Major Accounting Policies	12 Months Ended
Sep. 30, 2016
Accounting Policies [Abstract]
Major Accounting Policies	Estimates and Assumptions The preparation of the Annual Combined Financial Statements in conformity with GAAP requires management to make estimates and assumptions that affect amounts reported in the Annual Combined Financial Statements and accompanying notes, including allocations of costs during the reporting period. Management’s estimates are based on historical experience, facts and circumstances available at the time, and various other assumptions that are believed to be reasonable. Actual results could differ from those estimates. Revenue Recognition Revenue from product sales is recognized as risk and title to the product transfer to the customer (which generally occurs at the time shipment is made), the sales price is fixed or determinable, and collectability is reasonably assured. Sales returns and allowances are generally not a business practice in the industry. We use both the completed contract and percentage-of-completion methods to record revenue from equipment sale contracts. The completed contract method is used in circumstances in which financial position and results of operations are not materially different from those resulting from use of the percentage-of-completion method, e.g., certain short-term contracts. We use the percentage-of-completion method when we can make reasonably dependable estimates of progress toward completion and performance is expected. Under the percentage-of-completion method, revenue from the sale of major equipment is recognized primarily based on labor hours incurred to date compared with total estimated labor hours. Under the completed contract method, revenue and cost is recognized when the equipment is completed and transferred to the customer. Changes to estimated labor hours under the percentage-of-completion method or anticipated losses under either method, if any, are recognized in the period determined. Revenue from on-site services are generally fixed monthly fee arrangements for which we recognize revenue as the services are performed. Amounts billed for shipping and handling fees are classified as sales in the combined income statements. Amounts billed for sales and use taxes, value-added taxes, and certain excise and other specific transactional taxes imposed on revenue-producing transactions are presented on a net basis and excluded from sales in the combined income statements. We record a liability until remitted to the respective taxing authority. Cost of Sales Cost of sales predominantly represents the cost of tangible products sold. These costs include labor, raw materials, depreciation, production supplies, and materials packaging costs. Costs incurred for shipping and handling are also included in cost of sales. Depreciation Depreciation is recorded using the straight-line method, which deducts equal amounts of the cost of each asset from earnings every year over its expected economic useful life. The principal lives for major classes of plant and equipment are summarized in Note 8, Plant and Equipment, Net. Selling and Administrative The principal components of selling and administrative expenses are compensation, advertising, and promotional costs. Research and Development Research and development costs are expensed as incurred. Research and development expenses include employee costs, materials, contract services, research agreements, and other external spending related to the discovery and development of new products, enhancement of existing products and regulatory approval of new and existing products. Postemployment Benefits We provide termination benefits to employees as part of ongoing benefit arrangements and record a liability for termination benefits when probable and estimable. These criteria are met when management, with the appropriate level of authority, approves and commits to its plan of action for termination; the plan identifies the employees to be terminated and their related benefits; and the plan is to be completed within one year. We typically do not provide one-time benefit arrangements of significance. Fair Value Measurements We are required to measure certain assets and liabilities at fair value, either upon initial measurement or for subsequent accounting or reporting. For example, fair value is used in the initial measurement of net assets acquired in a business combination; on a recurring basis in the measurement of derivative financial instruments; and on a nonrecurring basis when long-lived assets are written down to fair value when held for sale or determined to be impaired. Refer to Note 13, “Fair Value”, for information on the methods and assumptions used in our fair value measurements. Financial Instruments We address certain financial exposures through a controlled program of risk management that includes the use of derivative financial instruments. The hedging relationship between the underlying financial exposures and the related hedging instrument is documented on the date the derivative is entered into with the counterparty. We periodically use forward exchange contracts to hedge a highly anticipated foreign currency transaction such as the purchase of plant and equipment. Derivatives such as these that specifically hedge exposures for Versum are included in the Annual Combined Financial Statements. The fair values of these hedging instruments were not material for the periods presented. We also enter into derivative contracts to hedge exposures at the corporate level, such as interest rate swaps to manage the interest rate mix of third party debt or forward exchange contracts to hedge intercompany loans denominated in a foreign currency. Because these activities represent activities that are managed at Air Products and are not specific to any of the Versum businesses, the impacts of these transactions were not included in the Annual Combined Financial Statements. Foreign Currency Since we do business in many foreign countries, fluctuations in currency exchange rates affect our financial position and results of operations. In certain of our foreign operations, the local currency is considered the functional currency. These foreign subsidiaries