Metallus (MTUS) 10-K 25 Feb 20 2019 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Feb. 15, 2020	Jun. 30, 2019
Document and Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Registrant Name	TimkenSteel Corporation
Entity Central Index Key	0001598428
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Current Reporting Status	Yes
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Shell Company	false
Entity Public Float			$ 337,525,844
Entity Common Stock, Shares Outstanding		44,821,588

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Net sales	$ 1,208,800,000	$ 1,610,600,000	$ 1,329,200,000
Cost of products sold	1,186,200,000	1,484,000,000	1,248,900,000
Gross Profit	22,600,000	126,600,000	80,300,000
Selling, general and administrative expenses	91,800,000	98,200,000	90,500,000
Restructuring charges	8,600,000	0	0
Impairment charges and loss on sale or disposal of assets	9,300,000	900,000	700,000
Interest expense	15,700,000	17,100,000	14,800,000
Other income (expense), net	(23,300,000)	(18,600,000)	(4,100,000)
Income (Loss) Before Income Taxes	(126,100,000)	(8,200,000)	(29,800,000)
Provision (benefit) for income taxes	(16,100,000)	1,800,000	1,500,000
Net Income (Loss)	$ (110,000,000)	$ (10,000,000)	$ (31,300,000)
Per Share Data:
Basic earnings (loss) per share (in dollars per share)	$ (2.46)	$ (0.22)	$ (0.70)
Diluted earnings (loss) per share (in dollars per share)	$ (2.46)	$ (0.22)	$ (0.70)

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (10)	$ (31.3)
Other comprehensive income (loss), net of tax of $16.7 million in 2019:
Foreign currency translation adjustments	(1.4)	1.1
Pension and postretirement liability adjustments	0.1	0.7
Other comprehensive income (loss), net of tax	(1.3)	1.8
Comprehensive Income (Loss), net of tax	$ (11.3)	$ (29.5)

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Current Assets
Cash and cash equivalents	$ 27.1	$ 21.6
Accounts receivable, net of allowances (2019 - $1.5 million; 2018 - $1.7 million)	77.5	163.4
Inventories, net	281.9	374.5
Deferred charges and prepaid expenses	3.3	3.5
Assets held for sale	4.1	0
Other current assets	7.8	6.1
Total Current Assets	401.7	569.1
Property, Plant and Equipment, Net	626.4	674.4
Operating lease right-of-use assets	14.3
Pension assets	25.2	10.5
Intangible assets, net	14.3	17.8
Other non-current assets	3.3	3.5
Total Assets	1,085.2	1,275.3
Current Liabilities
Accounts payable	69.3	160.6
Salaries, wages and benefits	13.9	36.8
Accrued pension and postretirement costs	3	3
Current operating lease liabilities	6.2	0
Other current liabilities	19.9	20.4
Total Current Liabilities	112.3	220.8
Non-Current Liabilities
Convertible notes, net	78.6	74.1
Credit Agreement	90	115
Non-current operating lease liabilities	8.2
Accrued pension and postretirement costs	222.1	240
Deferred income taxes	0.9	0.8
Other non-current liabilities	10	11.7
Total Liabilities	522.1	662.4
Shareholders’ Equity
Preferred shares, without par value; authorized 10.0 million shares, none issued	0	0
Common shares, without par value; authorized 200.0 million shares; issued 2019 and 2018 - 45.7 million shares	0	0
Additional paid-in capital	844.8	846.3
Retained deficit	(301.5)	(191.5)
Treasury shares - 2019 - 0.9 million; 2018 - 1.1 million	(24.9)	(33)
Accumulated other comprehensive loss	44.7	(8.9)
Total Shareholders’ Equity	563.1	612.9
Total Liabilities and Shareholders’ Equity	$ 1,085.2	$ 1,275.3

Consolidated Balance Sheets (_2

Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Allowances for accounts receivable	$ 1.5	$ 1.7
Preferred shares, authorized (in shares)	10,000,000	10,000,000
Preferred shares, issued (in shares)	0	0
Common shares, authorized (in shares)	200,000,000	200,000,000
Common shares, issued (in shares)	45,700,000	45,700,000
Treasury shares (in shares)	900,000	1,100,000

Consolidated Statements of Shar

Consolidated Statements of Shareholder's Equity (Unaudited) - USD ($) $ in Millions	Total	Common Shares Outstanding	Additional Paid-in Capital	Retained Deficit	Treasury Shares	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2016		44,228,213
Beginning balance at Dec. 31, 2016	$ 597.4		$ 845.6	$ (193.9)	$ (44.9)	$ (9.4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(31.3)
Other comprehensive income (loss)	1.8					1.8
Stock-based compensation expense	6.5		6.5
Stock option activity	0.2		0.2
Issuance of treasury shares (in shares)		300,130
Issuance of treasury shares	0		(8.6)	(0.3)	8.9
Shares surrendered for taxes (in shares		(82,596)
Shares surrendered for taxes	(1.4)				(1.4)
Ending balance (in shares) at Dec. 31, 2017		44,445,747
Ending balance at Dec. 31, 2017	616.7		843.7	(182)	(37.4)	(7.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(10)
Other comprehensive income (loss)	(1.3)					(1.3)
Stock-based compensation expense	7.3		7.3
Stock option activity	0.2		0.2
Issuance of treasury shares (in shares)		176,454
Issuance of treasury shares	0		(4.9)	(0.2)	5.1
Shares surrendered for taxes (in shares		(37,533)
Shares surrendered for taxes	(0.7)				(0.7)
Ending balance (in shares) at Dec. 31, 2018		44,584,668
Ending balance at Dec. 31, 2018	612.9		846.3	(191.5)	(33)	(8.9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(110)			(110)
Other comprehensive income (loss)	53.6					53.6
Stock-based compensation expense	7.4		7.4
Stock option activity	0.2		0.2
Issuance of treasury shares (in shares)		321,739
Issuance of treasury shares	0		(9.1)		9.1
Shares surrendered for taxes (in shares		(86,254)
Shares surrendered for taxes	(1)				(1)
Ending balance (in shares) at Dec. 31, 2019		44,820,153
Ending balance at Dec. 31, 2019	$ 563.1		$ 844.8	$ (301.5)	$ (24.9)	$ 44.7

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Activities
Net income (loss)	$ (110)	$ (10)	$ (31.3)
Adjustments to reconcile net loss to net cash provided (used) by operating activities:
Depreciation and amortization	73.5	73	74.9
Amortization of deferred financing fees and debt discount	5.1	5.5	4
Impairment charges and loss on sale or disposal of assets	9.3	0.9	1.6
Deferred income taxes	(16.6)	0.8	(0.3)
Stock-based compensation expense	7.4	7.3	6.5
Pension and postretirement expense (benefit), net	41.6	37.4	24.7
Pension and postretirement contributions and payments	(3.8)	(13.1)	(4.3)
Changes in operating assets and liabilities:
Accounts receivable, net	85.9	(13.6)	(58.2)
Inventories, net	92.6	(94.5)	(72.3)
Accounts payable	(87.7)	24.4	45.7
Other accrued expenses	(26)	(3.8)	18.3
Deferred charges and prepaid expenses	0.2	0.4	(0.5)
Other, net	(1.2)	3.8	(0.7)
Net Cash Provided (Used) by Operating Activities	70.3	18.5	8.1
Investing Activities
Capital expenditures	(38)	(40)	(33)
Proceeds from disposals of property, plant and equipment	0	1	0
Net Cash Provided (Used) by Investing Activities	(38)	(39)	(33)
Financing Activities
Proceeds from exercise of stock options	0.2	0.2	0.2
Shares surrendered for employee taxes on stock compensation	(1)	(0.7)	(1.4)
Refunding Bonds repayments	0	(30.2)	0
Repayments on credit agreements	(65)	(105)	(5)
Borrowings on credit agreements	40	155	30
Debt issuance costs	(1)	(1.7)	0
Net Cash Provided by Financing Activities	(26.8)	17.6	23.8
Increase (Decrease) in Cash and Cash Equivalents	5.5	(2.9)	(1.1)
Cash and cash equivalents at beginning of period	21.6	24.5	25.6
Cash and Cash Equivalents at End of Period	$ 27.1	$ 21.6	$ 24.5

Basis of Presentation

Basis of Presentation	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation TimkenSteel Corporation (the Company or TimkenSteel) manufactures alloy steel, as well as carbon and micro-alloy steel, with an annual melt capacity of approximately 2 million tons and shipment capacity of 1.5 million tons. TimkenSteel’s portfolio includes special bar quality (SBQ) bars, seamless mechanical tubing (tubes), value-added solutions such as precision steel components, and billets. In addition, TimkenSteel supplies machining and thermal treatment services and manages raw material recycling programs, which are used as a feeder system for the Company’s melt operations. The Company’s products and services are used in a diverse range of demanding applications in the following market sectors: automotive; oil and gas; industrial equipment; mining; construction; rail; defense; heavy truck; agriculture; power generation; and oil country tubular goods (OCTG);. The SBQ bar, tube, and billet production processes take place at the Company’s Canton, Ohio manufacturing location. This location accounts for all of the SBQ bars, seamless mechanical tubes and billets the Company produces and includes three manufacturing facilities: the Faircrest, Harrison, and Gambrinus facilities. TimkenSteel’s value-added solutions production processes take place at three downstream manufacturing facilities: TimkenSteel Material Services (Houston, Texas), Tryon Peak (Columbus, North Carolina), and St. Clair (Eaton, Ohio). Many of the production processes are integrated, and the manufacturing facilities produce products that are sold in all of the Company’s market sectors. As a result, investments in the Company’s facilities and resource allocation decisions affecting the Company’s operations are designed to benefit the overall business, not any specific aspect of the business. In the fourth quarter of 2019, our Board of Directors approved a plan to close our TimkenSteel Material Services facility during the first quarter of 2020. Basis of Consolidation: The Consolidated Financial Statements include the consolidated assets, liabilities, revenues and expenses related to TimkenSteel as of December 31, 2019, 2018 and 2017. All significant intercompany accounts and transactions within TimkenSteel have been eliminated in the preparation of the Consolidated Financial Statements. Use of Estimates: The preparation of these Consolidated Financial Statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the amounts reported in the Consolidated Financial Statements and accompanying notes. These estimates and assumptions are reviewed and updated regularly to reflect recent experience. Presentation: Certain items previously reported in specific financial statement captions have been reclassified to conform to the fiscal 2019 presentation. Change in Accounting Principle: During the fourth quarter of 2019, TimkenSteel elected to change its method for valuing its inventories that previously used the last-in, first-out (LIFO) method to the first-in, first-out (FIFO) method. Total inventories accounted for under the LIFO method represented approximately 70% of the Company's total inventories prior to this change in method. The Company believes that the FIFO method is preferable as it improves comparability with our peers, more closely resembles the physical flow of our inventory, and aligns with how the Company internally manages the business. The effects of the change in accounting principle from LIFO to FIFO have been retrospectively applied to all periods presented. As a result of the retrospective application of the change in accounting principle, certain financial statement line items in the Company’s consolidated balance sheets as of December 31, 2018 and the consolidated statements of operations, comprehensive income (loss), shareholders’ equity and cash flows for the years ended December 31, 2018 and 2017 were adjusted as necessary. The following table reflects the effect of the change in the accounting principle on the 2019 Consolidated Financial Statements (dollars in million, except per share data): For the Year Ended December 31, 2019 As Computed under LIFO As Reported under FIFO Effect of Change Statement of Operations Cost of products sold $1,160.5 $1,186.2 $25.7 Gross profit 48.3 22.6 (25.7 ) Income (loss) before income taxes (100.4 ) (126.1 ) (25.7 ) Net income (loss) (84.3 ) (110.0 ) (25.7 ) Per Share Data: Basic earnings (loss) per share (1.89 ) (2.46 ) (0.57 ) Diluted earnings (loss) per share (1.89 ) (2.46 ) (0.57 ) For the Year Ended December 31, 2019 As Computed under LIFO As Reported under FIFO Effect of Change Statement of Comprehensive Income (Loss) Net (loss) income ($84.3 ) ($110.0 ) ($25.7 ) Comprehensive income (loss), net of tax (30.7 ) (56.4 ) (25.7 ) As of December 31, 2019 As Computed under LIFO As Reported under FIFO Effect of Change Balance Sheet Inventories, net $229.8 $281.9 $52.1 Retained deficit (249.4 ) (301.5 ) (52.1 ) For the Year Ended December 31, 2019 As Computed under LIFO As Reported under FIFO Effect of Change Statement of Cash Flows Net (loss) income ($84.3 ) ($110.0 ) ($25.7 ) Changes in operating assets and liabilities: Inventories, net 66.9 92.6 25.7 The following tables reflect the impact to the financial statement line items as a result of the change in accounting principle for the prior periods presented in the accompanying financial statements (dollars in millions, except per share data): Consolidated Statement of Operations 2018 2017 As Reported Adjustments As Adjusted As Reported Adjustments As Adjusted Cost of products sold $ 1,505.7 $ (21.7 ) $ 1,484.0 $ 1,261.4 $ (12.5 ) $ 1,248.9 Gross profit 104.9 21.7 126.6 67.8 12.5 80.3 Income (loss) before income taxes (29.9 ) 21.7 (8.2 ) (42.3 ) 12.5 (29.8 ) Net income (loss) (31.7 ) 21.7 (10.0 ) (43.8 ) 12.5 (31.3 ) Per Share Data: Basic earnings (loss) per share $ (0.71 ) $ 0.49 $ (0.22 ) $ (0.99 ) $ 0.29 $ (0.70 ) Diluted earnings (loss) per share $ (0.71 ) $ 0.49 $ (0.22 ) $ (0.99 ) $ 0.29 $ (0.70 ) Consolidated Statement of Comprehensive Income (Loss) 2018 2017 As Reported Adjustments As Adjusted As Reported Adjustments As Adjusted Net income (loss) $ (31.7 ) $ 21.7 $ (10.0 ) $ (43.8 ) $ 12.5 $ (31.3 ) Comprehensive income (loss), net of tax (33.0 ) 21.7 (11.3 ) (42.0 ) 12.5 (29.5 ) Consolidated Balance Sheet 2018 As Reported Adjustments As Adjusted Inventories, net $ 296.8 $ 77.7 $ 374.5 Retained deficit (1) (269.2 ) 77.7 (191.5 ) (1) As a result of the accounting change, retained deficit as of January 1, 2017 decreased from $193.9 million , as originally reported using the LIFO method, to $150.4 million using the FIFO method. The change of $43.5 million is reflected as a cumulative change in accounting principle in the Consolidated Statements of Shareholders’ Equity. Consolidated Statement of Cash Flows 2018 2017 As Reported Adjustments As Adjusted As Reported Adjustments As Adjusted Net income (loss) $ (31.7 ) $ 21.7 $ (10.0 ) $ (43.8 ) $ 12.5 $ (31.3 ) Changes in operating assets and liabilities: Inventories, net (72.8 ) (21.7 ) (94.5 ) (59.8 ) (12.5 ) (72.3 )

