Organization, Description of Business and Basis of Presentation	9 Months Ended
Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Description of Business and Basis of Presentation	Organization, Description of Business and Basis of Presentation United Rentals, Inc. (“Holdings,” “URI” or the “Company”) is principally a holding company and conducts its operations primarily through its wholly owned subsidiary, United Rentals (North America), Inc. (“URNA”), and subsidiaries of URNA. Holdings’ primary asset is its sole ownership of all issued and outstanding shares of common stock of URNA. URNA’s various credit agreements and debt instruments place restrictions on its ability to transfer funds to its shareholder. We rent equipment to a diverse customer base that includes construction and industrial companies, manufacturers, utilities, municipalities, homeowners and government entities in the United States, Canada and Europe. In addition to renting equipment, we sell new and used rental equipment, as well as related contractor supplies, parts and service. We have prepared the accompanying unaudited condensed consolidated financial statements in accordance with the accounting policies described in our annual report on Form 10-K for the year ended December 31, 2017 (the “2017 Form 10-K”) and the interim reporting requirements of Form 10-Q. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) have been condensed or omitted. These unaudited condensed consolidated financial statements should be read in conjunction with the 2017 Form 10-K. In our opinion, all adjustments, consisting only of normal recurring adjustments, which are necessary for a fair presentation of financial condition, operating results and cash flows for the interim periods presented have been made. Interim results of operations are not necessarily indicative of the results of the full year. New Accounting Pronouncements Leases. In March 2016, the Financial Accounting Standards Board (“FASB”) issued guidance ("Topic 842") to increase transparency and comparability among organizations by requiring (1) recognition of lease assets and lease liabilities on the balance sheet and (2) disclosure of key information about leasing arrangements. Some changes to the lessor accounting guidance were made to align both of the following: (1) the lessor accounting guidance with certain changes made to the lessee accounting guidance and (2) key aspects of the lessor accounting model with revenue recognition guidance. Topic 842 will be effective for fiscal years and interim periods beginning after December 15, 2018, and early adoption is permitted. A modified retrospective approach is required for adoption for all leases that exist at or commence after the date of initial application with an option to use certain practical expedients. We expect to use the package of practical expedients that allows us to not reassess: (1) whether any expired or existing contracts are or contain leases, (2) lease classification for any expired or existing leases and (3) initial direct costs for any expired or existing leases. We additionally expect to use the practical expedient that allows us to treat the lease and non-lease components of our leases as a single component for our real estate leases. We expect to adopt this guidance when effective, using the transition method that allows us to initially apply Topic 842 at the adoption date of January 1, 2019 and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. As discussed in note 2 to our condensed consolidated financial statements, most of our equipment rental revenues, which accounted for 86 percent of total revenues for the nine months ended September 30, 2018, will be accounted for under the current lease accounting standard ("Topic 840") until the adoption of Topic 842. We have tentatively concluded that no significant changes are expected to the accounting for most of our equipment rental revenues upon adoption of Topic 842. Under Topic 842, our operating leases, which include both real estate and non-rental equipment, will result in lease assets and lease liabilities being recognized on the balance sheet. We lease a significant portion of our branch locations, and also lease other premises used for purposes such as district and regional offices and service centers. We expect that the quantification of the amount of the lease assets and lease liabilities that we will recognize on our balance sheet will take a significant amount of time given the size of our lease portfolio. While our review of the lessee accounting requirements of Topic 842 is ongoing, we believe that the impact on our balance sheet, while not currently estimable, will be significant. Measurement of Credit Losses on Financial Instruments. In June 2016, the FASB issued guidance that will require companies to present assets held at amortized cost and available for sale debt securities net of the amount expected to be collected. The guidance requires the measurement of expected credit losses to be based on relevant information from past events, including historical experiences, current conditions and reasonable and supportable forecasts that affect collectibility. The guidance will be effective for fiscal years and interim periods beginning after December 15, 2019 and early adoption is permitted for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Different components of the guidance require modified retrospective or prospective adoption. We are currently assessing whether we will early adopt, and the impact on our financial statements is not currently estimable as it will depend on market conditions and our forecast expectations upon, and following, adoption. Simplifying the Test for Goodwill Impairment. In January 2017, the FASB issued guidance intended to simplify the subsequent accounting for goodwill acquired in a business combination. Prior guidance required utilizing a two-step process to review goodwill for impairment. A second step was required if there was an indication that an impairment may exist, and the second step required calculating the potential impairment by comparing the implied fair value of the reporting unit's goodwill (as if purchase accounting were performed on the testing date) with the carrying amount of the goodwill. The new guidance eliminates the second step from the goodwill impairment test. Under the new guidance, an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount, and then recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value (although the loss should not exceed the total amount of goodwill allocated to the reporting unit). The guidance requires prospective adoption and will be effective for annual or interim goodwill impairment tests in fiscal years beginning after December 15, 2019. Early adoption of this guidance is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. We are currently assessing whether we will early adopt. The guidance is not expected to have a significant impact on our financial statements. Derivatives and Hedging. In August 2017, the FASB issued guidance with the