translate their assets and liabilities into U.S. dollars at current exchange rates in effect at the end of the fiscal period. The gains or losses that result from this process are shown as translation adjustments in accumulated other comprehensive income (loss) in the Air Products’ invested equity section of the annual combined balance sheet. The revenue and expense accounts of these foreign subsidiaries are translated into U.S. dollars at the average exchange rates that prevail during the period. Therefore, the U.S. dollar value of these items on the income statement fluctuates from period to period, depending on the value of the dollar against foreign currencies. Some transactions are made in currencies different from an entity’s functional currency. Gains and losses from these foreign currency transactions are generally included in other income (expense), net on our combined income statements as they occur. Litigation Accruals for litigation are made when the information available indicates that it is probable that a liability has been incurred and the amount can be reasonably estimated. When only a range of possible loss can be established, the most probable amount in the range is accrued. If no amount within this range is a better estimate than any other amount within the range, the minimum amount in the range is accrued. The accrual for a litigation loss contingency includes estimates of potential damages and other directly related costs expected to be incurred. Litigation liabilities and expenditures included in the Annual Combined Financial Statements were not material for the periods presented. Share-Based Compensation Our employees participated in Air Products’ share-based compensation plans, which include stock options, deferred stock units, and restricted stock. The Annual Combined Financial Statements include share-based compensation expense associated with our employees and Air Products’ costs that have been allocated to us based on awards and terms previously granted. The grant-date fair value of these awards is expensed over the vesting period during which employees perform related services. Expense recognition is accelerated for retirement-eligible individuals who would meet the requirements for vesting of awards upon their retirement. The Black Scholes model was utilized to value stock option awards. The grant date fair value of the deferred stock units tied to a market condition is estimated using a Monte Carlo simulation model. For the years ended September 30, 2016, 2015, and 2014, share-based compensation expense of $5.0 million, $4.7 million, and $4.6 million, respectively, was included in the Annual Combined Financial Statements. Income Taxes Certain of our operations included in our Annual Combined Financial Statements are divisions of legal entities included in Air Products consolidated U.S. federal and state income tax returns, or tax returns of non-U.S. subsidiaries of Air Products. The provision for income taxes and related annual combined balance sheet accounts of such entities have been prepared and presented in the Annual Combined Financial Statements based on a stand-alone basis separate from Air Products. Differences between our separate return income tax provision and cash flows attributable to income taxes for operations that were divisions of legal entities have been recognized as capital contributions from, or dividends to, Air Products, within Air Products’ net investment. As a stand-alone entity, our deferred taxes and effective tax rate may differ from those in historical periods. We account for income taxes under the liability method. Under this method, deferred tax assets and liabilities are recognized for the tax effects of temporary differences between the financial reporting and tax bases of assets and liabilities measured using enacted tax rates. The cumulative impact of a change in tax rates or regulations is included in income tax expense in the period that includes the enactment date. A tax benefit for an uncertain tax position is recognized when it is more likely than not that the position will be sustained upon examination based on its technical merits. This position is measured as the largest amount of tax benefit that is greater than 50% likely of being realized. Interest and penalties related to unrecognized tax benefits are recognized as a component of income tax expense. The majority of the accrued U.S. federal, state, and foreign income tax balances are treated as settled with Air Products as of the end of each year. Therefore, they are included in Air Products’ net investment in the Annual Combined Financial Statements. Non-controlling Interests We consolidate investments that we control but do not wholly own. The Annual Combined Financial Statements include all assets, liabilities, revenues, and expenses of our joint venture in Taiwan for which we have a 74% ownership interest during the periods presented in the Annual Combined Financial Statements. The ownership interests held by third party non-controlling partners are presented as non-controlling interests in our annual combined balance sheets. Any net income or loss attributed to the non-controlling partners is presented as such in the combined income statements. The activity for non-controlling interests for the years ended September 30, 2016, 2015 and 2014 is presented in the annual combined statements of changes in Air Products’ invested equity and non-controlling interests. Cash and Cash Items Cash and cash items generally include cash, time deposits, and certificates of deposit acquired with an original maturity of three months or less for our foreign entities. Cash is managed centrally and most cash generated by our business was remitted to Air Products. Such centralized cash management transactions relating to our business are reflected through Air Products’ net investment. Accordingly, none of the centrally managed cash at the Air Products’ corporate level has been reflected in our Annual Combined Financial Statements. Restricted Cash Restricted cash consists of cash restricted for payment to Air Products subsequent to the Separation. Trade Receivables, net Trade receivables comprise amounts owed to us through our operating activities