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
New Accounting Pronouncements and Changes in Accounting Principles	Significant Accounting Policies Revenue Recognition: TimkenSteel recognizes revenue from contracts at a point in time when it has satisfied its performance obligation and the customer obtains control of the goods, at the amount that reflects the consideration the Company expects to receive for those goods. The Company receives and acknowledges purchase orders from its customers, which define the quantity, pricing, payment and other applicable terms and conditions. In some cases, the Company receives a blanket purchase order from its customer, which includes pricing, payment and other terms and conditions, with quantities defined at the time the customer issues periodic releases from the blanket purchase order. Certain contracts contain variable consideration, which primarily consists of rebates that are accounted for in net sales and accrued based on the estimated probability of the requirements being met. Cash Equivalents: TimkenSteel considers all highly liquid investments with a maturity of three months or less when purchased to be cash equivalents. Allowance for Doubtful Accounts: TimkenSteel maintains an allowance for doubtful accounts, which represents an estimate of losses expected from the accounts receivable portfolio, to reduce accounts receivable to their net realizable value. The allowance is based upon historical trends in collections and write-offs, management’s judgment of the probability of collecting accounts and management’s evaluation of business risk. TimkenSteel extends credit to customers satisfying pre-defined credit criteria. TimkenSteel believes it has limited concentration of credit risk due to the diversity of its customer base. Inventories, Net: At December 31, 2019, inventories were stated at the lower of cost or net realizable value. During the fourth quarter of 2019, the Company elected to change its method for valuing its inventories that previously used the LIFO method to the FIFO method. The Company believes that the FIFO method is preferable as it improves comparability with our peers, more closely resembles the physical flow of our inventory, and aligns with how the Company internally manages the business. The remaining inventories, including raw materials, manufacturing supplies inventory as well as international (outside the U.S.) inventories, will continue to be valued using the FIFO or average cost method. The effects of the change in accounting principle from LIFO to FIFO have been retrospectively applied to all periods presented. Refer to “ Note 1 - Basis of Presentation ” for more information. Property, Plant and Equipment, Net: Property, plant and equipment, net are valued at cost less accumulated depreciation. Maintenance and repairs are charged to expense as incurred. The provision for depreciation is computed principally by the straight-line method based upon the estimated useful lives of the assets. The useful lives are approximately 30 years for buildings and three to 20 years for machinery and equipment. Intangible Assets, Net: Intangible assets subject to amortization are amortized on a straight-line method over their legal or estimated useful lives, with useful lives ranging from three to 15 years . In accordance with Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) Topic 350-40, “Internal-Use Software,” (ASC 350-40), TimkenSteel capitalizes certain costs incurred for computer software developed or obtained for internal use. TimkenSteel capitalizes substantially all external costs and qualifying internal costs related to the purchase and implementation of software projects used for business operations. Capitalized software costs primarily include purchased software and external consulting fees. Capitalized software projects are amortized over the estimated useful lives of the software. Long-lived Assets: Long-lived assets (including tangible assets and intangible assets subject to amortization) are reviewed for impairment when events or changes in circumstances have occurred indicating that the carrying value of the assets may not be recoverable. TimkenSteel tests recoverability of long-lived assets at the lowest level for which there are identifiable cash flows that are independent from the cash flows of other assets. Assets and asset groups held and used are measured for recoverability by comparing the carrying amount of the asset or asset group to the sum of future undiscounted net cash flows expected to be generated by the asset or asset group. Assumptions and estimates about future values and remaining useful lives of TimkenSteel’s long-lived assets are complex and subjective. They can be affected by a variety of factors, including external factors such as industry and economic trends and internal factors such as changes in TimkenSteel’s business strategy and internal forecasts. If an asset or asset group is considered to be impaired, the impairment loss that would be recognized is the amount by which the carrying amount of the assets exceeds the fair value of the assets. To determine fair value, TimkenSteel uses internal cash flow estimates discounted at an appropriate interest rate, third party appraisals, as appropriate, and/or market prices of similar assets, when available. Refer to “ Note 6 - Disposition of Non-Core Assets ” and “ Note 11 - Property, Plant and Equipment ” for additional information. Product Warranties: TimkenSteel accrues liabilities for warranties based upon specific claim incidents in accordance with accounting rules relating to contingent liabilities. Should TimkenSteel become aware of a specific potential warranty claim for which liability is probable and reasonably estimable, a specific charge is recorded and accounted for accordingly. TimkenSteel had no significant warranty claims for the years ended December 31, 2019 , 2018 or 2017 . Income Taxes: Deferred tax assets and liabilities are recorded for the future tax consequences attributable to differences between financial statement carrying amounts of existing assets and liabilities and their respective tax bases, as well as net operating loss and tax credit carryforwards. TimkenSteel accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. TimkenSteel recognizes deferred tax assets to the extent TimkenSteel believes these assets are more likely than not to be realized. In making such a determination, TimkenSteel considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If TimkenSteel determines that it would be able to realize deferred tax assets in the future in excess of their net recorded amount, TimkenSteel would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. TimkenSteel records uncertain tax positions in accordance with FASB ASC Topic 740, “Income Taxes” (ASC 740), on the basis of a two-step process whereby (1) TimkenSteel determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position, and (2) for those tax positions that meet the more-likely-than-not recognition threshold, TimkenSteel recognizes the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority. TimkenSteel recognizes interest and penalties related to unrecognized tax benefits within the provision (benefit) for income taxes line in the accompanying Consolidated Statements of Operations. Accrued interest and penalties are included within the related tax liability line in the Consolidated Balance Sheets. During the year ended December 31, 2018, the Company made the accounting policy election to treat taxes related to Global Intangible Low-Taxed Income (GILTI) as a current period expense when incurred. Foreign Currency: Assets and liabilities of subsidiaries are translated at the rate of exchange in effect on the balance sheet date. Income and expenses are translated at the average rates of exchange prevailing during the year. The related translation adjustments are reflected as a separate component of accumulated other comprehensive loss. Gains and losses resulting from foreign currency transactions are included in other expense, net in the Consolidated Statements of Operations. TimkenSteel realized a foreign currency exchange loss of $0.2 million in 2018 and a gain of $0.3 million in 2017 . There were no foreign currency exchange gains or losses in 2019. Pension and Other Postretirement Benefits: TimkenSteel recognizes an overfunded status or underfunded status (e.g., the difference between the fair value of plan assets and the benefit obligations) as either an asset or a liability for its defined benefit pension and other postretirement benefit plans on the Consolidated Balance Sheets. The Company recognizes actuarial gains and losses immediately through net periodic benefit cost in the Consolidated Statements of Operations upon the annual remeasurement at December 31, or on an interim basis as triggering events warrant remeasurement. In addition, the Company uses fair value to account for the value of plan assets. Stock-Based Compensation: TimkenSteel recognizes stock-based compensation expense based on the grant date fair value of the stock-based awards over their required vesting period on a straight-line basis, whether the awards were granted with graded or cliff vesting. Stock options are issued with an exercise price equal to the closing market price of TimkenSteel common shares on the date of grant. The fair value of stock options is determined using a Black-Scholes option pricing model, which incorporates assumptions regarding the expected volatility, the expected option life, the risk-free interest rate and the expected dividend yield. The fair value of stock-based awards that will settle in TimkenSteel common shares, other than stock options, is based on the closing market price of TimkenSteel common shares on the grant date. The fair values of stock-based awards that will settle in cash are remeasured at each reporting period until settlement of the awards. TimkenSteel recognizes all excess tax benefits and tax deficiencies as income tax expense or benefit in the Consolidated Statements of Operations. The excess tax benefits and tax deficiencies are considered discrete items in the reporting period they occur and are not included in the estimate of an entity’s annual effective tax rate. Research and Development: Expenditures for TimkenSteel research and development amounted to $4.1 million for the year ended December 31, 2019, $8.1 million for the year ended December 31, 2018 and $ 8.0 million for the years ended December 31, 2017, and were recorded as a component of selling, general and administrative expenses in the Consolidated Statements of Operations. These expenditures may fluctuate from year to year depending on special projects and the needs of TimkenSteel and its customers. Adoption of New Accounting Standards: The Company adopted the following Accounting Standard Updates (ASU) in the first quarter of 2019, all of which were effective as of January 1, 2019. The adoption of these standards had no impact on the Consolidated Financial Statements or the related Notes to the Consolidated Financial Statements. Standards Adopted Description ASU 2018-07, Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting The standard provides an expanded scope of Topic 718, to include share-based payment transactions for acquiring goods and services from nonemployees. ASU 2018-02, Reporting Comprehensive Income: Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income The standard permits entities to reclassify tax effects stranded in accumulated other comprehensive income as a result of tax reform to retained earnings. ASU 2017-11, Distinguishing Liabilities from Equity; Derivatives and Hedging The standard eliminates the requirement to consider “down round” features when determining whether certain equity-linked financial instruments or embedded features are indexed to an entity’s own stock. On January 1, 2019, the Company adopted ASU 2016-02, “Leases (Topics 842),” which requires lessees to recognize lease liabilities and right-of-use assets on the balance sheet for not only finance (previously capital) leases but also operating leases. The standard also requires additional quantitative and qualitative disclosures. The Company adopted the standard using the modified retrospective transition approach without adjusting comparative periods. The Company elected certain of the practical expedients permitted under the transition guidance within the new standard as follows: • A package of practical expedients to not reassess: ◦ Whether a contract is or contains a lease ◦ Lease classification ◦ Initial direct costs • A practical expedient to not reassess certain land easements The Company has implemented internal controls and lease accounting software to enable the quantification of the expected impact on the Consolidated Balance Sheets and to facilitate the calculations of the related accounting entries and disclosures. Adoption of the lease standard resulted in recognition of right-to-use assets and lease liabilities of $16.0 million as of January 1, 2019. Adoption of the lease standard had no impact on the Company’s debt covenant compliance under its current agreements. Also, the standard did not materially affect the Company’s results of operations or its cash flows. Refer to “ Note 13 - Leases ” for additional information. Accounting Standards Issued But Not Yet Adopted The Company has considered the recent ASUs issued by the Financial Accounting Standards Board summarized below: Standard Pending Adoption Description Effective Date Anticipated Impact ASU 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40) The standard aligns the requirements for capitalizing implementation costs in cloud computing software arrangements with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. January 1, 2020 The Company evaluated the impact of the adoption of this ASU on its results of operations and financial condition and determined that the impact is immaterial. ASU 2018-14, Compensation - Retirement Benefits - Defined Benefit Plans - General (Subtopic 715-20) The standard eliminates, modifies and adds disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. January 1, 2021 The Company is currently evaluating the impact of the adoption of this ASU on its results of operations and financial condition. ASU 2018-13, Fair Value Measurement (Topic 820) The standard eliminates, modifies and adds disclosure requirements for fair value measurements. January 1, 2020 The Company evaluated the impact of the adoption of this ASU on its results of operations and financial condition and determined that the impact is immaterial. ASU 2016-13, Measurement of Credit Losses on Financial Instruments The standard changes how entities will measure credit losses for most financial assets, including trade and other receivables and replaces the current incurred loss approach with an expected loss model. January 1, 2020 The Company evaluated the impact of the adoption of this ASU on its results of operations and financial condition and determined that the impact is immaterial. ASU 2019-12, Income Taxes (Topic 740) The standard simplifies the accounting for income taxes by removing various exceptions. January 1, 2021 The Company is currently evaluating the impact of the adoption of this ASU on its results of operations and financial condition.

