Accounting Policies (Policies)	6 Months Ended
Jun. 30, 2019
Accounting Policies [Abstract]
Basis Of Accounting	The interim consolidated financial statements include the accounts of Allegheny Technologies Incorporated and its subsidiaries. Unless the context requires otherwise, “Allegheny Technologies”, “ATI” and “the Company” refer to Allegheny Technologies Incorporated and its subsidiaries. These unaudited consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles for interim financial information and with the instructions for Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and note disclosures required by U.S. generally accepted accounting principles for complete financial statements. In management’s opinion, all adjustments (which include only normal recurring adjustments) considered necessary for a fair presentation have been included. Certain prior year amounts have been reclassified in order to conform with fiscal year 2019 presentation. These unaudited consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Company’s 2018 Annual Report on Form 10-K. The results of operations for these interim periods are not necessarily indicative of the operating results for any future period. The December 31, 2018 financial information has been derived from the Company’s audited consolidated financial statements.
New Accounting Pronouncements Adopted	New Accounting Pronouncements Adopted In January 2019, the Company adopted changes issued by the Financial Accounting Standards Board (FASB) related to leases. See Note 9 for further explanation related to this adoption, including all newly expanded disclosure requirements.
New Accounting Pronouncements Not Yet Adopted	Pending Accounting Pronouncements In August 2018, the FASB issued new disclosure guidance on fair value measurement. This new guidance modifies the disclosure requirements on fair value measurements, including removal and modifications of various current disclosures as well as some additional disclosure requirements for Level 3 fair value measurements. Some of these disclosure changes must be applied prospectively while others retrospectively depending on requirement. This guidance is required to be adopted by the Company beginning in fiscal year 2020 with early adoption permitted. The Company does not plan to early adopt this guidance. The adoption of these changes is not expected to have an impact on the Company’s consolidated financial statements other than disclosures. In June 2016, the FASB added a new impairment model (known as the current expected credit loss (CECL) model) that is based on expected losses rather than incurred losses. Under the new guidance, an entity recognizes as an allowance its estimate of expected credit losses. The CECL model applies to trade receivables, other receivables, and most debt instruments. The CECL model does not have a minimum threshold for recognition of impairment losses, and entities will need to measure expected credit losses on assets that have a low risk of loss. This guidance is required to be adopted by the Company beginning in fiscal year 2020. Management is currently evaluating the potential impact of these changes on the Company’s consolidated financial statements.
Inventory	Inventories are stated at the lower of cost (last-in, first-out (LIFO), first-in, first-out (FIFO), and average cost methods) or market. Most of the Company’s inventory is valued utilizing the LIFO costing methodology. Inventory of the Company’s non-U.S. operations is valued using average cost or FIFO methods. Due to deflationary impacts primarily related to raw materials, the carrying value of the Company’s inventory as valued on LIFO exceeds current replacement cost, and based on a lower of cost or market value analysis, the Company maintains NRV inventory valuation reserves to adjust carrying value of LIFO inventory to current replacement cost.
Leases	On January 1, 2019 the Company adopted Accounting Standards Codification Topic 842 (ASC 842), Leases. This new guidance requires a lessee to recognize assets and liabilities on the balance sheet for all leases, with the result being the recognition of a right of use (ROU) asset and a lease liability. The lease liability is equal to the present value of the minimum lease payments for the term of the lease, including any optional renewal periods determined to be reasonably certain to be exercised, using the discount rate determined at lease commencement. This discount rate is the rate implicit in the lease, if known; otherwise, the incremental borrowing rate (IBR) for the expected lease term is used. The Company’s IBRs approximate the rate the Company would have to pay to borrow on a collateralized basis over a similar term at lease inception. The ROU asset is equal to the initial measurement of the lease liability plus any lease payments made to the lessor at or before the commencement date and any unamortized initial direct costs incurred by the lessee, less any unamortized lease incentives received. The Company has lease contracts for real property and machinery and equipment, primarily for mobile, office and information technology equipment. At inception of a contract, the Company determines whether the contract is or contains a lease. If the Company has a right to obtain substantially all of the economic benefits from the use of the identified asset and the right to direct the use of the asset, then the contract contains a lease. Several of the Company’s real property lease contracts include options to extend the lease term; however, the Company currently has not included the renewal options for these leases in the ROU asset and lease liability because the likelihood of renewal was not determined to be reasonably certain. The Company will reassess the likelihood of renewal on at least an annual basis. In addition, several real property leases include variable lease payments, for items such as common area maintenance and utilities, which are expensed as incurred as variable lease expense. There are two types of leases, operating leases and finance leases. Lease classification is determined at lease commencement. The criteria used for a lease to be classified as a finance lease is generally consistent with the criteria under the previous lease accounting guidance, ASC 840, for capital leases. All other leases not meeting the finance lease criteria are classified as operating leases. Operating lease expense is recognized on a straight-line basis on the consolidated statement of income. Finance leases have front-loaded expense recognition which is reported as amortization expense and interest expense on the consolidated statement of income. ROU assets for operating leases are classified in other long-term assets, and ROU assets for finance leases are classified in property, plant and equipment on the consolidated balance sheet. For operating leases, short-term lease liabilities are classified in other current liabilities, and long-term lease liabilities are classified in other long-term liabilities on the consolidated balance sheet. For finance leases, short-term lease liabilities are classified in short-term debt, and long-term lease liabilities are classified in long-term debt on the consolidated balance sheet. On the cash flow statement, payments for operating leases are classified as operating activities. Payments for finance leases are classified as a financing activity, with the exception of the interest component of the payment which is classified as an operating activity.