and are presented net of allowances for doubtful accounts. The allowances for doubtful accounts represent estimated uncollectible receivables associated with potential customer defaults on contractual obligations. A provision for customer defaults is made on a general formula basis when it is determined that the risk of some default is probable and estimable but cannot yet be associated with specific customers. The assessment of the likelihood of customer defaults is based on various factors, including the length of time the receivables are past due, historical experience, and existing economic conditions. The allowance also includes amounts for certain customers where a risk of default has been specifically identified, considering factors such as the financial condition of the customer and customer disputes over contractual terms and conditions. Allowance for doubtful accounts were $0.8 million and $0.8 million as of fiscal year end September 30, 2016 and 2015, respectively. Provisions to the allowance for doubtful accounts charged against income were not material in fiscal 2016, 2015, and 2014. Inventories Inventories are stated at the lower of cost or market. We write down our inventories for estimated obsolescence or unmarketable inventory based upon assumptions about future demand and market conditions. We utilize the last-in, first-out (“LIFO”) method for determining the cost of inventories in the United States. Inventories outside of the United States are accounted for on the first-in, first-out (“FIFO”) method, as the LIFO method is not generally permitted in the foreign jurisdictions we operate. Equity Investments The equity method of accounting is used when we exercise significant influence but do not have operating control, generally assumed to be 20% to 50% ownership. Under the equity method, original investments are recorded at cost and adjusted by our share of undistributed earnings or losses of these companies. Equity investments are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the investment may not be recoverable. The Annual Combined Financial Statements include our investment in and proportionate share of the income from our 20% owned equity affiliate, Daido Air Products Electronics, Inc. During the first quarter of 2016, we sold our investment in this affiliate. Refer to Note 6, “Sale of Equity Affiliate”, for additional information. Plant and Equipment Plant and equipment is stated at cost less accumulated depreciation. Construction costs, labor, and applicable overhead related to installations are capitalized. Expenditures for additions and improvements that extend the lives or increase the capacity of plant assets are capitalized. The costs of maintenance and repairs of plant and equipment are charged to expense as incurred. Fully depreciated assets are retained in the gross plant and equipment and accumulated depreciation accounts until they are removed from service. In the case of disposals, assets and related depreciation are removed from the accounts, and the net amounts, less proceeds from disposal, are included in income. Impairment of Long-Lived Assets Long-lived assets are grouped for impairment testing at the lowest level for which there are identifiable cash flows that are largely independent of the cash flows of other assets and liabilities and are evaluated for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset group may not be recoverable. We assess recoverability by comparing the carrying amount of the asset group to estimated undiscounted future cash flows expected to be generated by the asset group. If an asset group is considered impaired, the impairment loss to be recognized is measured as the amount by which the asset group’s carrying amount exceeds its fair value. Long-lived assets to be sold are reported at the lower of carrying amount or fair value less cost to sell. Goodwill Business combinations are accounted for using the acquisition method. The purchase price is allocated to the assets acquired and liabilities assumed based on their estimated fair market values. Any excess purchase price over the fair market value of the net assets acquired, including identified intangibles, is recorded as goodwill. Preliminary purchase price allocations are made at the date of acquisition and finalized when information needed to affirm underlying estimates is obtained, within a maximum allocation period of one year. Goodwill is subject to impairment testing at least annually. In addition, goodwill is tested more frequently if a change in circumstances or the occurrence of events indicates that potential impairment exists. Intangible Assets Intangible assets with determinable lives primarily consist of customer relationships and purchased patents and technology. The cost of intangible assets with determinable lives is amortized on a straight-line basis over the estimated period of economic benefit. Amortizable lives are adjusted whenever there is a change in the estimated period of economic benefit. No residual value is estimated for intangible assets. Retirement Benefits Air Products sponsors defined benefit pension plans, defined contribution plans, and other post-employment benefit plans that are shared amongst its businesses. Participation of our employees in these plans is reflected in the Annual Combined Financial Statements as though Versum participates in a multiemployer plan with Air Products. A proportionate share of cost is reflected in these Annual Combined Financial Statements, primarily within selling and administrative expenses. Assets and liabilities of such plans are retained by Air Products. Air Products’ Net Investment Air Products’ net investment in our business is presented as “Air Products’ net investment” in lieu of stockholders’ equity, as a stand-alone legal and capital structure did not exist for the historical periods presented. Earnings Per Share Versum earnings per share for 2016, 2015 and 2014 were calculated using the shares that were distributed to Air Products stockholders immediately following the Separation. For periods prior to the Separation it is assumed that there are no dilutive equity instruments as there were no equity awards in Versum outstanding prior to the Separation.