Segment Information Segment Inf

Segment Information Segment Information	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Segment Information	Segment Information We conduct our business activities and report financial results as one business segment. The presentation of financial results as one reportable segment is consistent with the way the Company operates its business and is consistent with the manner in which the Chief Operating Decision Maker (CODM) evaluates performance and makes resource and operating decisions for the business as described above. Furthermore, the Company notes that monitoring financial results as one reportable segment helps the CODM manage costs on a consolidated basis, consistent with the integrated nature of the operations. Geographic Information Net sales by geographic area are reported by the country in which the customer is domiciled. Long-lived assets include property, plant and equipment and intangible assets subject to amortization. Long-lived assets by geographic area are reported by the location of the TimkenSteel operations to which the asset is attributed. Year Ended December 31, 2019 2018 2017 Net Sales: United States $1,096.8 $1,456.2 $1,207.7 Foreign 112.0 154.4 121.5 $1,208.8 $1,610.6 $1,329.2 December 31, 2019 2018 Long-lived Assets, net: United States $654.8 $692.0 Foreign 0.2 0.2 $655.0 $692.2

Revenue Recognition

Revenue Recognition	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue Recognition	Revenue Recognition The following table provides the major sources of revenue by end-market sector for the years ended December 31, 2019 , 2018 and 2017 : Year Ended December 31, 2019 2018 2017 Mobile $479.3 $553.9 $528.6 Industrial 486.3 637.5 486.4 Energy 166.4 265.6 141.7 Other (1) 76.8 153.6 172.5 Total Net Sales $1,208.8 $1,610.6 $1,329.2 (1) “Other” for sales by end market sector includes the Company’s scrap and OCTG billet sales. The following table provides the major sources of revenue by product type for the years ended December 31, 2019 , 2018 and 2017 : Year Ended December 31, 2019 2018 2017 Bar $783.0 $1,030.7 $850.0 Tube 151.8 254.7 176.9 Value-add 240.6 284.3 265.3 Other (2) 33.4 40.9 37.0 Total Net Sales $1,208.8 $1,610.6 $1,329.2 (2) “Other” for sales by product type includes the Company’s scrap sales.

Restructuring Charges

Restructuring Charges	12 Months Ended
	Dec. 31, 2019
Restructuring and Related Activities [Abstract]
Restructuring Charges	Restructuring Charges During 2019, TimkenSteel made organizational changes to enhance profitable and sustainable growth. These company-wide actions included the restructuring of its business support functions, the reduction of management layers throughout the organization, the announced closure of the TimkenSteel Material Services (TMS) facility in Houston, Texas (See “ Note 6 - Disposition of Non-Core Assets ”), and other actions to further improve the Company’s overall cost structure. Through these restructuring efforts, the Company eliminated approximately 150 salaried positions and recognized restructuring charges of $8.6 million , consisting of severance and employee-related benefits. TimkenSteel recorded reserves for such restructuring charges as other current liabilities on the Consolidated Balance Sheets. The reserve balance at December 31, 2019 is expected to be substantially used in the next twelve months. The following is a summary of the restructuring reserve for the twelve months ended December 31, 2019 : Balance at December 31, 2018 $— Expenses (1) 8.6 Payments (2.6 ) Balance at December 31, 2019 $6.0 (1) Expenses of $8.6 million exclude stock compensation of $0.3 million that was accelerated as a result of the Company’s restructuring activities. There were no restructuring charges for the years ended December 31, 2018 and 2017.

Disposition of Non-Core Assets

Disposition of Non-Core Assets (Notes)	12 Months Ended
	Dec. 31, 2019
Discontinued Operations and Disposal Groups [Abstract]
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	Note 6 - Disposition of Non-Core Assets During the fourth quarter of 2019, management signed a letter of intent to dispose of the Company’s scrap processing facility in Akron, Ohio for cash consideration of approximately $4.0 million . This letter of intent and cash consideration were for the land, buildings, machinery and equipment associated with this facility. As a result of the agreement to sell the scrap processing facility, the Company ceased depreciation of the assets and recorded them as assets held for sale on the Consolidated Balance Sheet as of December 31, 2019. This disposal does not represent a discontinued operation. Additionally, the Company recorded an impairment charge of $7.3 million in the fourth quarter of 2019 which represents the cash consideration to be received less cost to sell the assets compared with the $11.3 million carrying value of the assets being sold, including supplies inventory. The sale of the assets was completed in the first quarter of 2020. Additionally, in the fourth quarter of 2019, the Board of Directors approved a plan to close the Company’s TMS facility in Houston, Texas in the first quarter of 2020. The closure of the facility does not qualify as a discontinued operation. At December 31, 2019, the associated assets did not meet the criteria to be classified as held for sale. As a result of the plan, the Company recorded the following charges in the fourth quarter of 2019: • Restructuring charges of approximately $0.7 million , primarily related to severance and other employee termination charges; • Inventory write-downs of $4.8 million , which represents the difference between the expected selling price and carrying value of the related inventory. The expected selling price was based upon the Company’s most recently published price lists related to this inventory; • Accelerated depreciation and amortization on TMS assets of $2.8 million in the fourth quarter of 2019, with an additional $1.6 million of accelerated depreciation to be recorded in the first quarter of 2020.

Other Income, Net

Other Income, Net	12 Months Ended
	Dec. 31, 2019
Other Income and Expenses [Abstract]
Other Income (Expense), Net	Other Income (Expense), net The following table provides the components of other income (expense), net for the years ended December 31, 2019 , 2018 and 2017 : Year Ended December 31, 2019 2018 2017 Pension and postretirement non-service benefit income $17.5 $25.2 $17.5 Loss from remeasurement of benefit plans (40.6 ) (43.5 ) (21.8 ) Foreign currency exchange gain (loss) — (0.2 ) 0.3 Miscellaneous income (expense) (0.2 ) (0.1 ) (0.1 ) Total other income (expense), net ($23.3 ) ($18.6 ) ($4.1 ) Non-service benefit income from all years is derived from the Company’s pension and other postretirement plans. The Company has had a favorable return on assets for its benefit plans, resulting in a benefit for all years. The loss from remeasurement of benefit plans is due to the Company performing mark-to-market accounting on its pension and postretirement assets at year-end and upon the occurrence of certain triggering events, partially offset with curtailments of $8.9 million due to the freezing of the salaried pension plan. For more details on the remeasurement and curtailments, refer to “ Note 15 - Retirement and Postretirement Plans .”