Derivatives	For derivative financial instruments that are designated as cash flow hedges, the gain or loss on the derivative is reported as a component of other comprehensive income (OCI) and reclassified into earnings in the same period or periods during which the hedged item affects earnings. For derivative financial instruments that are designated as fair value hedges, changes in the fair value of these derivatives are recognized in current period results and are reported as changes within accrued liabilities and other on the consolidated statements of cash flows. There were no outstanding fair value hedges as of June 30, 2019. The Company did not use net investment hedges for the periods presented. The effects of derivative instruments in the tables below are presented net of related income taxes, excluding any impacts of changes to income tax valuation allowances effecting results of operations or other comprehensive income, when applicable (see Note 17 for further explanation). As part of its risk management strategy, the Company, from time-to-time, utilizes derivative financial instruments to manage its exposure to changes in raw material prices, energy costs, foreign currencies, and interest rates. In accordance with applicable accounting standards, the Company accounts for most of these contracts as hedges. The Company sometimes uses futures and swap contracts to manage exposure to changes in prices for forecasted purchases of raw materials, such as nickel, and natural gas. Under these contracts, which are generally accounted for as cash flow hedges, the price of the item being hedged is fixed at the time that the contract is entered into, and the Company is obligated to make or receive a payment equal to the net change between this fixed price and the market price at the date the contract matures. The majority of ATI’s products are sold utilizing raw material surcharges and index mechanisms. However, as of June 30, 2019, the Company had entered into financial hedging arrangements, primarily at the request of its customers, related to firm orders, for an aggregate notional amount of approximately 10 million pounds of nickel with hedge dates through 2023. The aggregate notional amount hedged is approximately 10% of a single year’s estimated nickel raw material purchase requirements. At June 30, 2019, the outstanding financial derivatives used to hedge the Company’s exposure to energy cost volatility included natural gas cost hedges. At June 30, 2019, the Company hedged approximately 70% of the Company’s forecasted domestic requirements for natural gas for the remainder of 2019, approximately 60% for 2020, and approximately 30% for 2021. While the majority of the Company’s direct export sales are transacted in U.S. dollars, foreign currency exchange contracts are used, from time-to-time, to limit transactional exposure to changes in currency exchange rates for those transactions denominated in a non-U.S. currency. The Company sometimes purchases foreign currency forward contracts that permit it to sell specified amounts of foreign currencies expected to be received from its export sales for pre-established U.S. dollar amounts at specified dates. The forward contracts are denominated in the same foreign currencies in which export sales are denominated. These contracts are designated as hedges of the variability in cash flows of a portion of the forecasted future export sales transactions which otherwise would expose the Company to foreign currency risk, primarily euro. In addition, the Company may also designate cash balances held in foreign currencies as hedges of forecasted foreign currency transactions. At June 30, 2019, the Company held euro forward sales contracts designated as cash flow hedges with a notional value of approximately 24 million euro with maturity dates through December 2019. The Company may enter into derivative interest rate contracts to maintain a reasonable balance between fixed- and floating-rate debt. At June 30, 2019, the Company has a $50 million floating-for-fixed interest rate swap maturing in January 2021, which converts half of the Term Loan to a 5.44% fixed interest rate. The interest rate swap is designated as a cash flow hedge of the Company’s exposure to the variability of the payment of interest on a portion of its Term Loan borrowings. There are no credit risk-related contingent features in the Company’s derivative contracts, and the contracts contained no provisions under which the Company has posted, or would be required to post, collateral. The counterparties to the Company’s derivative contracts are substantial and creditworthy commercial banks that are recognized market makers. The Company controls its credit exposure by diversifying across multiple counterparties and by monitoring credit ratings and credit default swap spreads of its counterparties. The Company also enters into master netting agreements with counterparties when possible.
Retirement Benefits	The Company has defined contribution retirement plans or defined benefit pension plans covering substantially all employees. Company contributions to defined contribution retirement plans are generally based on a percentage of eligible pay or based on hours worked. Benefits under the defined benefit pension plans are generally based on years of service and/or final average pay. The Company funds the U.S. pension plans in accordance with the Employee Retirement Income Security Act of 1974, as amended, and the Internal Revenue Code (IRC). The Company also sponsors several postretirement plans covering certain collectively-bargained salaried and hourly employees. The plans provide health care and life insurance benefits for eligible retirees. In most retiree health care plans, Company contributions towards premiums are capped based on the cost as of a certain date, thereby creating a defined contribution.
Commitments And Contingencies	Environmental liabilities are recorded when the Company’s liability is probable and the costs are reasonably estimable. In many cases, however, the Company is not able to determine whether it is liable or, if liability is probable, to reasonably estimate the loss or range of loss. Estimates of the Company’s liability remain subject to additional uncertainties, including the nature and extent of site contamination, available remediation alternatives, the extent of corrective actions that may be required, and the number, participation, and financial condition of other potentially responsible parties (PRPs). The Company adjusts its accruals to reflect new information as appropriate. Future adjustments could have a material adverse effect on the Company’s consolidated results of operations in a given period, but the Company cannot reliably predict the amounts of such future adjustments.

Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2019

The interim consolidated financial statements include the accounts of Allegheny Technologies Incorporated and its subsidiaries. Unless the context requires otherwise, “Allegheny Technologies”, “ATI” and “the Company” refer to Allegheny Technologies Incorporated and its subsidiaries.

These unaudited consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles for interim financial information and with the instructions for Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and note disclosures required by U.S. generally accepted accounting principles for complete financial statements. In management’s opinion, all adjustments (which include only normal recurring adjustments) considered necessary for a fair presentation have been included. Certain prior year amounts have been reclassified in order to conform with fiscal year 2019 presentation. These unaudited consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Company’s 2018 Annual Report on Form 10-K. The results of operations for these interim periods are not necessarily indicative of the operating results for any future period. The December 31, 2018 financial information has been derived from the Company’s audited consolidated financial statements.

New Accounting Pronouncements Adopted

In January 2019, the Company adopted changes issued by the Financial Accounting Standards Board (FASB) related to leases. See Note 9 for further explanation related to this adoption, including all newly expanded disclosure requirements.

New Accounting Pronouncements Not Yet Adopted

Pending Accounting Pronouncements

In August 2018, the FASB issued new disclosure guidance on fair value measurement. This new guidance modifies the disclosure requirements on fair value measurements, including removal and modifications of various current disclosures as well as some additional disclosure requirements for Level 3 fair value measurements. Some of these disclosure changes must be applied prospectively while others retrospectively depending on requirement. This guidance is required to be adopted by the Company beginning in fiscal year 2020 with early adoption permitted. The Company does not plan to early adopt this guidance. The adoption of these changes is not expected to have an impact on the Company’s consolidated financial statements other than disclosures.

In June 2016, the FASB added a new impairment model (known as the current expected credit loss (CECL) model) that is based on expected losses rather than incurred losses. Under the new guidance, an entity recognizes as an allowance its estimate of expected credit losses. The CECL model applies to trade receivables, other receivables, and most debt instruments. The CECL model does not have a minimum threshold for recognition of impairment losses, and entities will need to measure expected credit losses on assets that have a low risk of loss. This guidance is required to be adopted by the Company beginning in fiscal year 2020. Management is currently evaluating the potential impact of these changes on the Company’s consolidated financial statements.