Estimates and Assumptions

The preparation of the Annual Combined Financial Statements in conformity with GAAP requires management to make estimates and assumptions that affect amounts reported in the Annual Combined Financial Statements and accompanying notes, including allocations of costs during the reporting period. Management’s estimates are based on historical experience, facts and circumstances available at the time, and various other assumptions that are believed to be reasonable. Actual results could differ from those estimates.

Revenue Recognition

Revenue from product sales is recognized as risk and title to the product transfer to the customer (which generally occurs at the time shipment is made), the sales price is fixed or determinable, and collectability is reasonably assured. Sales returns and allowances are generally not a business practice in the industry.

We use both the completed contract and percentage-of-completion methods to record revenue from equipment sale contracts. The completed contract method is used in circumstances in which financial position and results of operations are not materially different from those resulting from use of the percentage-of-completion method, e.g., certain short-term contracts. We use the percentage-of-completion method when we can make reasonably dependable estimates of progress toward completion and performance is expected.

Under the percentage-of-completion method, revenue from the sale of major equipment is recognized primarily based on labor hours incurred to date compared with total estimated labor hours. Under the completed contract method, revenue and cost is recognized when the equipment is completed and transferred to the customer. Changes to estimated labor hours under the percentage-of-completion method or anticipated losses under either method, if any, are recognized in the period determined.

Revenue from on-site services are generally fixed monthly fee arrangements for which we recognize revenue as the services are performed.

Amounts billed for shipping and handling fees are classified as sales in the combined income statements.

Amounts billed for sales and use taxes, value-added taxes, and certain excise and other specific transactional taxes imposed on revenue-producing transactions are presented on a net basis and excluded from sales in the combined income statements. We record a liability until remitted to the respective taxing authority.

Cost of Sales

Cost of sales predominantly represents the cost of tangible products sold. These costs include labor, raw materials, depreciation, production supplies, and materials packaging costs. Costs incurred for shipping and handling are also included in cost of sales.