Income Tax Provision

Income Tax Provision	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Tax Provision	Income (loss) from operations before income taxes, based on geographic location of the operations to which such earnings are attributable, is provided below. Years Ended December 31, 2019 2018 ADJUSTED 2017 ADJUSTED United States ($130.8 ) ($10.1 ) ($37.0 ) Non-United States 4.7 1.9 7.2 Loss from operations before income taxes ($126.1 ) ($8.2 ) ($29.8 ) The provision (benefit) for income taxes consisted of the following: Years Ended December 31, 2019 2018 2017 Current: Federal $— $— $1.1 State and local 0.1 0.3 0.1 Foreign 0.4 0.7 0.6 Total current tax expense (benefit) $0.5 $1.0 $1.8 Deferred: Federal ($14.4 ) $0.4 ($0.4 ) State and local (2.0 ) — — Foreign (0.2 ) 0.4 0.1 Total deferred tax expense (benefit) (16.6 ) 0.8 (0.3 ) Provision (benefit) for incomes taxes ($16.1 ) $1.8 $1.5 For the year ended December 31, 2019 , TimkenSteel made $0.6 million in foreign tax payments, $0.2 million in state tax payments, and no U.S. federal payments, and had no refundable overpayments of state income taxes. For the year ended December 31, 2018 , TimkenSteel made $0.6 million in foreign tax payments, $0.2 million in state tax payments, and no U.S. federal payments, and had no refundable overpayments of state income taxes. The reconciliation between TimkenSteel’s effective tax rate on income (loss) from continuing operations and the statutory tax rate is as follows: Years Ended December 31, 2019 2018 2017 Tax at the U.S. federal statutory rate ($26.5 ) ($6.3 ) ($14.8 ) Adjustments: State and local income taxes, net of federal tax benefit (1.3 ) (0.5 ) (0.7 ) Foreign earnings taxed at different rates — 0.2 (0.2 ) U.S. research tax credit 0.2 (0.2 ) (0.2 ) Valuation allowance 10.2 7.5 6.3 Global intangible low-taxed income 0.2 0.5 — Tax reform impact - transition tax and rate change — — 10.2 Permanent differences 1.3 0.8 0.3 Other items, net (0.2 ) (0.2 ) 0.6 Provision (benefit) for income taxes ($16.1 ) $1.8 $1.5 Effective tax rate 12.8 % (5.9 )% (3.7 )% Income tax expense includes U.S. and international income taxes. Except as required under U.S. tax law, U.S. income and foreign withholding taxes have not been recognized on the excess of the amount for financial reporting over the tax basis of investments in foreign subsidiaries that is indefinitely reinvested outside the U.S. This amount becomes taxable upon a repatriation of assets from the subsidiary or a sale or liquidation of the subsidiary. Undistributed earnings of foreign subsidiaries outside of the U.S. were $6.5 million , $5.5 million and $2.9 million at December 31, 2019, 2018 and 2017, respectively. The 2017 cumulative earnings amounts were recognized through the transition tax calculation pursuant to the Tax and Jobs Act enacted on December 22, 2017. The Company has recognized a deferred tax liability in the amount of $0.7 million and $0.6 million at December 31, 2019 and 2018, respectively, for undistributed earnings at its TimkenSteel (Shanghai) Corporation Limited and TimkenSteel de Mexico S. de R.C. de C.V. subsidiaries, as those earnings are not permanently reinvested by the Company. The effect of temporary differences giving rise to deferred tax assets and liabilities at December 31, 2019 and 2018 was as follows: December 31, 2019 2018 Deferred tax liabilities: Depreciation ($98.6 ) ($101.4 ) Inventory (24.3 ) (9.9 ) Convertible debt (1.7 ) (2.6 ) Lease liability (3.4 ) — Other, net (0.7 ) (0.7 ) Deferred tax liabilities ($128.7 ) ($114.6 ) Deferred tax assets: Pension and postretirement benefits $47.9 $55.2 Other employee benefit accruals 7.2 7.1 Tax loss carryforwards 86.0 82.0 Intangible assets 1.1 1.1 Inventory 5.4 1.2 State decoupling 4.5 5.1 Leases - right-of-use asset 3.4 — Interest limitation 6.0 3.2 Other, net 1.2 2.6 Deferred tax assets subtotal $162.7 $157.5 Valuation allowances (34.9 ) (43.7 ) Deferred tax assets 127.8 113.8 Net deferred tax assets (liabilities) ($0.9 ) ($0.8 ) As of December 31, 2019 and 2018, the Company had a deferred tax liability of $0.9 million and $0.8 million , respectively, on the Consolidated Balance Sheets. As of December 31, 2019, TimkenSteel had loss carryforwards in the U.S. and various non-U.S. jurisdictions totaling $370.1 million (of which $314.9 relates to the U.S. and $55.2 million relates to the UK jurisdiction), having various expiration dates. TimkenSteel has provided valuation allowances of $34.9 million against these carryforwards. The majority of the non-U.S. loss carryforwards represent local country net operating losses for branches of TimkenSteel or entities treated as branches of TimkenSteel under U.S. tax law. Tax benefits have previously been recorded for these losses in the U.S. The related local country net operating loss carryforwards are offset fully by valuation allowances. As of December 31, 2019, TimkenSteel had a gross deferred tax asset for disallowed business interest in the U.S. of $25.2 million , which carries forward indefinitely. During the fourth quarter of 2019, TimkenSteel elected to change its method for valuing its inventories that previously used the LIFO method to the FIFO method. For tax purposes, prior to this change, the Company had a LIFO reserve of approximately $130 million. The LIFO reserve will be treated as taxable income over a four year period beginning in 2019. The Company expects this income to be fully offset by our net operating losses resulting in no cash tax liability. A deferred tax liability has been established for the future reversal amount and is included in the inventory line in the table above. During 2016, operating losses generated in the U.S. resulted in a decrease in the carrying value of the Company’s U.S. deferred tax liability to the point that would result in a net U.S. deferred tax asset at December 31, 2016. In light of TimkenSteel’s operating performance in the U.S. and current industry conditions, the Company assessed, based upon all available evidence, and concluded that it was more likely than not that it would not realize a portion of its U.S. deferred tax assets. The Company recorded a valuation allowance in 2016 and as a result of current year activity, the Company remained in a full valuation allowance position through 2019. Going forward, the need to maintain valuation allowances against deferred tax assets in the U.S. and other affected countries will cause variability in the Company’s effective tax rate. The Company will maintain a valuation allowance against its deferred tax assets in the U.S. and applicable foreign countries until sufficient positive evidence exists to eliminate them. TimkenSteel records interest and penalties related to uncertain tax positions as a component of provision (benefit) for income taxes. As of December 31, 2019, 2018 and 2017, TimkenSteel had no total gross unrecognized tax benefits, and no amounts which represented unrecognized tax benefits that would favorably impact TimkenSteel’s effective income tax rate in any future periods if such benefits were recognized. As of December 31, 2019, TimkenSteel does not anticipate a change in its unrecognized tax positions during the next 12 months. TimkenSteel had no accrued interest and penalties related to uncertain tax positions as of December 31, 2019, 2018 and 2017. TimkenSteel does not have any unrecognized tax benefits as of years ended December 31, 2019, 2018, and 2017. As of December 31, 2019, TimkenSteel is not subject to examination by the IRS. Pursuant to the Tax Sharing Agreement dated June 30, 2014 between TimkenSteel and The Timken Company, TimkenSteel may be subject to results from tax examinations for The Timken Company for federal, state and local and various foreign tax jurisdictions in various open audit periods. Tax Cuts and Jobs Act Bill On December 22, 2017, the Tax Cuts and Jobs Act (the Act) was signed into law, which resulted in significant changes to U.S. tax and related laws. Some of the provisions of the Act affecting corporations include, but are not limited to, a reduction in the federal corporate income tax rate from 35% to 21%, expensing the cost of acquired qualified property, the elimination of alternative minimum tax, a modification of the net operating loss deduction, and the creation of global intangible low-taxed income. Further, several changes and limitations to deductions were encompassed in the new law and were effective for TimkenSteel in 2018, including, interest expense, performance-based compensation, meals and entertainment expenses, transportation fringe benefits, and elimination of the domestic production activities deduction. We have evaluated the impact of the new tax law on TimkenSteel’s financial condition and results of operations. We did not experience a significant reduction in our effective income tax rate or our net deferred federal income tax assets as a result of the income tax rate reduction or changes to U.S. tax law.

Earnings (Loss) Per Share

Earnings (Loss) Per Share	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Earnings (Loss) Per Share	Note 9 - Earnings (Loss) Per Share Basic loss per share is computed based upon the weighted average number of common shares outstanding. Diluted loss per share is computed based upon the weighted average number of common shares outstanding plus the dilutive effect of common share equivalents calculated using the treasury stock method or if-converted method. For the Convertible Notes, the Company utilizes the if-converted method to calculate diluted loss per share. Under the if-converted method, the Company adjusts net earnings to add back interest expense (including amortization of debt discount) recognized on the Convertible Notes and includes the number of shares potentially issuable related to the Convertible Notes in the weighted average shares outstanding. Treasury stock is excluded from the denominator in calculating both basic and diluted loss per share. For the years ended December 31, 2019 , 2018 and 2017 , 3.7 million , 3.3 million , and 3.1 million shares issuable for equity-based awards, respectively, were excluded from the computation of diluted loss per share because the effect of their inclusion would have been anti-dilutive. In periods in which a net loss has occurred, as is the case for years ended December 31, 2019 , 2018 and 2017 , the dilutive effect of equity-based awards is not recognized and thus not utilized in the calculation of diluted loss per share, because the effect of their inclusion would have been anti-dilutive. The shares potentially issuable of 6.9 million related to the Convertible Notes were also anti-dilutive for the years ended December 31, 2019 , 2018 and 2017 . The following table sets forth the reconciliation of the numerator and the denominator of basic and diluted loss per share for the years ended December 31, 2019 , 2018 and 2017 : Year Ended December 31, 2019 2018 ADJUSTED 2017 ADJUSTED Numerator: Net income (loss) ($110.0 ) ($10.0 ) ($31.3 ) Denominator: Weighted average shares outstanding, basic 44.8 44.6 44.4 Weighted average shares outstanding, diluted 44.8 44.6 44.4 Basic earnings (loss) per share ($2.46 ) ($0.22 ) ($0.70 ) Diluted earnings (loss) per share ($2.46 ) ($0.22 ) ($0.70 )

Inventories

Inventories	12 Months Ended
	Dec. 31, 2019
Inventory Disclosure [Abstract]
Inventories	Inventories The components of inventories as of December 31, 2019 and 2018 were as follows: December 31, 2019 2018 ADJUSTED Manufacturing supplies $49.8 $46.9 Raw materials 26.0 35.2 Work in process 123.7 155.7 Finished products 93.1 142.8 Gross inventory 292.6 380.6 Allowance for inventory reserves (10.7 ) (6.1 ) Total inventories, net $281.9 $374.5 Previously, the Company utilized the LIFO method to account for a substantial portion of its inventory. As described in Note 1, in the fourth quarter of 2019 the Company elected to change the method of accounting for the inventory under the LIFO method to the FIFO method. The effects of this change in accounting principle have been retrospectively applied to all periods presented. The remaining inventories, including raw materials, manufacturing supplies inventory as well as international inventories, were not impacted by this change in accounting principle and continue to be valued by the average cost or FIFO methods. In connection with the announced closure of TMS, the company recorded an additional reserve against inventory of $4.8 million to state it at the lower of cost or net realizable value. See “Note 6 - Disposition of Non-Core Assets.”

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, Plant and Equipment The components of property, plant and equipment, net as of December 31, 2019 and 2018 were as follows: December 31, 2019 2018 Land $13.3 $14.1 Buildings and improvements 419.0 424.4 Machinery and equipment 1,404.6 1,404.2 Construction in progress 30.9 28.5 Subtotal 1,867.8 1,871.2 Less allowances for depreciation (1,241.4 ) (1,196.8 ) Property, plant and equipment, net $626.4 $674.4 Total depreciation expense was $67.4 million , $67.5 million , and $68.3 million for the years ended December 31, 2019 , 2018 , and 2017 respectively. Depreciation expense in 2019 includes $1.9 million of accelerated depreciation related to the announced closure of TMS. See “ Note 6 - Disposition of Non-Core Assets ” for additional information. For the year ended December 31, 2019, TimkenSteel recorded impairments and loss on disposal of assets of $9.0 million primarily related to the abandonment of certain equipment and the impairment of assets held for sale. For the years ended December 31, 2018 and 2017, TimkenSteel recorded approximately $0.5 million and $0.7 million , respectively, of impairment charges and loss on sale or disposal of assets related to the discontinued use of certain assets.

Intangible Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	Intangible Assets The components of intangible assets, net as of December 31, 2019 and 2018 were as follows: December 31, 2019 December 31, 2018 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Customer relationships $6.3 $5.0 $1.3 $6.3 $4.6 $1.7 Technology use 9.0 8.0 1.0 9.0 6.5 2.5 Capitalized software 61.1 49.1 12.0 61.6 48.0 13.6 Total intangible assets $76.4 $62.1 $14.3 $76.9 $59.1 $17.8 Intangible assets subject to amortization are amortized on a straight-line method over their legal or estimated useful lives. The weighted average useful lives of the customer relationships, technology use and capitalized software are 15 years , 15 years and 6 years , respectively. The weighted average useful life of total intangible assets is 8 years . Amortization expense for intangible assets for the years ended December 31, 2019 , 2018 , and 2017 was $6.1 million , $5.5 million and $6.6 million , respectively. Amortization expense in 2019 includes accelerated amortization of $0.9 million related to the announced closure of TMS. See “ Note 6 - Disposition of Non-Core Assets ” for additional information. During the year ended December 31, 2019, TimkenSteel recorded a loss on disposal of $0.1 million . For the year ended December 31, 2018 , TimkenSteel recorded approximately $0.4 million of impairment charges due to the discontinued use of certain capitalized software. No impairment charges were recorded for the year ended December 31, 2017. Based upon the intangible assets subject to amortization as of December 31, 2019 , TimkenSteel’s estimated annual amortization for the five succeeding years is shown below (in millions): Year Amortization Expense 2020 $3.3 2021 2.0 2022 1.8 2023 1.7 2024 0.8

Leases

Leases	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	Leases The Company has operating leases for office space, warehouses, land, machinery and equipment, vehicles and certain information technology equipment. These leases have remaining lease terms of less than one year to six years , some of which may include options to extend the leases for one or more years. Certain leases also include options to purchase the leased property. As of December 31, 2019 , the Company has no financing leases. The weighted average remaining lease term for our operating leases as of December 31, 2019 was 2.9 years Leases with an initial term of 12 months or less (short-term leases) are not recorded on the balance sheet; the Company recognizes lease expense for these leases on a straight-line basis over the lease term. For lease agreements entered into after the adoption of ASC 842, the Company combines lease and non-lease components. The Company’s lease agreements do not contain material residual value guarantees or material restrictive covenants. The Company recorded lease cost for the year ended December 31, 2019 as follows: Year Ended December 31, 2019 Operating lease cost $7.4 Short-term lease cost 1.9 Total lease cost $9.3 When available, the rate implicit in the lease is used to discount lease payments to present value; however, the Company’s leases generally do not provide a readily determinable implicit rate. Therefore, the incremental borrowing rate to discount the lease payments is estimated using market-based information available at lease commencement. The weighted average discount rate used to measure our operating lease liabilities as of December 31, 2019 was 4.5% . Supplemental cash flow information related to leases was as follows: Year Ended December 31, 2019 Cash paid for amounts included in the measurement of operating lease liabilities $7.5 Right-of-use assets obtained in exchange for operating lease obligations $4.3 Future minimum lease payments under non-cancellable leases as of December 31, 2019 were as follows: 2020 $6.8 2021 4.6 2022 2.2 2023 1.3 After 2023 0.5 Total future minimum lease payments 15.4 Less amount of lease payment representing interest (1.0 ) Total present value of lease payments $14.4 Future minimum lease payments under non-cancellable leases as of December 31, 2018 were as follows: 2019 $6.3 2020 5.2 2021 3.3 2022 1.0 2023 0.6 After 2023 — Total future minimum lease payments $16.4 As of December 31, 2019 , we have additional operating leases that have not yet commenced for which the present value of lease payments over the respective lease terms totals approximately $7.6 million . These leases are primarily manufacturing equipment to support the Company’s mobile value-added powertrain component product sales. These operating leases will commence in the first half of 2020 with lease terms of three to four years . Accordingly, these leases are not recorded on the Consolidated Balance Sheet at December 31, 2019.

