Background (Policies)	6 Months Ended
Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Consolidation policy	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.
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” and ASU 2016-16, “Intra-Entity Transfers of Assets Other Than Inventory”. Each of these is described further below. Revenue Recognition On May 28, 2014, the FASB issued ASU 2014-09 which replaces virtually all existing generally accepted accounting principles on revenue recognition and replaces them with a principles-based approach for determining revenue recognition using a new five step model. The core principle of ASU 2014-09 is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 also includes new accounting principles related to the deferral and amortization of contract acquisition and fulfillment costs. We adopted the new revenue recognition standard under the modified retrospective transition method. On January 1, 2018, we recorded a cumulative catch-up adjustment that increased our retained earnings by $128 million, net of $43 million of income taxes. Under ASU 2014-09, we are now deferring incremental contract acquisition and fulfillment costs and are recognizing such costs over either the initial contract (plus anticipated renewal contracts to which the costs relate) or the average customer life. Our deferred acquisition and fulfillment contract costs for our customers have average amortization periods of approximately 49 months for our business customers and 30 months for our consumer customers and are monitored every period to reflect any significant change in assumptions. We have material obligations to our customers in our indefeasible right of use arrangements, including certain long-term prepaid customer capacity arrangements. The majority of our indefeasible right of use arrangements are accounted for as operating leases. See Note 3—Revenue Recognition 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. The adoption of ASU 2016-16 did not have a material impact to our consolidated financial statements. Recently Issued 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"). 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. On July 30, 2018, the FASB issued ASU 2018-11, "Leases: Targeted Improvements". ("ASU 2018-11") provides entities with an additional (and optional) transition method to adopt the new leases standard. Under this new transition method, an entity initially applies the new leases standard at the adoption date and recognizes a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. We have not yet determined whether we will use the newly permitted adoption method. 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.

Recently Adopted Accounting Pronouncements

In the first quarter of 2018, we adopted Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers” and ASU 2016-16, “Intra-Entity Transfers of Assets Other Than Inventory”.

Each of these is described further below.

Revenue Recognition

On May 28, 2014, the FASB issued ASU 2014-09 which replaces virtually all existing generally accepted accounting principles on revenue recognition and replaces them with a principles-based approach for determining revenue recognition using a new five step model. The core principle of ASU 2014-09 is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 also includes new accounting principles related to the deferral and amortization of contract acquisition and fulfillment costs.

We adopted the new revenue recognition standard under the modified retrospective transition method. On January 1, 2018, we recorded a cumulative catch-up adjustment that increased our retained earnings by $128 million, net of $43 million of income taxes.

Under ASU 2014-09, we are now deferring incremental contract acquisition and fulfillment costs and are recognizing such costs over either the initial contract (plus anticipated renewal contracts to which the costs relate) or the average customer life. Our deferred acquisition and fulfillment contract costs for our customers have average amortization periods of approximately 49 months for our business customers and 30 months for our consumer customers and are monitored every period to reflect any significant change in assumptions.

We have material obligations to our customers in our indefeasible right of use arrangements, including certain long-term prepaid customer capacity arrangements. The majority of our indefeasible right of use arrangements are accounted for as operating leases.

See Note 3—Revenue Recognition 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. The adoption of ASU 2016-16 did not have a material impact to our consolidated financial statements.

Recently Issued 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"). 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.

On July 30, 2018, the FASB issued ASU 2018-11, "Leases: Targeted Improvements". ("ASU 2018-11") provides entities with an additional (and optional) transition method to adopt the new leases standard. Under this new transition method, an entity initially applies the new leases standard at the adoption date and recognizes a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. We have not yet determined whether we will use the newly permitted adoption method.

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.