Depreciation

Depreciation is recorded using the straight-line method, which deducts equal amounts of the cost of each asset from earnings every year over its expected economic useful life. The principal lives for major classes of plant and equipment are summarized in Note 8, Plant and Equipment, Net.

Selling and Administrative

The principal components of selling and administrative expenses are compensation, advertising, and promotional costs.

Research and Development

Research and development costs are expensed as incurred. Research and development expenses include employee costs, materials, contract services, research agreements, and other external spending related to the discovery and development of new products, enhancement of existing products and regulatory approval of new and existing products.

Postemployment Benefits

We provide termination benefits to employees as part of ongoing benefit arrangements and record a liability for termination benefits when probable and estimable. These criteria are met when management, with the appropriate level of authority, approves and commits to its plan of action for termination; the plan identifies the employees to be terminated and their related benefits; and the plan is to be completed within one year. We typically do not provide one-time benefit arrangements of significance.

Fair Value Measurements

We are required to measure certain assets and liabilities at fair value, either upon initial measurement or for subsequent accounting or reporting. For example, fair value is used in the initial measurement of net assets acquired in a business combination; on a recurring basis in the measurement of derivative financial instruments; and on a nonrecurring basis when long-lived assets are written down to fair value when held for sale or determined to be impaired. Refer to Note 13, “Fair Value”, for information on the methods and assumptions used in our fair value measurements.

Financial Instruments

We address certain financial exposures through a controlled program of risk management that includes the use of derivative financial instruments. The hedging relationship between the underlying financial exposures and the related hedging instrument is documented on the date the derivative is entered into with the counterparty. We periodically use forward exchange contracts to hedge a highly anticipated foreign currency transaction such as the purchase of plant and equipment. Derivatives such as these that specifically hedge exposures for Versum are included in the Annual Combined Financial Statements. The fair values of these hedging instruments were not material for the periods presented.

We also enter into derivative contracts to hedge exposures at the corporate level, such as interest rate swaps to manage the interest rate mix of third party debt or forward exchange contracts to hedge intercompany loans denominated in a foreign currency. Because these activities represent activities that are managed at Air Products and are not specific to any of the Versum businesses, the impacts of these transactions were not included in the Annual Combined Financial Statements.

Foreign Currency

Since we do business in many foreign countries, fluctuations in currency exchange rates affect our financial position and results of operations.

In certain of our foreign operations, the local currency is considered the functional currency. These foreign subsidiaries translate their assets and liabilities into U.S. dollars at current exchange rates in effect at the end of the fiscal period. The gains or losses that result from this process are shown as translation adjustments in accumulated other comprehensive income (loss) in the Air Products’ invested equity section of the annual combined balance sheet. The revenue and expense accounts of these foreign subsidiaries are translated into U.S. dollars at the average exchange rates that prevail during the period. Therefore, the U.S. dollar value of these items on the income statement fluctuates from period to period, depending on the value of the dollar against foreign currencies. Some transactions are made in currencies different from an entity’s functional currency. Gains and losses from these foreign currency transactions are generally included in other income (expense), net on our combined income statements as they occur.

Litigation

Accruals for litigation are made when the information available indicates that it is probable that a liability has been incurred and the amount can be reasonably estimated. When only a range of possible loss can be established, the most probable amount in the range is accrued. If no amount within this range is a better estimate than any other amount within the range, the minimum amount in the range is accrued. The accrual for a litigation loss contingency includes estimates of potential damages and other directly related costs expected to be incurred. Litigation liabilities and expenditures included in the Annual Combined Financial Statements were not material for the periods presented.