Inventory

Inventories are stated at the lower of cost (last-in, first-out (LIFO), first-in, first-out (FIFO), and average cost methods) or market. Most of the Company’s inventory is valued utilizing the LIFO costing methodology. Inventory of the Company’s non-U.S. operations is valued using average cost or FIFO methods. Due to deflationary impacts primarily related to raw materials, the carrying value of the Company’s inventory as valued on LIFO exceeds current replacement cost, and based on a lower of cost or market value analysis, the Company maintains NRV inventory valuation reserves to adjust carrying value of LIFO inventory to current replacement cost.

Leases

On January 1, 2019 the Company adopted Accounting Standards Codification Topic 842 (ASC 842), Leases. This new guidance requires a lessee to recognize assets and liabilities on the balance sheet for all leases, with the result being the recognition of a right of use (ROU) asset and a lease liability. The lease liability is equal to the present value of the minimum lease payments for the term of the lease, including any optional renewal periods determined to be reasonably certain to be exercised, using the discount rate determined at lease commencement. This discount rate is the rate implicit in the lease, if known; otherwise, the incremental borrowing rate (IBR) for the expected lease term is used. The Company’s IBRs approximate the rate the Company would have to pay to borrow on a collateralized basis over a similar term at lease inception. The ROU asset is equal to the initial measurement of the lease liability plus any lease payments made to the lessor at or before the commencement date and any unamortized initial direct costs incurred by the lessee, less any unamortized lease incentives received.

The Company has lease contracts for real property and machinery and equipment, primarily for mobile, office and information technology equipment. At inception of a contract, the Company determines whether the contract is or contains a lease. If the Company has a right to obtain substantially all of the economic benefits from the use of the identified asset and the right to direct the use of the asset, then the contract contains a lease. Several of the Company’s real property lease contracts include options to extend the lease term; however, the Company currently has not included the renewal options for these leases in the ROU asset and lease liability because the likelihood of renewal was not determined to be reasonably certain. The Company will reassess the likelihood of renewal on at least an annual basis. In addition, several real property leases include variable lease payments, for items such as common area maintenance and utilities, which are expensed as incurred as variable lease expense.

There are two types of leases, operating leases and finance leases. Lease classification is determined at lease commencement. The criteria used for a lease to be classified as a finance lease is generally consistent with the criteria under the previous lease accounting guidance, ASC 840, for capital leases. All other leases not meeting the finance lease criteria are classified as operating leases. Operating lease expense is recognized on a straight-line basis on the consolidated statement of income. Finance leases have front-loaded expense recognition which is reported as amortization expense and interest expense on the consolidated statement of income. ROU assets for operating leases are classified in other long-term assets, and ROU assets for finance leases are classified in property, plant and equipment on the consolidated balance sheet. For operating leases, short-term lease liabilities are classified in other current liabilities, and long-term lease liabilities are classified in other long-term liabilities on the consolidated balance sheet. For finance leases, short-term lease liabilities are classified in short-term debt, and long-term lease liabilities are classified in long-term debt on the consolidated balance sheet. On the cash flow statement, payments for operating leases are classified as operating activities. Payments for finance leases are classified as a financing activity, with the exception of the interest component of the payment which is classified as an operating activity.

Derivatives

For derivative financial instruments that are designated as cash flow hedges, the gain or loss on the derivative is reported as a component of other comprehensive income (OCI) and reclassified into earnings in the same period or periods during which the hedged item affects earnings. For derivative financial instruments that are designated as fair value hedges, changes in the fair value of these derivatives are recognized in current period results and are reported as changes within accrued liabilities and other on the consolidated statements of cash flows. There were no outstanding fair value hedges as of June 30, 2019. The Company did not use net investment hedges for the periods presented. The effects of derivative instruments in the tables below are presented net of related income taxes, excluding any impacts of changes to income tax valuation allowances effecting results of operations or other comprehensive income, when applicable (see Note 17 for further explanation).

As part of its risk management strategy, the Company, from time-to-time, utilizes derivative financial instruments to manage its exposure to changes in raw material prices, energy costs, foreign currencies, and interest rates. In accordance with applicable accounting standards, the Company accounts for most of these contracts as hedges.

