we are required to compute the implied fair value of goodwill to measure the impairment amount if the carrying value of a reporting unit exceeds its fair value. Under ASU 2017-04, the goodwill impairment charge will equal the excess of the reporting unit carrying value above its fair value, limited to the amount of goodwill assigned to the reporting unit. We are required to adopt the provisions of ASU 2017-04 for any goodwill impairment tests, including our required annual test, occurring after January 1, 2020, but have the option to early adopt it for any impairment test that we are required to perform. We have not determined if we will elect to early adopt the provisions of ASU 2017-04. The provisions of ASU 2017-04 would not have affected our last goodwill impairment assessment, but no assurance can be provided that the simplified testing methodology will not affect our goodwill impairment assessment in the future. Financial Instruments On June 16, 2016, the 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 our management team to estimate the total credit losses expected on the portfolio of financial instruments. We are currently reviewing the requirements of the standard and evaluating the impact on our consolidated financial statements. We are required to adopt the provisions of ASU 2016-13 effective January 1, 2020, but could elect to early adopt the provisions as of January 1, 2019. We expect to recognize the impacts of adopting ASU 2016-13 through a cumulative adjustment to retained earnings as of the date of adoption. As of the date of this report, we have not yet determined the date we will adopt ASU 2016-13. Leases On February 25, 2016, the FASB issued ASU 2016-02, “Leases” (“ASU 2016-02”). The core principle of ASU 2016-02 will require lessees to present right-of-use assets and lease liabilities on their balance sheets for operating leases, which under GAAP are currently not required to be reflected on their balance sheets. ASU 2016-02 is effective for annual and interim periods beginning January 1, 2019. Early adoption of ASU 2016-02 is permitted. Upon adoption of ASU 2016-02, we are required to recognize and measure leases at the beginning of the earliest period presented in our consolidated financial statements using a modified retrospective approach. The modified retrospective approach includes a number of optional practical expedients that we may elect to apply. On January 25, 2018, the FASB issued ASU 2018-01, “Leases: Land Easement Practical Expedient for Transition to ASU 2016-02. ASU 2018-01 permits reporting companies to elect to forego reassessments of land easements that exist or expire before the entity’s adoption of ASU 2016-02 and that were not previously accounted for as leases. We plan to adopt ASU 2018-01 at the same time we adopt ASU 2016-02. We are in the process of implementing a new lease administration and accounting system. We plan to adopt ASU 2016-02 and ASU 2018-01 effective January 1, 2019. The adoption of ASU 2016-02 will result in our recognition of right of use assets and lease liabilities that we have not previously recorded. Although we believe it is premature as of the date of this report to provide any estimate of the impact of adopting ASU 2016-02, we do expect that it will have a material impact on our consolidated financial statements. Additionally, upon implementing ASU 2016-02, accounting for the failed-sale-leaseback transaction described in Note 3—Sale of Data Centers and Colocation Business will no longer be applicable based on our facts and circumstances, and the real estate assets and corresponding financing obligation described therein will be derecognized from our consolidated balance sheet.

Recently Adopted Accounting Pronouncements

In the first quarter of 2018, we adopted Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers”, ASU 2016-16, “Intra-Entity Transfers of Assets Other Than Inventory”, and ASU 2018-02, “Income Statement-Reporting Comprehensive Income: Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income”.

Each of these is described further below.

Revenue Recognition

ASU 2014-09 ("ASC 606") replaces virtually all existing GAAP on revenue recognition with a principles-based approach for determining revenue recognition using a new five step model.

We adopted the new revenue recognition standard under the modified retrospective transition method and recorded a cumulative catch-up as of January 1, 2018, which resulted in an increase to retained earnings of $297 million.

Upon adoption, we deferred (or capitalized) incremental customer contract acquisition costs and plan to recognize such costs over the average customer life, which approximates the initial contract term and anticipated renewals for contracts to which such costs relate. Our deferred contract costs for our business and consumer customers have average amortization periods of approximately 49 months and 30 months, respectively, and are subject to being monitored every period to reflect any significant change in assumptions. In addition, we intend to assess our deferred contract cost asset for impairment on a periodic basis.

Promotional bill credits, discounts and prepaid cards offered to customers as part of renewing services or entering into a new services arrangement that are paid over time and are contingent on the customer maintaining a service contract results in an extended service contract term with multiple performance obligations, which impacts the allocation and timing of revenue recognition between service revenue and revenue assigned to the customer credits. The contract asset is subsequently amortized as a reduction to service revenue over the extended contract term.

Most of our indefeasible right of use arrangements, including certain long-term prepaid customer capacity arrangements, are accounted for as operating leases.

See Note 4—Revenue Recognition for additional information.

