Basis of presentation (Policies)	9 Months Ended
Basis of presentation (Policies)	Sep. 30, 2017
Accounting Policies [Abstract]
Use of Estimates	We have made a number of estimates and assumptions relating to the reporting of assets and liabilities and the disclosure of contingent assets and liabilities to prepare these condensed consolidated financial statements. Actual results could differ materially from these estimates. The most significant estimates are related to goodwill and other long-lived assets, pension and other retirement benefit obligations, legal contingencies and deferred tax assets.
Consolidation	Consolidation The condensed consolidated financial statements include our controlled subsidiaries. Control is determined based on ownership rights or, when applicable, based on whether we are considered to be the primary beneficiary of a variable interest entity. See "Venezuela" section below for further information. For controlled subsidiaries that are not wholly-owned, the noncontrolling interests are included in net income and in total equity. Investments in businesses that we do not control, but for which we have the ability to exercise significant influence over operating and financial policies, are accounted for under the equity method and our proportionate share of income or loss is recorded in other operating income (expense). Investments in businesses for which we do not have the ability to exercise significant influence over operating and financial policies are accounted for under the cost method or, if applicable, as available-for-sale securities. All intercompany accounts and transactions have been eliminated in consolidation.
Foreign Currency Translation	Foreign Currency Translation Our condensed consolidated financial statements are reported in U.S. dollars. Our foreign subsidiaries maintain their records primarily in the currency of the country in which they operate. The method of translating local currency financial information into U.S. dollars depends on whether the economy in which our foreign subsidiary operates has been designated as highly inflationary or not. Economies with an officially reported three-year cumulative inflation rate of more than 100% are considered highly inflationary. Assets and liabilities of foreign subsidiaries in non-highly inflationary economies are translated into U.S. dollars using rates of exchange at the balance sheet date. Translation adjustments are recorded in other comprehensive income (loss). Revenues and expenses are translated at rates of exchange in effect during the year. Transaction gains and losses are recorded in net income (loss). Foreign subsidiaries that operate in highly inflationary countries use the U.S. dollar as their functional currency. Local currency monetary assets and liabilities are remeasured into U.S. dollars using rates of exchange as of each balance sheet date, with remeasurement adjustments and other transaction gains and losses recognized in earnings. Non-monetary assets and liabilities do not fluctuate with changes in local currency exchange rates to the dollar. Revenues and expenses are translated at rates of exchange in effect during the year. Venezuela The economy in Venezuela has had significant inflation in the last several years. We consolidate our Venezuelan results using our accounting policy for subsidiaries operating in highly inflationary economies. We confirm that we control our Venezuela business for purposes of consolidation of financial statements. Specifically, while the Venezuela government has imposed restrictions that prevent the repatriation of funds, management continues to provide guidance and strategic oversight, including budgeting and forecasting. In addition, in this highly inflationary economy, the Venezuela business has negotiated price increases with certain customers to help offset cost inflation. We will continue to carefully monitor the situation in Venezuela and the impact that the economic and political environment in that country has on our ability to control our Venezuela operations.
New Accounting Standards	New Accounting Standards In May 2014, the FASB issued ASU 2014-09, Revenue From Contracts with Customers, a new standard related to revenue recognition, which requires an entity to recognize an amount of revenue to which it expects to be entitled for the transfer of promised goods and services to customers. The new standard will replace most of the existing revenue recognition standards in U.S. GAAP. In August 2015, the FASB issued ASU 2015-14, which defers the effective date of this new standard to January 1, 2018. Subsequently, the FASB has continued to refine the standard and has issued several amendments. The significant effects of the new standard for us will be associated with variable consideration and capitalization of costs to obtain contracts, such as sales commissions. Currently, we recognize the impact of pricing changes in the period they become fixed and determinable and we expense sales commissions and other costs to obtain contracts as they are incurred. We do not expect a material impact on our future consolidated statements of operations or consolidated balance sheets. However, the new guidance will result in expanded disclosures regarding our various performance obligations, revenue disaggregation and contractual rights. We intend to use the modified retrospective method to adopt the new standard. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows: Restricted Cash, which requires entities to include restricted cash and restricted cash equivalent balances with cash and cash equivalent balances in the statement of cash flows. ASU 2016-18 will impact the presentation of our statement of cash flows, will be effective January 1, 2018, and requires using a retrospective transition method to adopt the standard. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842), which will require the recognition of assets and liabilities by lessees for certain leases classified as operating leases under current accounting guidance and also requires expanded disclosures regarding leasing activities. ASU 2016-02 will be effective January 1, 2019 and we are required to use the modified retrospective method to adopt the new standard. We are assessing the potential impact of the standard on financial reporting. In March 2016, the FASB issued ASU 2016-09, Improvements to Employee Share-Based Payment Accounting, which simplifies how certain features related to share-based payments are accounted for and presented in the financial statements. We elected to early adopt this ASU in the fourth quarter of 2016 and, per the requirements of the pronouncement, we applied the amendments to the beginning of 2016. Under ASU 2016-09, accounting changes adopted using the modified retrospective method must be calculated as of the beginning of 2016 and reported as a cumulative-effect adjustment. As a result, we recognized a $0.2 million cumulative-effect adjustment to January 1, 2016 retained earnings for previously unrecognized excess tax benefits. We have elected to continue our previous accounting policy of estimating forfeitures and, therefore, we did not recognize any cumulative-effect adjustment related to forfeitures. ASU 2016-09 requires that accounting changes adopted using the prospective method should be reported in the applicable interim periods of 2016. We did not have any material changes to previously reported interim financial information in 2016 as it relates to the recognition of excess tax benefits in the statement of operations or the classification of excess tax benefits in the statement of cash flows. In the first nine months of 2017, the accounting under this ASU resulted in the recognition of $6.4 million in excess tax benefits. In March 2017, the FASB issued ASU 2017-07, Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost, which requires an entity to report the service cost component in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period. The other components of net benefit cost are required to be presented in the income statement separately from the service cost component and outside a subtotal of income from operations. We elected to early adopt this ASU in the first quarter of 2017 using the retrospective transition method for the periods presented. As a result, the condensed consolidated statements of operations have been updated to reflect this guidance. The adoption of this ASU resulted in a change in certain previously reported amounts in the first nine months of 2016 condensed consolidated statement of operations. Cost of revenues decreased $24.5 million, selling, general and administrative expenses decreased $5.0 million and operating profit as well as interest and other income (expense) increased $29.5 million compared to previously reported first nine months of 2016 amounts. The early adoption of this ASU had no impact on the previously reported income from continuing operations or net income for the prior year periods.