Financing Arrangements

Financing Arrangements	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Financing Arrangements	Financing Arrangements Credit Agreement On January 26, 2018, the Company, as borrower, and certain domestic subsidiaries, as subsidiary guarantors, entered into the Second Amended and Restated Credit Agreement (Credit Agreement), with JP Morgan Chase Bank, N.A., as administrative agent, Bank of America, N.A., as syndication agent, and the other lenders party thereto, which amended and restated the Company’s credit agreement dated as of February 26, 2016. Amended Credit Agreement On October 15, 2019, the Company, as borrower, and certain domestic subsidiaries of the Company, as subsidiary guarantors, entered into a Third Amended and Restated Credit Agreement (the Amended Credit Agreement), with JP Morgan Chase Bank, N.A., as administrative agent (the Administrative Agent), Bank of America, N.A., as syndication agent, and the other lenders party thereto (collectively, the Lenders), which further amended and restated the Company’s existing Credit Agreement dated as of January 26, 2018. The Amended Credit Agreement provides for a $400.0 million asset-based revolving credit facility (the Credit Facility), including a $15.0 million sublimit for the issuance of commercial and standby letters of credit and a $40.0 million sublimit for swingline loans. Pursuant to the terms of the Amended Credit Agreement, the Company is entitled, on up to two occasions and subject to the satisfaction of certain conditions, to request increases in the commitments under the Amended Credit Agreement in the aggregate principal amount of up to $100.0 million , to the extent that existing or new lenders agree to provide such additional commitments. In addition to and independent of any increase described in the preceding sentence, the Company is entitled, subject to the satisfaction of certain conditions, to request a separate first-in, last-out (FILO) tranche in an aggregate principal amount of up to $30.0 million with a separate borrowing base and interest rate margins, in each case, to be agreed upon among the Company, the Administrative Agent and the Lenders providing the incremental FILO tranche. The availability of borrowings under the Credit Facility is subject to a borrowing base calculation based upon a valuation of the eligible accounts receivable, inventory and machinery and equipment of the Company and the subsidiary guarantors, each multiplied by an applicable advance rate. The availability of borrowings may be further modified by reserves established from time to time by the Administrative Agent in its permitted discretion. The interest rate per annum applicable to loans under the Credit Facility will be, at the Company’s option, equal to either (i) the alternate base rate plus the applicable margin or (ii) the relevant adjusted LIBO rate for an interest period of one, two, three or six months (as selected by the Company) plus the applicable margin. The base rate will be a fluctuating rate per annum equal to the greatest of (i) the prime rate as quoted in The Wall Street Journal, (ii) the effective Federal Reserve Bank of New York rate plus 0.50% and (iii) the adjusted LIBO rate for a one-month interest period on the applicable date, plus 1.00% . The adjusted LIBO rate will be equal to the applicable London interbank offered rate for the selected interest period, as adjusted for statutory reserve requirements for eurocurrency liabilities. The applicable margin will be determined by a pricing grid based on the Company’s average quarterly availability. In addition, the Company will pay a 0.25% per annum commitment fee on the average daily unused amount of the Credit Facility. The interest rate under the Amended Credit Agreement was 3.3% as of December 31, 2019. The amount available under the Amended Credit Agreement as of December 31, 2019 was $203.2 million . All of the indebtedness under the Credit Facility is guaranteed by the Company’s material domestic subsidiaries, as well as any other domestic subsidiary that the Company elects to make a party to the Amended Credit Agreement, and is secured by substantially all of the personal property of the Company and the subsidiary guarantors. The Credit Facility matures on October 15, 2024. Prior to the maturity date, amounts outstanding are required to be repaid (without reduction of the commitments thereunder) from mandatory prepayment events from the proceeds of certain asset sales, equity or debt issuances or casualty events. The Amended Credit Agreement contains certain customary covenants, including covenants that limit the ability of the Company and its subsidiaries to, among other things, (i) incur or suffer to exist certain liens, (ii) make investments, (iii) incur or guaranty additional indebtedness, (iv) enter into consolidations, mergers, acquisitions, sale-leaseback transactions and sales of assets, (v) make distributions and other restricted payments, (vi) change the nature of its business, (vii) engage in transactions with affiliates and (viii) enter into restrictive agreements, including agreements that restrict the ability to incur liens or make distributions. In addition, the Amended Credit Agreement requires the Company to (i) unless certain conditions are met, maintain certain minimum liquidity as specified in the Amended Credit Agreement during the period commencing on March 1, 2021 and ending on June 1, 2021 and (ii) maintain a minimum specified fixed charge coverage ratio on a springing basis if minimum availability requirements as specified in the Amended Credit Agreement are not maintained. The Amended Credit Agreement contains certain customary events of default. If any event of default occurs and is continuing, the Lenders would be entitled to take various actions, including the acceleration of amounts due under the Amended Credit Agreement, and exercise other rights and remedies. Convertible Notes In May 2016 , the Company issued $75.0 million aggregate principal amount of Convertible Senior Notes, and an additional $11.3 million principal amount to cover over-allotments (Convertible Notes). The Indenture for the Convertible Notes dated May 31, 2016, which was filed with the Securities and Exchange Commission as an exhibit to a Form 8-K filed on May 31, 2016, contains a complete description of the terms of the Convertible Notes. The key terms are as follows: Maturity Date: June 1, 2021 unless repurchased or converted earlier Interest Rate: 6.0% cash interest per year Interest Payments Dates: June 1 and December 1 of each year, beginning on December 1, 2016 Initial Conversion Price: Approximately $12.58 per common share of the Company Initial Conversion Rate: 79.5165 common shares per $1,000 principal amount of Notes The net proceeds to the Company from the offering were $83.2 million , after deducting the initial underwriters’ discount and fees and the offering expenses payable by the Company. The Company used the net proceeds to repay a portion of the amounts outstanding under its revolving credit agreement. The components of the Convertible Notes as of December 31, 2019 and December 31, 2018 were as follows: Year Ended December 31, 2019 2018 Principal $86.3 $86.3 Less: Debt issuance costs, net of amortization (0.7 ) (1.2 ) Less: Debt discount, net of amortization (7.0 ) (11.0 ) Convertible notes, net $78.6 $74.1 The initial value of the principal amount recorded as a liability at the date of issuance was $66.9 million , using an effective interest rate of 12.0% . The remaining $19.4 million of principal amount was allocated to the conversion feature and recorded as a component of shareholders’ equity at the date of issuance. This amount represents a discount to the debt to be amortized through interest expense using the effective interest method through the maturity of the Convertible Notes. Transaction costs were allocated to the liability and equity components based on their relative values. Transaction costs attributable to the liability component of $2.4 million are amortized to interest expense over the term of the Convertible Notes, and transaction costs attributable to the equity component of $0.7 million are included in shareholders’ equity. The following table sets forth total interest expense recognized related to the Convertible Notes: Year Ended December 31, 2019 2018 Contractual interest expense $5.2 $5.2 Amortization of debt issuance costs 0.4 0.4 Amortization of debt discount 4.0 3.6 Total $9.6 $9.2 Revenue Refunding Bonds On January 23, 2018, the Company redeemed in full $12.2 million of Ohio Water Development Revenue Refunding Bonds (originally due on November 1, 2025), $9.5 million of Ohio Air Quality Development Revenue Refunding Bonds (originally due on November 1, 2025) and $8.5 million of Ohio Pollution Control Revenue Refunding Bonds (originally due on June 1, 2033). Fair Value Measurement The fair value of the Convertible Notes was approximately $89.3 million as of December 31, 2019 . The fair value of the Convertible Notes, which falls within Level 1 of the fair value hierarchy as defined by Accounting Standards Codification (ASC) 820, Fair Value Measurements, is based on the last price traded in December 2019. TimkenSteel’s Credit Facility is variable-rate debt. As such, the carrying value is a reasonable estimate of fair value as interest rates on these borrowings approximate current market rates. This valuation falls within Level 2 of the fair value hierarchy and is based on quoted prices for similar assets and liabilities in active markets that are observable either directly or indirectly. Interest Paid The total cash interest paid for the year ended December 31, 2019 and 2018 was $11.5 million and $11.8 million , respectively.