Share-Based Compensation

Our employees participated in Air Products’ share-based compensation plans, which include stock options, deferred stock units, and restricted stock. The Annual Combined Financial Statements include share-based compensation expense associated with our employees and Air Products’ costs that have been allocated to us based on awards and terms previously granted. The grant-date fair value of these awards is expensed over the vesting period during which employees perform related services. Expense recognition is accelerated for retirement-eligible individuals who would meet the requirements for vesting of awards upon their retirement. The Black Scholes model was utilized to value stock option awards. The grant date fair value of the deferred stock units tied to a market condition is estimated using a Monte Carlo simulation model. For the years ended September 30, 2016, 2015, and 2014, share-based compensation expense of $5.0 million, $4.7 million, and $4.6 million, respectively, was included in the Annual Combined Financial Statements.

Income Taxes

Certain of our operations included in our Annual Combined Financial Statements are divisions of legal entities included in Air Products consolidated U.S. federal and state income tax returns, or tax returns of non-U.S. subsidiaries of Air Products. The provision for income taxes and related annual combined balance sheet accounts of such entities have been prepared and presented in the Annual Combined Financial Statements based on a stand-alone basis separate from Air Products. Differences between our separate return income tax provision and cash flows attributable to income taxes for operations that were divisions of legal entities have been recognized as capital contributions from, or dividends to, Air Products, within Air Products’ net investment. As a stand-alone entity, our deferred taxes and effective tax rate may differ from those in historical periods.

We account for income taxes under the liability method. Under this method, deferred tax assets and liabilities are recognized for the tax effects of temporary differences between the financial reporting and tax bases of assets and liabilities measured using enacted tax rates. The cumulative impact of a change in tax rates or regulations is included in income tax expense in the period that includes the enactment date.

A tax benefit for an uncertain tax position is recognized when it is more likely than not that the position will be sustained upon examination based on its technical merits. This position is measured as the largest amount of tax benefit that is greater than 50% likely of being realized. Interest and penalties related to unrecognized tax benefits are recognized as a component of income tax expense.

The majority of the accrued U.S. federal, state, and foreign income tax balances are treated as settled with Air Products as of the end of each year. Therefore, they are included in Air Products’ net investment in the Annual Combined Financial Statements.

Non-controlling Interests

We consolidate investments that we control but do not wholly own. The Annual Combined Financial Statements include all assets, liabilities, revenues, and expenses of our joint venture in Taiwan for which we have a 74% ownership interest during the periods presented in the Annual Combined Financial Statements. The ownership interests held by third party non-controlling partners are presented as non-controlling interests in our annual combined balance sheets. Any net income or loss attributed to the non-controlling partners is presented as such in the combined income statements. The activity for non-controlling interests for the years ended September 30, 2016, 2015 and 2014 is presented in the annual combined statements of changes in Air Products’ invested equity and non-controlling interests.

Cash and Cash Items

Cash and cash items generally include cash, time deposits, and certificates of deposit acquired with an original maturity of three months or less for our foreign entities. Cash is managed centrally and most cash generated by our business was remitted to Air Products. Such centralized cash management transactions relating to our business are reflected through Air Products’ net investment. Accordingly, none of the centrally managed cash at the Air Products’ corporate level has been reflected in our Annual Combined Financial Statements.

Restricted Cash

Restricted cash consists of cash restricted for payment to Air Products subsequent to the Separation.

Trade Receivables, net

Trade receivables comprise amounts owed to us through our operating activities and are presented net of allowances for doubtful accounts. The allowances for doubtful accounts represent estimated uncollectible receivables associated with potential customer defaults on contractual obligations. A provision for customer defaults is made on a general formula basis when it is determined that the risk of some default is probable and estimable but cannot yet be associated with specific customers. The assessment of the likelihood of customer defaults is based on various factors, including the length of time the receivables are past due, historical experience, and existing economic conditions. The allowance also includes amounts for certain customers where a risk of default has been specifically identified, considering factors such as the financial condition of the customer and customer disputes over contractual terms and conditions. Allowance for doubtful accounts were $0.8 million and $0.8 million as of fiscal year end September 30, 2016 and 2015, respectively. Provisions to the allowance for doubtful accounts charged against income were not material in fiscal 2016, 2015, and 2014.