objective of improving the financial reporting of hedging relationships to better portray the economic results of an entity’s risk management activities in its financial statements. The guidance is additionally intended to simplify hedge accounting, and no longer requires separate measurement and reporting of hedge ineffectiveness. For cash flow and net investment hedges existing at the date of adoption, entities must apply a cumulative-effect adjustment related to eliminating the separate measurement of ineffectiveness to accumulated other comprehensive income with a corresponding adjustment to the opening balance of retained earnings. The amended presentation and disclosure guidance is required prospectively. The guidance will be effective for fiscal years and interim periods beginning after December 15, 2018, and early adoption is permitted. We are currently assessing whether we will early adopt. Given our currently limited use of derivative instruments, the guidance is not expected to have a significant impact on our financial statements. Guidance Adopted in 2018 Revenue from Contracts with Customers. See note 2 to our condensed consolidated financial statements for a discussion of our revenue recognition accounting following our adoption in the first quarter of 2018 of FASB guidance addressing the principles for recognizing revenue. Statement of Cash Flows. In 2018, we retrospectively adopted guidance that was issued to reduce the diversity in the presentation of certain cash receipts and cash payments presented and classified in the statement of cash flows. The guidance addresses the following specific cash flow issues: (1) debt prepayment or debt extinguishment costs, (2) settlement of zero-coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing, (3) contingent consideration payments made after a business combination, (4) proceeds from the settlement of insurance claims, (5) proceeds from settlement of corporate-owned life insurance policies, including bank-owned life insurance policies, (6) distributions received from equity method investees, (7) beneficial interests in securitization transitions and (8) separately identifiable cash flows and application of predominance principle. The adoption of this guidance did not have a significant impact on our financial statements for the three and nine months ended September 30, 2018 or 2017. Intra-Entity Transfers of Assets Other Than Inventory. In 2018, we adopted guidance that requires companies to recognize the income tax effects of intra-entity sales and transfers of assets other than inventory in the period in which the transfer occurs. The adoption of this guidance did not have a significant impact on our financial statements. Clarifying the Definition of a Business. In 2018, we adopted guidance that was issued to clarify the definition of a business with the objective of assisting entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The definition of a business affects many areas of accounting including acquisitions, disposals, goodwill, and consolidation. The guidance is intended to make determining when a set of assets and activities is a business more consistent and cost-efficient. The future impact of this guidance will depend on the nature of our future activities, and fewer transactions may be treated as acquisitions (or disposals) of businesses after adoption. Stock Compensation: Scope of Modification Accounting. In 2018, we prospectively adopted guidance that was issued to provide clarity and reduce both the (1) diversity in practice and (2) cost and complexity when changing the terms or conditions of share-based payment awards. Under the updated guidance, a modification is defined as a change in the terms or conditions of a share-based payment award, and an entity should account for the effects of a modification unless all of the following are met: 1.The fair value of the modified award is the same as the fair value of the original award immediately before the original award is modified. If the modification does not affect any of the inputs to the valuation techniques that the entity uses to value the award, the entity is not required to estimate the value immediately before and after the modification. 2.The vesting conditions of the modified award are the same as the vesting conditions of the original award immediately before the original award is modified. 3.The classification of the modified award as an equity instrument or a liability instrument is the same as the classification of the original award immediately before the original award is modified. The majority of our modifications relate to the acceleration of vesting conditions. The accounting for such modifications did not change under the adopted guidance, which did not have a significant impact on our financial statements. Tax Cuts and Jobs Act The Tax Cuts and Jobs Act (the "Tax Act") was enacted in December 2017. The Act reduced the U.S. federal corporate tax rate from 35 percent to 21 percent, requires companies to pay a one-time transition tax on earnings of certain foreign subsidiaries that were previously tax deferred and creates new taxes on certain foreign sourced earnings. As of December 31, 2017, we were able to determine a reasonable estimate of (1) the effects on our existing deferred tax balances and (2) the one-time transition tax. We recognized a provisional income tax benefit of $689 in the year ended December 31, 2017 associated with these items that we reasonably estimated. As of September 30, 2018, we have not changed the provisional estimate recognized in 2017 associated with the effects on our existing deferred tax balances. During the three and nine months ended September 30, 2018, we increased the estimated one-time transition tax by $6. The Tax Act subjects U.S. shareholders to a tax on global intangible low-taxed income (“GILTI”) earned by certain foreign subsidiaries. Entities can make an accounting policy election to either recognize deferred taxes for temporary basis differences expected to reverse as GILTI in future years or provide for the tax expense related to GILTI in the year the tax is incurred. Given the complexity of the GILTI provisions, we are still evaluating the tax impact and have not yet made the accounting policy election. As of September 30, 2018, we were able to reasonably estimate provisional adjustments, based on current year operations only, related to GILTI and recognized the immaterial adjustments in our financial statements. In all cases as it relates to the Tax Act, we will continue to refine our calculations as additional analysis is completed and as we gain a more thorough understanding of the tax law. All amounts recognized associated with the Tax Act as of September 30, 2018 are provisional. Given the complexity of the Tax Act, we are still evaluating the tax impact. We expect to complete the accounting in the fourth quarter of 2018. As noted above, most of the impact of the Act was recognized in 2017, with $6 of additional expense recognized during the three and nine months ended September 30, 2018.