Retirement and Postretirement B

Retirement and Postretirement Benefits	12 Months Ended
	Dec. 31, 2019
Defined Benefit Plan [Abstract]
Retirement and Postretirement Plans	Retirement and Postretirement Plans Eligible TimkenSteel employees, including certain employees in foreign countries, participate in the following TimkenSteel-sponsored plans: TimkenSteel Corporation Retirement Plan; TimkenSteel Corporation Bargaining Unit Pension Plan, Supplemental Pension Plan of TimkenSteel Corporation, TimkenSteel U.K. Pension Scheme, TimkenSteel Corporation Bargaining Unit Welfare Benefit Plan for Retirees, and TimkenSteel Corporation Welfare Benefit Plan for Retirees. During the second quarter of 2019, the Company amended the TimkenSteel Corporation Bargaining Unit Welfare Plan for Retirees relating to moving Medicare-eligible retirees to an individual plan on a Medicare healthcare exchange. The amendment reduced the postretirement liability by $70.2 million , and required the Company to perform a full remeasurement of its obligation and plan assets as of April 30, 2019. The $70.2 million reduction in the APBO was recognized in Other Comprehensive Income (Loss) and is being amortized as an offset to postretirement benefit cost over a period of 12 years (average remaining service period). In addition to the reduction of the APBO, the Company recognized a net remeasurement loss of $4.4 million . During the fourth quarter of 2019, the Company amended the Supplemental Pension Plan of TimkenSteel Corporation, which provides for the payment of nonqualified supplemental pension benefits to certain salaried participants in the TimkenSteel Corporation Retirement Plan. The amendment provides for the cessation of benefit accruals under the Supplemental Plan, effective as of December 31, 2020. Effective January 1, 2021, there will be no new accruals of benefits, including with respect to service accruals and the final average compensation determination. Certain of the Company’s named executive officers are participants in the plan. Existing benefits under the plan, as of December 31, 2020, will otherwise continue in accordance with the terms of the plan. This amendment reduced the pension liability, resulting in a curtailment gain of $0.8 million . This curtailment gain was recognized in Other Income (Expense) in the Consolidated Statement of Operations. During the fourth quarter of 2019, the Company amended the TimkenSteel Corporation Retirement Plan, which provides payments of tax-qualified pension benefits to certain salaried employees of the Company and its subsidiaries, to cease benefit accruals under the Pension Plan for all remaining active participants, effective as of December 31, 2020. This plan amendment reduced the pension liability, resulting in a curtailment gain of $8.1 million . This curtailment gain was recognized in Other Income (Expense) in the Consolidated Statement of Operations. During the fourth quarter of 2019, the Company also amended the TimkenSteel Corporation Welfare Benefit Plan for Retirees, under which certain retired salaried employees of the Company and its subsidiaries are eligible to receive a Company contribution for their medical and prescription drug benefits under the retiree welfare plan. The amendment was to eliminate the retiree medical subsidy, effective as of December 31, 2019, for all remaining active salaried participants who retire after December 31, 2019 (provided, however, that participants who are laid off on or before March 31, 2020 and who otherwise qualify for the retiree medical subsidy under the terms of the retiree welfare plan remain entitled to receive the retiree medical subsidy). This plan amendment reduced the pension liability by $2.3 million , was recognized in Other Comprehensive Income (Loss) and is being amortized as an offset to postretirement benefit cost in future periods. Pension benefits earned are generally based on years of service and compensation during active employment. TimkenSteel’s funding policy is consistent with the funding requirements of applicable laws and regulations. Asset allocations are established in a manner consistent with projected plan liabilities, benefit payments and expected rates of return for the various asset classes. The expected rate of return for the investment portfolio is based on expected rates of return for various asset classes, as well as historical asset class and fund performance. The following tables set forth the change in benefit obligation, change in plan assets, funded status and amounts recognized on the Consolidated Balance Sheets for the defined benefit pension plans as of December 31, 2019 and 2018 : Pension Postretirement Change in benefit obligation: 2019 2018 2019 2018 Benefit obligation at the beginning of year $1,178.3 $1,282.1 $194.7 $216.2 Service cost 17.4 17.2 1.1 1.6 Interest cost 48.9 45.6 5.9 7.6 Actuarial (gains) losses 145.7 (70.4 ) 11.4 (11.7 ) Benefits paid (72.3 ) (92.4 ) (14.4 ) (19.0 ) Plan amendment (0.7 ) 0.5 (72.5 ) — Curtailments (8.9 ) — — — Foreign currency translation adjustment 3.0 (4.3 ) — — Benefit obligation at the end of year $1,311.4 $1,178.3 $126.2 $194.7 Pension Postretirement Change in plan assets: 2019 2018 2019 2018 Fair value of plan assets at the beginning of year $1,054.4 $1,186.6 $86.1 $104.0 Actual return on plan assets 167.7 (45.5 ) 8.9 (1.3 ) Company contributions / payments 2.0 10.6 1.7 2.4 Benefits paid (72.3 ) (92.4 ) (14.4 ) (19.0 ) Foreign currency translation adjustment 3.6 (4.9 ) — — Fair value of plan assets at end of year $1,155.4 $1,054.4 $82.3 $86.1 Funded status at end of year ($156.0 ) ($123.9 ) ($43.9 ) ($108.6 ) The TimkenSteel Corporation Retirement Plan (Salaried Plan) has a provision that permits employees to elect to receive their pension benefits in a lump sum. In the fourth quarter 2018, the cumulative cost of all lump sums exceeded the sum of the service cost and interest cost components of net periodic pension cost for the Salaried Plan. For the year ended December 31, 2018 total settlements were $26.0 million . These settlements are included in benefits paid in the tables above and in the net remeasurement losses (gains) as a component of net periodic benefit cost. The cumulative cost of all lump sums did not exceed service cost and interest cost components of net periodic pension cost for the year ended December 31, 2019. For the years ended December 31, 2019 and 2018 , the pension plan had administrative expenses of $3.5 million and $2.2 million , respectively. These expenses are included in benefits paid in the tables above. The accumulated benefit obligation at December 31, 2019 exceeded the fair value of plan assets for two of the Company’s pension plans. For these plans, the benefit obligation was $998.5 million , the accumulated benefit obligation was $983.6 million and the fair value of plan assets was $817.3 million as of December 31, 2019 . The total pension accumulated benefit obligation for all plans was $1,294.5 million and $1,149.8 million as of December 31, 2019 and 2018 , respectively. Amounts recognized on the balance sheet at December 31, 2019 and 2018 , for TimkenSteel’s pension and postretirement benefit plans include: Pension Postretirement 2019 2018 2019 2018 Non-current assets $25.2 $10.5 $— $— Current liabilities (0.6 ) (0.6 ) (2.4 ) (2.4 ) Non-current liabilities (180.6 ) (133.8 ) (41.5 ) (106.2 ) Total ($156.0 ) ($123.9 ) ($43.9 ) ($108.6 ) Included in accumulated other comprehensive loss at December 31, 2019 and 2018 , were the following before-tax amounts that had not been recognized in net periodic benefit cost: Pension Postretirement 2019 2018 2019 2018 Unrecognized prior service (benefit) cost $0.5 $1.6 ($67.8 ) $0.9 Amounts expected to be amortized from accumulated other comprehensive loss (income) and included in total net periodic benefit cost during the year ended December 31, 2020 are as follows: Pension Postretirement Prior service (benefit) cost $0.3 ($6.0 ) The weighted average assumptions used in determining benefit obligation as of December 31, 2019 and 2018 were as follows: Pension Postretirement Assumptions: 2019 2018 2019 2018 Discount rate 3.42 % 4.30 % 3.42 % 4.34 % Future compensation assumption 2.32 % 2.36 % n/a n/a The weighted average assumptions used in determining benefit cost for the years ended December 31, 2019 and 2018 were as follows: Pension Postretirement Assumptions: 2019 2018 2019 2018 Discount rate (1) 4.30 % 3.68 % 4.34% /3.94% 3.66 % Future compensation assumption 2.36 % 2.37 % n/a n/a Expected long-term return on plan assets 6.41 % 6.45 % 5.00 % 5.00 % (1) The discount rate for the postretirement plans was adjusted after the second quarter 2019 amendment. To calculate benefit costs, the discount rate of 4.34% was used for January to April and the discount rate of 3.94% was used for May to December. The discount rate assumption is based on current rates of high-quality long-term corporate bonds over the same period that benefit payments will be required to be made. The expected rate of return on plan assets assumption is based on the weighted-average expected return on the various asset classes in the plans’ portfolios. The asset class return is developed using historical asset return performance as well as current market conditions such as inflation, interest rates and equity market performance. For measurement purposes, TimkenSteel assumed a weighted-average annual rate of increase in the per capita cost (health care cost trend rate) of 5.75% and 6.00% for 2019 and 2018 , respectively. A one percentage point increase in the assumed health care cost trend rate would have increased the 2019 and 2018 postretirement benefit obligation by $0.3 million and $1.1 million , respectively and increased the total service and interest cost components by $0.1 million in both the years ended December 31, 2019 and 2018 . A one percentage point decrease would have decreased the 2019 and 2018 postretirement benefit obligation by $0.2 million and $1.0 million , respectively and decreased the total service and interest cost components by $0.1 million in both the years ended December 31, 2019 and 2018. The components of net periodic benefit cost (income) for the years ended December 31, 2019 , 2018 and 2017 were as follows: Pension Postretirement Years Ended December 31, Years Ended December 31, Components of net periodic benefit cost (income): 2019 2018 2017 2019 2018 2017 Service cost $17.4 $17.2 $18.2 $1.1 $1.6 $1.6 Interest cost 48.9 45.6 49.1 5.9 7.6 $8.4 Expected return on plan assets (65.0 ) (74.0 ) (70.7 ) (3.9 ) (4.8 ) (5.2 ) Amortization of prior service cost 0.4 0.5 0.5 (3.8 ) 0.2 1.0 Curtailment (8.9 ) — — — — — Net remeasurement losses (gains) 43.1 49.1 12.5 6.4 (5.6 ) 9.3 Net Periodic Benefit Cost (Income) $35.9 $38.4 $9.6 $5.7 ($1.0 ) $15.1 TimkenSteel recognizes its overall responsibility to ensure that the assets of its various defined benefit pension plans are managed effectively and prudently and in compliance with its policy guidelines and all applicable laws. Preservation of capital is important; however, TimkenSteel also recognizes that appropriate levels of risk are necessary to allow its investment managers to achieve satisfactory long-term results consistent with the objectives and the fiduciary character of the pension funds. Asset allocations are established in a manner consistent with projected plan liabilities, benefit payments and expected rates of return for various asset classes. The expected rate of return for the investment portfolios is based on expected rates of return for various asset classes, as well as historical asset class and fund performance. The target allocations for plan assets are 21% equity securities, 61% debt securities and 18% in all other types of investments. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). The inputs used to measure fair value are classified into the following hierarchy: Level 1 - Unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 - Unadjusted quoted prices in active markets for similar assets or liabilities, or unadjusted quoted prices for identical or similar assets or liabilities in markets that are not active, or inputs other than quoted prices that are observable for the asset or liability. Level 3 - Unobservable inputs for the asset or liability. The following table presents the fair value hierarchy for those investments of TimkenSteel’s pension assets measured at fair value on a recurring basis as of December 31, 2019 : Total Level 1 Level 2 Level 3 Assets: Cash and cash equivalents $12.2 $0.9 $11.3 $— U.S government and agency securities 250.3 246.1 4.2 — Corporate bonds 102.7 — 102.7 — Equity securities 49.8 49.8 — — Mutual fund - fixed income 56.4 56.4 — — Total Assets in the fair value hierarchy $471.4 $353.2 $118.2 $— Assets measured at net asset value (1) 684.0 — — — Total Assets $1,155.4 $353.2 $118.2 $— (1) Certain assets that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. Such assets include common collective trusts that invest in equity securities and fixed income securities, limited partnerships, real estate partnerships, hedge funds, and risk parity investments. As of December 31, 2019 , these assets are redeemable at net asset value within 90 days. The following table presents the fair value hierarchy for those investments of TimkenSteel’s pension assets measured at fair value on a recurring basis as of December 31, 2018 : Total Level 1 Level 2 Level 3 Assets: Cash and cash equivalents $22.5 $0.6 $21.9 $— U.S government and agency securities 234.2 229.1 5.1 — Corporate bonds 97.4 — 97.4 — Equity securities 37.1 37.1 — — Mutual fund - fixed income 33.1 33.1 — — Mutual fund - real estate 7.7 7.7 — — Total Assets in the fair value hierarchy $432.0 $307.6 $124.4 $— Assets measured at net asset value (1) 622.4 — — — Total Assets $1,054.4 $307.6 $124.4 $— (1) Certain assets that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. Such assets include common collective trusts that invest in equity securities and fixed income securities, limited partnerships, real estate partnerships, and risk parity investments. As of December 31, 2018 , these assets were redeemable at net asset value within 90 days. The following table presents the fair value hierarchy for those investments of TimkenSteel’s postretirement assets measured at fair value on a recurring basis as of December 31, 2019 : Total Level 1 Level 2 Level 3 Assets: Cash and cash equivalents $3.0 $3.0 $— $— Mutual fund - fixed income 15.8 15.8 — — Total Assets in the fair value hierarchy $18.8 $18.8 $— $— Assets measured at net asset value (1) 63.5 — — — Total Assets $82.3 $18.8 $— $— (1) Certain assets that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. Such assets include common collective trusts that invest in equity securities and fixed income securities, limited partnerships, real estate partnerships, hedge funds, and risk parity investments. As of December 31, 2019 , these assets are redeemable at net asset value within 90 days. The following table presents the fair value hierarchy for those investments of TimkenSteel’s postretirement assets measured at fair value on a recurring basis as of December 31, 2018 : Total Level 1 Level 2 Level 3 Assets: Cash and cash equivalents $5.6 $5.6 $— $— Mutual fund - fixed income 8.9 8.9 — — Total Assets in the fair value hierarchy $14.5 $14.5 $— $— Assets measured at net asset value (1) 71.6 — — — Total Assets $86.1 $14.5 $— $— (1) Certain assets that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. Such assets include common collective trusts that invest in equity securities and fixed income securities, limited partnerships, real estate partnerships, and risk parity investments. As of December 31, 2018 , these assets were redeemable at net asset value within 90 days. Future benefit payments are expected to be as follows: Benefit Payments: Pension Postretirement 2020 $78.8 $11.9 2021 79.2 11.0 2022 85.6 10.3 2023 76.5 9.6 2024 76.0 9.0 2025-2029 374.3 39.3 The Company expects to make required contributions to its U.K. pension plan in 2020 of approximately $1.3 million . Defined Contribution Plans The Company recorded expense primarily related to employer matching and non-discretionary contributions to these defined contribution plans of $7.1 million in 2019 , $6.3 million in 2018 , and $5.4 million in 2017 .