Inventories

Inventories are stated at the lower of cost or market. We write down our inventories for estimated obsolescence or unmarketable inventory based upon assumptions about future demand and market conditions.

We utilize the last-in, first-out (“LIFO”) method for determining the cost of inventories in the United States. Inventories outside of the United States are accounted for on the first-in, first-out (“FIFO”) method, as the LIFO method is not generally permitted in the foreign jurisdictions we operate.

Equity Investments

The equity method of accounting is used when we exercise significant influence but do not have operating control, generally assumed to be 20% to 50% ownership. Under the equity method, original investments are recorded at cost and adjusted by our share of undistributed earnings or losses of these companies. Equity investments are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the investment may not be recoverable. The Annual Combined Financial Statements include our investment in and proportionate share of the income from our 20% owned equity affiliate, Daido Air Products Electronics, Inc. During the first quarter of 2016, we sold our investment in this affiliate. Refer to Note 6, “Sale of Equity Affiliate”, for additional information.

Plant and Equipment

Plant and equipment is stated at cost less accumulated depreciation. Construction costs, labor, and applicable overhead related to installations are capitalized. Expenditures for additions and improvements that extend the lives or increase the capacity of plant assets are capitalized. The costs of maintenance and repairs of plant and equipment are charged to expense as incurred.

Fully depreciated assets are retained in the gross plant and equipment and accumulated depreciation accounts until they are removed from service. In the case of disposals, assets and related depreciation are removed from the accounts, and the net amounts, less proceeds from disposal, are included in income.

Impairment of Long-Lived Assets

Long-lived assets are grouped for impairment testing at the lowest level for which there are identifiable cash flows that are largely independent of the cash flows of other assets and liabilities and are evaluated for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset group may not be recoverable. We assess recoverability by comparing the carrying amount of the asset group to estimated undiscounted future cash flows expected to be generated by the asset group. If an asset group is considered impaired, the impairment loss to be recognized is measured as the amount by which the asset group’s carrying amount exceeds its fair value. Long-lived assets to be sold are reported at the lower of carrying amount or fair value less cost to sell.

Goodwill

Business combinations are accounted for using the acquisition method. The purchase price is allocated to the assets acquired and liabilities assumed based on their estimated fair market values. Any excess purchase price over the fair market value of the net assets acquired, including identified intangibles, is recorded as goodwill. Preliminary purchase price allocations are made at the date of acquisition and finalized when information needed to affirm underlying estimates is obtained, within a maximum allocation period of one year.

Goodwill is subject to impairment testing at least annually. In addition, goodwill is tested more frequently if a change in circumstances or the occurrence of events indicates that potential impairment exists.

Intangible Assets

Intangible assets with determinable lives primarily consist of customer relationships and purchased patents and technology. The cost of intangible assets with determinable lives is amortized on a straight-line basis over the estimated period of economic benefit. Amortizable lives are adjusted whenever there is a change in the estimated period of economic benefit. No residual value is estimated for intangible assets.

Retirement Benefits

Air Products sponsors defined benefit pension plans, defined contribution plans, and other post-employment benefit plans that are shared amongst its businesses. Participation of our employees in these plans is reflected in the Annual Combined Financial Statements as though Versum participates in a multiemployer plan with Air Products. A proportionate share of cost is reflected in these Annual Combined Financial Statements, primarily within selling and administrative expenses. Assets and liabilities of such plans are retained by Air Products.

Air Products’ Net Investment

Air Products’ net investment in our business is presented as “Air Products’ net investment” in lieu of stockholders’ equity, as a stand-alone legal and capital structure did not exist for the historical periods presented.

Earnings Per Share

Versum earnings per share for 2016, 2015 and 2014 were calculated using the shares that were distributed to Air Products stockholders immediately following the Separation. For periods prior to the Separation it is assumed that there are no dilutive equity instruments as there were no equity awards in Versum outstanding prior to the Separation.