Organization, Description of Business and Basis of Presentation

United Rentals, Inc. (“Holdings,” “URI” or the “Company”) is principally a holding company and conducts its operations primarily through its wholly owned subsidiary, United Rentals (North America), Inc. (“URNA”), and subsidiaries of URNA. Holdings’ primary asset is its sole ownership of all issued and outstanding shares of common stock of URNA. URNA’s various credit agreements and debt instruments place restrictions on its ability to transfer funds to its shareholder.

We rent equipment to a diverse customer base that includes construction and industrial companies, manufacturers, utilities, municipalities, homeowners and government entities in the United States, Canada and Europe. In addition to renting equipment, we sell new and used rental equipment, as well as related contractor supplies, parts and service.

We have prepared the accompanying unaudited condensed consolidated financial statements in accordance with the accounting policies described in our annual report on Form 10-K for the year ended December 31, 2017 (the “2017 Form 10-K”) and the interim reporting requirements of Form 10-Q. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) have been condensed or omitted. These unaudited condensed consolidated financial statements should be read in conjunction with the 2017 Form 10-K.

In our opinion, all adjustments, consisting only of normal recurring adjustments, which are necessary for a fair presentation of financial condition, operating results and cash flows for the interim periods presented have been made. Interim results of operations are not necessarily indicative of the results of the full year.

New Accounting Pronouncements

Leases. In March 2016, the Financial Accounting Standards Board (“FASB”) issued guidance ("Topic 842") to increase transparency and comparability among organizations by requiring (1) recognition of lease assets and lease liabilities on the balance sheet and (2) disclosure of key information about leasing arrangements. Some changes to the lessor accounting guidance were made to align both of the following: (1) the lessor accounting guidance with certain changes made to the lessee accounting guidance and (2) key aspects of the lessor accounting model with revenue recognition guidance. Topic 842 will be effective for fiscal years and interim periods beginning after December 15, 2018, and early adoption is permitted. A modified retrospective approach is required for adoption for all leases that exist at or commence after the date of initial application with an option to use certain practical expedients. We expect to use the package of practical expedients that allows us to not reassess: (1) whether any expired or existing contracts are or contain leases, (2) lease classification for any expired or existing leases and (3) initial direct costs for any expired or existing leases. We additionally expect to use the practical expedient that allows us to treat the lease and non-lease components of our leases as a single component for our real estate leases. We expect to adopt this guidance when effective, using the transition method that allows us to initially apply Topic 842 at the adoption date of January 1, 2019 and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption.