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Stock-Based Compensation Description of the Plan On April 28, 2016, shareholders of TimkenSteel approved the TimkenSteel Corporation Amended and Restated 2014 Equity and Incentive Compensation Plan (TimkenSteel 2014 Plan), which authorizes the Compensation Committee of the TimkenSteel Board of Directors to grant non-qualified or incentive stock options, stock appreciation rights, stock awards (including restricted shares, restricted share unit awards, performance shares, performance units, deferred shares and common shares) and cash awards to TimkenSteel employees and non-employee directors. No more than 11.05 million TimkenSteel common shares may be delivered under the TimkenSteel 2014 Plan. The TimkenSteel 2014 Plan contains fungible share counting mechanics, which generally means that awards other than stock options and stock appreciation rights will be counted against the aggregate share limit as 2.50 common shares for every one common share that is actually issued or transferred under such awards. The TimkenSteel 2014 Plan authorized up to 3.0 million common shares for use in granting “replacement awards” to current holders of The Timken Company equity awards under The Timken Company’s equity compensation plans at the time of the spinoff. As of December 31, 2019, approximately 2.4 million shares of TimkenSteel common stock remained available for grants under the TimkenSteel 2014 Plan. In connection with the spinoff, stock compensation awards granted under The Timken Company Long-Term Incentive Plan (Timken LTIP Plan) and The Timken Company 2011 Long-Term Incentive Plan (Timken 2011 Plan) were adjusted as follows: • Vested and unvested stock options were adjusted so that the grantee holds options to purchase both The Timken Company and TimkenSteel common shares. • The adjustment to The Timken Company and TimkenSteel stock options, when combined, were intended to generally preserve the intrinsic value of each original option grant and the ratio of the exercise price to the fair market value of The Timken Company common shares on June 30, 2014. • Unvested restricted stock awards were replaced with adjusted, substitute awards for restricted shares or units, as applicable, of The Timken Company and TimkenSteel common shares. The new awards of restricted stock were intended to generally preserve the intrinsic value of the original award determined as of June 30, 2014. • Vesting periods of awards were unaffected by the adjustment and substitution. Awards granted in connection with the adjustment of awards originally issued under The Timken Company LTIP Plan and the Timken 2011 Plan are referred to as replacement awards under the TimkenSteel 2014 Plan and, as noted above, reduce the maximum number of TimkenSteel common shares available for delivery under the TimkenSteel 2014 Plan. TimkenSteel recorded compensation expense for both TimkenSteel and The Timken Company common shares for awards held by TimkenSteel employees only. The following table provides the significant assumptions used to calculate the grant date fair market values of options granted using a Black-Scholes option pricing method: 2019 2018 2017 Weighted-average fair value per option $5.54 $7.46 $7.68 Risk-free interest rate 2.63% 2.77% 2.21% Dividend yield —% —% —% Expected stock volatility 41.36% 41.67% 43.23% Expected life - years 6 6 6 The expected life of stock option awards granted is based on historical data and represents the period of time that options granted are expected to be held prior to exercise. Because of the absence of adequate stock price history of TimkenSteel common stock, expected volatility related to stock option awards granted subsequent to the spinoff is based on the historical volatility of a selected group of peer companies’ stock. Expected annual dividend yield is estimated using the most recent dividend payment per share as of the grant date, of which no dividends were paid in these grant periods. The risk-free rate for periods within the expected life of the option is based on the U.S. Treasury yield curve in effect at the time of the grant. The following summarizes TimkenSteel stock option activity from January 1, 2019 to December 31, 2019: Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (millions) Outstanding as of December 31, 2018 2,532,669 $21.33 Granted 329,720 $12.45 Exercised (25,039 ) $8.83 Canceled, forfeited or expired (195,780 ) $17.33 Outstanding as of December 31, 2019 2,641,570 $20.64 5.27 $0.2 Options expected to vest 403,774 $13.43 8.30 $— Options exercisable 2,237,796 $21.94 4.73 $0.2 Stock options presented in this table represent TimkenSteel awards only, including those held by The Timken Company employees. For stock options exercised during the period of January 1, 2019 to December 31, 2019, the total intrinsic value was $0.1 million with cash proceeds of $0.2 million . There was no tax benefit associated with these stock option exercises. The following summarizes TimkenSteel stock-settled restricted share award activity from January 1, 2019 to December 31, 2019: Number of Shares Weighted Average Grant Date Fair Value Outstanding as of December 31, 2018 817,884 $14.15 Granted 833,220 $9.86 Vested (365,800 ) $10.23 Canceled, forfeited or expired (111,635 ) $13.79 Outstanding as of December 31, 2019 1,173,669 $11.94 Restricted share awards presented in this table represent TimkenSteel awards only, including those held by The Timken Company employees. TimkenSteel recognized stock-based compensation expense of $7.4 million , $7.3 million and $6.5 million for the years ended December 31, 2019, 2018 and 2017, respectively, related to stock option awards and stock-settled restricted share awards. Outstanding restricted share awards include restricted stock units, performance-based restricted stock units and deferred shares that will settle in common shares. Outstanding restricted stock units generally cliff-vest after three years or vest in 25% increments annually beginning on the first anniversary of the date of grant. Performance-based restricted stock units vest based on achievement of specified performance objectives. As of December 31, 2019, unrecognized compensation cost related to stock option awards and stock-settled restricted stock units was $7.3 million , which is expected to be recognized over a weighted average period of 1.4 years . The calculations of unamortized expense and weighted-average periods include awards based on both TimkenSteel and The Timken Company stock awards held by TimkenSteel employees. Certain restricted stock units, including performance-based restricted stock units, are settled in cash and were adjusted and substituted as described above. TimkenSteel recognized a liability of $0.1 million and $0.8 million as of December 31, 2019 and 2018, respectively, for these awards which was included in salaries, wages and benefits, and other non-current liabilities on the Consolidated Balance Sheets. TimkenSteel paid $0.1 million for cash-settled restricted stock units during 2018. There were no cash-settled restricted stock units during 2019.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Changes in accumulated other comprehensive income (loss) for the years ended December 31, 2019 and 2018 by component were as follows: Foreign Currency Translation Adjustments Pension and Postretirement Liability Adjustments Total Balance as of December 31, 2018 ($7.3 ) ($1.6 ) ($8.9 ) Other comprehensive income before reclassifications, before income tax 0.5 — 0.5 Amounts reclassified from accumulated other comprehensive income (loss), before income tax — (2.4 ) (2.4 ) Amounts deferred to accumulated other comprehensive income (loss), before income tax — 72.2 72.2 Tax effect — (16.7 ) (16.7 ) Net current period other comprehensive income, net of income taxes 0.5 53.1 53.6 Balance as of December 31, 2019 ($6.8 ) $51.5 $44.7 Foreign Currency Translation Adjustments Pension and Postretirement Liability Adjustments Total Balance at December 31, 2017 ($5.9 ) ($1.7 ) ($7.6 ) Other comprehensive income before reclassifications, before income tax (1.4 ) (0.5 ) (1.9 ) Amounts reclassified from accumulated other comprehensive loss, before income tax — 0.7 0.7 Tax effect — (0.1 ) (0.1 ) Net current period other comprehensive income, net of income taxes (1.4 ) 0.1 (1.3 ) Balance as of December 31, 2018 ($7.3 ) ($1.6 ) ($8.9 ) The amount reclassified from accumulated other comprehensive income (loss) in the year ended December 31, 2019 for the pension and postretirement liability adjustment was included in other income, net in the Consolidated Statements of Operations. The amount deferred to accumulated other comprehensive income in the year ended December 31, 2019 , was a result of a plan amendment to the Company’s postretirement benefit plan. These accumulated other comprehensive income (loss) components are components of net periodic benefit cost. See “ Note 15 - Retirement and Postretirement Plans ” for additional information.

Contingencies

Contingencies	12 Months Ended
	Dec. 31, 2019
Loss Contingency Accrual, Disclosures [Abstract]
Contingencies	Contingencies TimkenSteel has a number of loss exposures incurred in the ordinary course of business, such as environmental claims, product warranty claims, and litigation. Establishing loss reserves for these matters requires management’s estimate and judgment regarding risk exposure and ultimate liability or realization. These loss reserves are reviewed periodically and adjustments are made to reflect the most recent facts and circumstances. Accruals related to environmental claims represent management’s best estimate of the fees and costs associated with these claims. Although it is not possible to predict with certainty the outcome of such claims, management believes that their ultimate dispositions should not have a material adverse effect on our financial position, cash flows or results of operations. As of both December 31, 2019 and 2018, TimkenSteel had a $1.5 million contingency reserve, related to loss exposures incurred in the ordinary course of business.

Relationships with The Timken C

Relationships with The Timken Company and Related Entities	12 Months Ended
	Dec. 31, 2019
Related Party Transactions [Abstract]
Relationships with The Timken Company and Related Entities	Relationships with The Timken Company and Related Entities Prior to the spinoff on June 30, 2014, TimkenSteel was managed and operated in the normal course of business with other affiliates of The Timken Company. Transactions between The Timken Company and TimkenSteel, with the exception of sale and purchase transactions and reimbursements for payments made to third-party service providers by The Timken Company on TimkenSteel’s behalf, are reflected in equity in the Consolidated Balance Sheets as net parent investment and in the Consolidated Statements of Cash Flows as a financing activity in net transfers (to)/from The Timken Company and affiliates. Transactions with The Timken Company TimkenSteel sold finished goods to The Timken Company. During the years ended December 31, 2019, 2018 and 2017, revenues from related-party sales of products totaled $26.1 million or 2.2% of net sales, $43.2 million , or 2.7% of net sales, and $48.5 million or 3.6% of net sales, respectively. TimkenSteel did not purchase material from The Timken Company during the years ending December 31, 2019, 2018 or 2017. In addition, certain of TimkenSteel’s third-party service providers were paid by The Timken Company on behalf of TimkenSteel. TimkenSteel would subsequently reimburse The Timken Company in cash for such payments. Material Agreements Between TimkenSteel and The Timken Company On June 30, 2014, TimkenSteel entered into a separation and distribution agreement and several other agreements with The Timken Company to effect the spinoff and to provide a framework for the relationship with The Timken Company. These agreements govern the relationship between TimkenSteel and The Timken Company subsequent to the completion of the spinoff and provide for the allocation between TimkenSteel and The Timken Company of assets, liabilities and obligations attributable to periods prior to the spinoff. Because these agreements were entered into in the context of a related party transaction, the terms may not be comparable to terms that would be obtained in a transaction between unaffiliated parties. Separation and Distribution Agreement — The separation and distribution agreement contains the key provisions relating to the spinoff, including provisions relating to the principal intercompany transactions required to effect the spinoff, the conditions to the spinoff and provisions governing the relationships between TimkenSteel and The Timken Company after the spinoff. Tax Sharing Agreement — The tax sharing agreement generally governs TimkenSteel’s and The Timken Company’s respective rights, responsibilities and obligations after the spinoff with respect to taxes for any tax period ending on or before the distribution date, as well as tax periods beginning before and ending after the distribution date. Generally, TimkenSteel is liable for all pre-distribution U.S. federal income taxes, foreign income taxes and non-income taxes attributable to TimkenSteel’s business, and all other taxes attributable to TimkenSteel, paid after the distribution. In addition, the tax sharing agreement addresses the allocation of liability for taxes that are incurred as a result of restructuring activities undertaken to effectuate the distribution. The tax sharing agreement also provides that TimkenSteel is liable for taxes incurred by The Timken Company that arise as a result of TimkenSteel’s taking or failing to take, as the case may be, certain actions that result in the distribution failing to meet the requirements of a tax-free distribution under Section 355 of the Internal Revenue Code of 1986, as amended. Employee Matters Agreement — TimkenSteel entered into an employee matters agreement with The Timken Company, which generally provides that TimkenSteel and The Timken Company each has responsibility for its own employees and compensation plans, subject to certain exceptions as described in the agreement. In general, prior to the spinoff, TimkenSteel employees participated in various retirement, health and welfare, and other employee benefit and compensation plans maintained by The Timken Company. Following the spinoff (or earlier, in the case of the tax-qualified defined benefit plans and retiree medical plans), pursuant to the employee matters agreement, TimkenSteel employees and former employees generally participate in similar plans and arrangements established and maintained by TimkenSteel. The employee matters agreement provides for the bifurcation of equity awards as described in Note 16 - Stock-Based Compensation . Among other things, the employee matters agreement also provides for TimkenSteel’s assumption of certain employment-related contracts that its employees originally entered into with The Timken Company, the allocation of certain employee liabilities and the cooperation between TimkenSteel and The Timken Company in the sharing of employee information.