Comprehensive Income

ASU 2018-02 provides an option to reclassify stranded tax effects within accumulated other comprehensive income to retained earnings in each period in which the effect of the change in the U.S. federal corporate income tax rate in the Tax Cuts and Jobs Act (or portion thereof) is recorded. If an entity elects to reclassify the income tax effects of the Tax Cuts and Jobs Act, the amount of that reclassification shall include the effect of the change in the U.S. federal corporate income tax rate on the gross deferred tax amounts and related valuation allowances, if any, at the date of enactment of the Tax Cuts and Jobs Act related to items remaining in accumulated other comprehensive income. The effect of the change in the U.S. federal corporate income tax rate on gross valuation allowances that were originally charged to income from continuing operations shall not be included. ASU 2018-02 is effective January 1, 2019, but early adoption is permitted and should be applied either in the period of adoption or retrospectively to each period (or periods) in which the effect of the change in the U.S. federal corporate income tax rate in the Tax Cuts and Jobs Act is recognized. We early adopted and applied ASU 2018-02 in the first quarter of 2018. The adoption of ASU 2018-02 resulted in a $407 million increase to retained earnings and in accumulated other comprehensive loss. See Note 13—Accumulated Other Comprehensive Loss for additional information.

Income Taxes

ASU 2016-16 eliminates the current prohibition on the recognition of the income tax effects on the transfer of assets among our subsidiaries. Prospectively, the income tax effects associated with these asset transfers, except for the transfer of inventory, will be recognized in the period the asset is transferred versus the current deferral and recognition upon either the sale of the asset to a third party or over the remaining useful life of the asset. Our adoption of ASU 2016-16 did not have a material impact to our consolidated financial statements.

Recent Accounting Pronouncements

Goodwill Impairment

On January 26, 2017, the FASB issued ASU 2017-04, “Simplifying the Test for Goodwill Impairment” (“ASU 2017-04”). ASU 2017-04 simplifies the impairment testing for goodwill by changing the measurement for goodwill impairment. Under current rules, we are required to compute the implied fair value of goodwill to measure the impairment amount if the carrying value of a reporting unit exceeds its fair value. Under ASU 2017-04, the goodwill impairment charge will equal the excess of the reporting unit carrying value above its fair value, limited to the amount of goodwill assigned to the reporting unit.

We are required to adopt the provisions of ASU 2017-04 for any goodwill impairment tests, including our required annual test, occurring after January 1, 2020, but have the option to early adopt it for any impairment test that we are required to perform. We have not determined if we will elect to early adopt the provisions of ASU 2017-04. The provisions of ASU 2017-04 would not have affected our last goodwill impairment assessment, but no assurance can be provided that the simplified testing methodology will not affect our goodwill impairment assessment in the future.

Financial Instruments

On June 16, 2016, the 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 our management team to estimate the total credit losses expected on the portfolio of financial instruments. We are currently reviewing the requirements of the standard and evaluating the impact on our consolidated financial statements.

We are required to adopt the provisions of ASU 2016-13 effective January 1, 2020, but could elect to early adopt the provisions as of January 1, 2019. We expect to recognize the impacts of adopting ASU 2016-13 through a cumulative adjustment to retained earnings as of the date of adoption. As of the date of this report, we have not yet determined the date we will adopt ASU 2016-13.

Leases

On February 25, 2016, the FASB issued ASU 2016-02, “Leases” (“ASU 2016-02”). The core principle of ASU 2016-02 will require lessees to present right-of-use assets and lease liabilities on their balance sheets for operating leases, which under GAAP are currently not required to be reflected on their balance sheets.

ASU 2016-02 is effective for annual and interim periods beginning January 1, 2019. Early adoption of ASU 2016-02 is permitted. Upon adoption of ASU 2016-02, we are required to recognize and measure leases at the beginning of the earliest period presented in our consolidated financial statements using a modified retrospective approach. The modified retrospective approach includes a number of optional practical expedients that we may elect to apply.

On January 25, 2018, the FASB issued ASU 2018-01, “Leases: Land Easement Practical Expedient for Transition to ASU 2016-02. ASU 2018-01 permits reporting companies to elect to forego reassessments of land easements that exist or expire before the entity’s adoption of ASU 2016-02 and that were not previously accounted for as leases. We plan to adopt ASU 2018-01 at the same time we adopt ASU 2016-02.

We are in the process of implementing a new lease administration and accounting system. We plan to adopt ASU 2016-02 and ASU 2018-01 effective January 1, 2019. The adoption of ASU 2016-02 will result in our recognition of right of use assets and lease liabilities that we have not previously recorded. Although we believe it is premature as of the date of this report to provide any estimate of the impact of adopting ASU 2016-02, we do expect that it will have a material impact on our consolidated financial statements. Additionally, upon implementing ASU 2016-02, accounting for the failed-sale-leaseback transaction described in Note 3—Sale of Data Centers and Colocation Business will no longer be applicable based on our facts and circumstances, and the real estate assets and corresponding financing obligation described therein will be derecognized from our consolidated balance sheet.