The Company sometimes uses futures and swap contracts to manage exposure to changes in prices for forecasted purchases of raw materials, such as nickel, and natural gas. Under these contracts, which are generally accounted for as cash flow hedges, the price of the item being hedged is fixed at the time that the contract is entered into, and the Company is obligated to make or receive a payment equal to the net change between this fixed price and the market price at the date the contract matures.

The majority of ATI’s products are sold utilizing raw material surcharges and index mechanisms. However, as of June 30, 2019, the Company had entered into financial hedging arrangements, primarily at the request of its customers, related to firm orders, for an aggregate notional amount of approximately 10 million pounds of nickel with hedge dates through 2023. The aggregate notional amount hedged is approximately 10% of a single year’s estimated nickel raw material purchase requirements.

At June 30, 2019, the outstanding financial derivatives used to hedge the Company’s exposure to energy cost volatility included natural gas cost hedges. At June 30, 2019, the Company hedged approximately 70% of the Company’s forecasted domestic requirements for natural gas for the remainder of 2019, approximately 60% for 2020, and approximately 30% for 2021.

While the majority of the Company’s direct export sales are transacted in U.S. dollars, foreign currency exchange contracts are used, from time-to-time, to limit transactional exposure to changes in currency exchange rates for those transactions denominated in a non-U.S. currency. The Company sometimes purchases foreign currency forward contracts that permit it to sell specified amounts of foreign currencies expected to be received from its export sales for pre-established U.S. dollar amounts at specified dates. The forward contracts are denominated in the same foreign currencies in which export sales are denominated. These contracts are designated as hedges of the variability in cash flows of a portion of the forecasted future export sales transactions which otherwise would expose the Company to foreign currency risk, primarily euro. In addition, the Company may also designate cash balances held in foreign currencies as hedges of forecasted foreign currency transactions. At June 30, 2019, the Company held euro forward sales contracts designated as cash flow hedges with a notional value of approximately 24 million euro with maturity dates through December 2019.

The Company may enter into derivative interest rate contracts to maintain a reasonable balance between fixed- and floating-rate debt. At June 30, 2019, the Company has a $50 million floating-for-fixed interest rate swap maturing in January 2021, which converts half of the Term Loan to a 5.44% fixed interest rate. The interest rate swap is designated as a cash flow hedge of the Company’s exposure to the variability of the payment of interest on a portion of its Term Loan borrowings.

There are no credit risk-related contingent features in the Company’s derivative contracts, and the contracts contained no provisions under which the Company has posted, or would be required to post, collateral. The counterparties to the Company’s derivative contracts are substantial and creditworthy commercial banks that are recognized market makers. The Company controls its credit exposure by diversifying across multiple counterparties and by monitoring credit ratings and credit default swap spreads of its counterparties. The Company also enters into master netting agreements with counterparties when possible.

Retirement Benefits

The Company has defined contribution retirement plans or defined benefit pension plans covering substantially all employees. Company contributions to defined contribution retirement plans are generally based on a percentage of eligible pay or based on hours worked. Benefits under the defined benefit pension plans are generally based on years of service and/or final average pay. The Company funds the U.S. pension plans in accordance with the Employee Retirement Income Security Act of 1974, as amended, and the Internal Revenue Code (IRC).

The Company also sponsors several postretirement plans covering certain collectively-bargained salaried and hourly employees. The plans provide health care and life insurance benefits for eligible retirees. In most retiree health care plans, Company contributions towards premiums are capped based on the cost as of a certain date, thereby creating a defined contribution.

Commitments And Contingencies

Environmental liabilities are recorded when the Company’s liability is probable and the costs are reasonably estimable. In many cases, however, the Company is not able to determine whether it is liable or, if liability is probable, to reasonably estimate the loss or range of loss. Estimates of the Company’s liability remain subject to additional uncertainties, including the nature and extent of site contamination, available remediation alternatives, the extent of corrective actions that may be required, and the number, participation, and financial condition of other potentially responsible parties (PRPs). The Company adjusts its accruals to reflect new information as appropriate. Future adjustments could have a material adverse effect on the Company’s consolidated results of operations in a given period, but the Company cannot reliably predict the amounts of such future adjustments.