As discussed in note 2 to our condensed consolidated financial statements, most of our equipment rental revenues, which accounted for 86 percent of total revenues for the nine months ended September 30, 2018, will be accounted for under the current lease accounting standard ("Topic 840") until the adoption of Topic 842. We have tentatively concluded that no significant changes are expected to the accounting for most of our equipment rental revenues upon adoption of Topic 842.

Under Topic 842, our operating leases, which include both real estate and non-rental equipment, will result in lease assets and lease liabilities being recognized on the balance sheet. We lease a significant portion of our branch locations, and also lease other premises used for purposes such as district and regional offices and service centers. We expect that the quantification of the amount of the lease assets and lease liabilities that we will recognize on our balance sheet will take a significant amount of time given the size of our lease portfolio. While our review of the lessee accounting requirements of Topic 842 is ongoing, we believe that the impact on our balance sheet, while not currently estimable, will be significant.

Measurement of Credit Losses on Financial Instruments. In June 2016, the FASB issued guidance that will require companies to present assets held at amortized cost and available for sale debt securities net of the amount expected to be collected. The guidance requires the measurement of expected credit losses to be based on relevant information from past events, including historical experiences, current conditions and reasonable and supportable forecasts that affect collectibility. The guidance will be effective for fiscal years and interim periods beginning after December 15, 2019 and early adoption is permitted for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Different components of the guidance require modified retrospective or prospective adoption. We are currently assessing whether we will early adopt, and the impact on our financial statements is not currently estimable as it will depend on market conditions and our forecast expectations upon, and following, adoption.

Simplifying the Test for Goodwill Impairment. In January 2017, the FASB issued guidance intended to simplify the subsequent accounting for goodwill acquired in a business combination. Prior guidance required utilizing a two-step process to review goodwill for impairment. A second step was required if there was an indication that an impairment may exist, and the second step required calculating the potential impairment by comparing the implied fair value of the reporting unit's goodwill (as if purchase accounting were performed on the testing date) with the carrying amount of the goodwill. The new guidance eliminates the second step from the goodwill impairment test. Under the new guidance, an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount, and then recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value (although the loss should not exceed the total amount of goodwill allocated to the reporting unit). The guidance requires prospective adoption and will be effective for annual or interim goodwill impairment tests in fiscal years beginning after December 15, 2019. Early adoption of this guidance is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. We are currently assessing whether we will early adopt. The guidance is not expected to have a significant impact on our financial statements.

Derivatives and Hedging. In August 2017, the FASB issued guidance with the objective of improving the financial reporting of hedging relationships to better portray the economic results of an entity’s risk management activities in its financial statements. The guidance is additionally intended to simplify hedge accounting, and no longer requires separate measurement and reporting of hedge ineffectiveness. For cash flow and net investment hedges existing at the date of adoption, entities must apply a cumulative-effect adjustment related to eliminating the separate measurement of ineffectiveness to accumulated other comprehensive income with a corresponding adjustment to the opening balance of retained earnings. The amended presentation and disclosure guidance is required prospectively. The guidance will be effective for fiscal years and interim periods beginning after December 15, 2018, and early adoption is permitted. We are currently assessing whether we will early adopt. Given our currently limited use of derivative instruments, the guidance is not expected to have a significant impact on our financial statements.

Guidance Adopted in 2018

Revenue from Contracts with Customers. See note 2 to our condensed consolidated financial statements for a discussion of our revenue recognition accounting following our adoption in the first quarter of 2018 of FASB guidance addressing the principles for recognizing revenue.

Statement of Cash Flows. In 2018, we retrospectively adopted guidance that was issued to reduce the diversity in the presentation of certain cash receipts and cash payments presented and classified in the statement of cash flows. The guidance addresses the following specific cash flow issues: (1) debt prepayment or debt extinguishment costs, (2) settlement of zero-coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing, (3) contingent consideration payments made after a business combination, (4) proceeds from the settlement of insurance claims, (5) proceeds from settlement of corporate-owned life insurance policies, including bank-owned life insurance policies, (6) distributions received from equity method investees, (7) beneficial interests in securitization transitions and (8) separately identifiable cash flows and application of predominance principle. The adoption of this guidance did not have a significant impact on our financial statements for the three and nine months ended September 30, 2018 or 2017.

Intra-Entity Transfers of Assets Other Than Inventory. In 2018, we adopted guidance that requires companies to recognize the income tax effects of intra-entity sales and transfers of assets other than inventory in the period in which the transfer occurs. The adoption of this guidance did not have a significant impact on our financial statements.

Clarifying the Definition of a Business. In 2018, we adopted guidance that was issued to clarify the definition of a business with the objective of assisting entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The definition of a business affects many areas of accounting including acquisitions, disposals, goodwill, and consolidation. The guidance is intended to make determining when a set of assets and activities is a business more consistent and cost-efficient. The future impact of this guidance will depend on the nature of our future activities, and fewer transactions may be treated as acquisitions (or disposals) of businesses after adoption.

Stock Compensation: Scope of Modification Accounting. In 2018, we prospectively adopted guidance that was issued to provide clarity and reduce both the (1) diversity in practice and (2) cost and complexity when changing the terms or conditions of share-based payment awards. Under the updated guidance, a modification is defined as a change in the terms or conditions of a share-based payment award, and an entity should account for the effects of a modification unless all of the following are met:

1.The fair value of the modified award is the same as the fair value of the original award immediately before the original award is modified. If the modification does not affect any of the inputs to the valuation techniques that the entity uses to value the award, the entity is not required to estimate the value immediately before and after the modification.

2.The vesting conditions of the modified award are the same as the vesting conditions of the original award immediately before the original award is modified.

3.The classification of the modified award as an equity instrument or a liability instrument is the same as the classification of the original award immediately before the original award is modified.

The majority of our modifications relate to the acceleration of vesting conditions. The accounting for such modifications did not change under the adopted guidance, which did not have a significant impact on our financial statements.

Tax Cuts and Jobs Act

The Tax Cuts and Jobs Act (the "Tax Act") was enacted in December 2017. The Act reduced the U.S. federal corporate tax rate from 35 percent to 21 percent, requires companies to pay a one-time transition tax on earnings of certain foreign subsidiaries that were previously tax deferred and creates new taxes on certain foreign sourced earnings. As of December 31, 2017, we were able to determine a reasonable estimate of (1) the effects on our existing deferred tax balances and (2) the one-time transition tax. We recognized a provisional income tax benefit of $689 in the year ended December 31, 2017 associated with these items that we reasonably estimated. As of September 30, 2018, we have not changed the provisional estimate recognized in 2017 associated with the effects on our existing deferred tax balances. During the three and nine months ended September 30, 2018, we increased the estimated one-time transition tax by $6. The Tax Act subjects U.S. shareholders to a tax on global intangible low-taxed income (“GILTI”) earned by certain foreign subsidiaries. Entities can make an accounting policy election to either recognize deferred taxes for temporary basis differences expected to reverse as GILTI in future years or provide for the tax expense related to GILTI in the year the tax is incurred. Given the complexity of the GILTI provisions, we are still evaluating the tax impact and have not yet made the accounting policy election. As of September 30, 2018, we were able to reasonably estimate provisional adjustments, based on current year operations only, related to GILTI and recognized the immaterial adjustments in our financial statements. In all cases as it relates to the Tax Act, we will continue to refine our calculations as additional analysis is completed and as we gain a more thorough understanding of the tax law.

All amounts recognized associated with the Tax Act as of September 30, 2018 are provisional. Given the complexity of the Tax Act, we are still evaluating the tax impact. We expect to complete the accounting in the fourth quarter of 2018. As noted above, most of the impact of the Act was recognized in 2017, with $6 of additional expense recognized during the three and nine months ended September 30, 2018.