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data (Unaudited)	The following selected quarterly operating results for each quarter of fiscal 2019 and 2018 have been adjusted to reflect the change in accounting principle as described in “ Note 1 - Basis of Presentation ”: Quarters ended December 31, 2019 September 30. 2019 As Reported Adjustments As Adjusted Net sales $226.9 $274.2 $— $274.2 Gross profit (18.0 ) 13.2 (15.8 ) (2.6 ) Net income (loss) (84.6 ) (4.6 ) (12.4 ) (17.0 ) Per share data: Basic earnings (loss) per share ($1.89 ) ($0.10 ) ($0.28 ) ($0.38 ) Diluted earnings (loss) per share ($1.89 ) ($0.10 ) ($0.28 ) ($0.38 ) Quarters ended June 30, 2019 March 31, 2019 As Reported Adjustments As Adjusted As Reported Adjustments As Adjusted Net sales $336.7 $— $336.7 $371.0 $— $371.0 Gross profit 25.4 (10.6 ) 14.8 29.1 (0.7 ) 28.4 Net income (loss) (4.4 ) (7.5 ) (11.9 ) 4.2 (0.7 ) 3.5 Per share data: Basic earnings (loss) per share ($0.10 ) ($0.17 ) ($0.27 ) $0.09 ($0.01 ) $0.08 Diluted earnings (loss) per share ($0.10 ) ($0.17 ) ($0.27 ) $0.09 ($0.01 ) $0.08 Quarters ended December 31, 2018 September 30, 2018 As Reported Adjustments As Adjusted As Reported Adjustments As Adjusted Net sales $406.4 $— $406.4 $409.9 $— $409.9 Gross profit 27.1 10.2 37.3 24.6 3.8 28.4 Net income (loss) (39.6 ) 10.2 (29.4 ) 1.4 3.8 5.2 Per share data: Basic earnings (loss) per share ($0.89 ) $0.23 ($0.66 ) $0.03 $0.09 $0.12 Diluted earnings (loss) per share ($0.89 ) $0.23 ($0.66 ) $0.03 $0.09 $0.12 Quarters ended June 30, 2018 March 31, 2018 As Reported Adjustments As Adjusted As Reported Adjustments As Adjusted Net sales $413.5 $— $413.5 $380.8 $— $380.8 Gross profit 32.1 6.4 38.5 21.1 1.3 22.4 Net income (loss) 8.4 6.4 14.8 (1.9 ) 1.3 (0.6 ) Per share data: Basic earnings (loss) per share $0.19 $0.14 $0.33 ($0.04 ) $0.03 ($0.01 ) Diluted earnings (loss) per share $0.19 $0.14 $0.33 ($0.04 ) $0.03 ($0.01 )

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Revenue Recognition	Revenue Recognition: TimkenSteel recognizes revenue from contracts at a point in time when it has satisfied its performance obligation and the customer obtains control of the goods, at the amount that reflects the consideration the Company expects to receive for those goods. The Company receives and acknowledges purchase orders from its customers, which define the quantity, pricing, payment and other applicable terms and conditions. In some cases, the Company receives a blanket purchase order from its customer, which includes pricing, payment and other terms and conditions, with quantities defined at the time the customer issues periodic releases from the blanket purchase order. Certain contracts contain variable consideration, which primarily consists of rebates that are accounted for in net sales and accrued based on the estimated probability of the requirements being met.
Cash Equivalents	Cash Equivalents: TimkenSteel considers all highly liquid investments with a maturity of three months or less when purchased to be cash equivalents.
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts: TimkenSteel maintains an allowance for doubtful accounts, which represents an estimate of losses expected from the accounts receivable portfolio, to reduce accounts receivable to their net realizable value. The allowance is based upon historical trends in collections and write-offs, management’s judgment of the probability of collecting accounts and management’s evaluation of business risk. TimkenSteel extends credit to customers satisfying pre-defined credit criteria. TimkenSteel believes it has limited concentration of credit risk due to the diversity of its customer base.
Inventories, Net	Inventories, Net: At December 31, 2019, inventories were stated at the lower of cost or net realizable value. During the fourth quarter of 2019, the Company elected to change its method for valuing its inventories that previously used the LIFO method to the FIFO method. The Company believes that the FIFO method is preferable as it improves comparability with our peers, more closely resembles the physical flow of our inventory, and aligns with how the Company internally manages the business. The remaining inventories, including raw materials, manufacturing supplies inventory as well as international (outside the U.S.) inventories, will continue to be valued using the FIFO or average cost method. The effects of the change in accounting principle from LIFO to FIFO have been retrospectively applied to all periods presented. Refer to “ Note 1 - Basis of Presentation ” for more information.
Property, Plant and Equipment, Net	Property, Plant and Equipment, Net: Property, plant and equipment, net are valued at cost less accumulated depreciation. Maintenance and repairs are charged to expense as incurred. The provision for depreciation is computed principally by the straight-line method based upon the estimated useful lives of the assets. The useful lives are approximately 30 years for buildings and three to 20 years for machinery and equipment.
Intangible Assets, Net	Intangible Assets, Net: Intangible assets subject to amortization are amortized on a straight-line method over their legal or estimated useful lives, with useful lives ranging from three to 15 years . In accordance with Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) Topic 350-40, “Internal-Use Software,” (ASC 350-40), TimkenSteel capitalizes certain costs incurred for computer software developed or obtained for internal use. TimkenSteel capitalizes substantially all external costs and qualifying internal costs related to the purchase and implementation of software projects used for business operations. Capitalized software costs primarily include purchased software and external consulting fees. Capitalized software projects are amortized over the estimated useful lives of the software.
Long-lived Assets	Long-lived Assets: Long-lived assets (including tangible assets and intangible assets subject to amortization) are reviewed for impairment when events or changes in circumstances have occurred indicating that the carrying value of the assets may not be recoverable. TimkenSteel tests recoverability of long-lived assets at the lowest level for which there are identifiable cash flows that are independent from the cash flows of other assets. Assets and asset groups held and used are measured for recoverability by comparing the carrying amount of the asset or asset group to the sum of future undiscounted net cash flows expected to be generated by the asset or asset group. Assumptions and estimates about future values and remaining useful lives of TimkenSteel’s long-lived assets are complex and subjective. They can be affected by a variety of factors, including external factors such as industry and economic trends and internal factors such as changes in TimkenSteel’s business strategy and internal forecasts. If an asset or asset group is considered to be impaired, the impairment loss that would be recognized is the amount by which the carrying amount of the assets exceeds the fair value of the assets. To determine fair value, TimkenSteel uses internal cash flow estimates discounted at an appropriate interest rate, third party appraisals, as appropriate, and/or market prices of similar assets, when available. Refer to “ Note 6 - Disposition of Non-Core Assets ” and “ Note 11 - Property, Plant and Equipment ” for additional information.
Product Warranties	Product Warranties: TimkenSteel accrues liabilities for warranties based upon specific claim incidents in accordance with accounting rules relating to contingent liabilities. Should TimkenSteel become aware of a specific potential warranty claim for which liability is probable and reasonably estimable, a specific charge is recorded and accounted for accordingly. TimkenSteel had no significant warranty claims for the years ended December 31, 2019 , 2018 or 2017 .
Income Taxes	Income Taxes: Deferred tax assets and liabilities are recorded for the future tax consequences attributable to differences between financial statement carrying amounts of existing assets and liabilities and their respective tax bases, as well as net operating loss and tax credit carryforwards. TimkenSteel accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. TimkenSteel recognizes deferred tax assets to the extent TimkenSteel believes these assets are more likely than not to be realized. In making such a determination, TimkenSteel considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If TimkenSteel determines that it would be able to realize deferred tax assets in the future in excess of their net recorded amount, TimkenSteel would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. TimkenSteel records uncertain tax positions in accordance with FASB ASC Topic 740, “Income Taxes” (ASC 740), on the basis of a two-step process whereby (1) TimkenSteel determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position, and (2) for those tax positions that meet the more-likely-than-not recognition threshold, TimkenSteel recognizes the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority. TimkenSteel recognizes interest and penalties related to unrecognized tax benefits within the provision (benefit) for income taxes line in the accompanying Consolidated Statements of Operations. Accrued interest and penalties are included within the related tax liability line in the Consolidated Balance Sheets. During the year ended December 31, 2018, the Company made the accounting policy election to treat taxes related to Global Intangible Low-Taxed Income (GILTI) as a current period expense when incurred.
Foreign Currency Translation	Foreign Currency: Assets and liabilities of subsidiaries are translated at the rate of exchange in effect on the balance sheet date. Income and expenses are translated at the average rates of exchange prevailing during the year. The related translation adjustments are reflected as a separate component of accumulated other comprehensive loss. Gains and losses resulting from foreign currency transactions are included in other expense, net in the Consolidated Statements of Operations. TimkenSteel realized a foreign currency exchange loss of $0.2 million in 2018 and a gain of $0.3 million in 2017 . There were no foreign currency exchange gains or losses in 2019.
Pension and Other Postretirement Plans, Policy [Policy Text Block]	Pension and Other Postretirement Benefits: TimkenSteel recognizes an overfunded status or underfunded status (e.g., the difference between the fair value of plan assets and the benefit obligations) as either an asset or a liability for its defined benefit pension and other postretirement benefit plans on the Consolidated Balance Sheets. The Company recognizes actuarial gains and losses immediately through net periodic benefit cost in the Consolidated Statements of Operations upon the annual remeasurement at December 31, or on an interim basis as triggering events warrant remeasurement. In addition, the Company uses fair value to account for the value of plan assets.
Stock-Based Compensation	Stock-Based Compensation: TimkenSteel recognizes stock-based compensation expense based on the grant date fair value of the stock-based awards over their required vesting period on a straight-line basis, whether the awards were granted with graded or cliff vesting. Stock options are issued with an exercise price equal to the closing market price of TimkenSteel common shares on the date of grant. The fair value of stock options is determined using a Black-Scholes option pricing model, which incorporates assumptions regarding the expected volatility, the expected option life, the risk-free interest rate and the expected dividend yield. The fair value of stock-based awards that will settle in TimkenSteel common shares, other than stock options, is based on the closing market price of TimkenSteel common shares on the grant date. The fair values of stock-based awards that will settle in cash are remeasured at each reporting period until settlement of the awards. TimkenSteel recognizes all excess tax benefits and tax deficiencies as income tax expense or benefit in the Consolidated Statements of Operations. The excess tax benefits and tax deficiencies are considered discrete items in the reporting period they occur and are not included in the estimate of an entity’s annual effective tax rate.
Research and Development	Research and Development: Expenditures for TimkenSteel research and development amounted to $4.1 million for the year ended December 31, 2019, $8.1 million for the year ended December 31, 2018 and $ 8.0 million for the years ended December 31, 2017, and were recorded as a component of selling, general and administrative expenses in the Consolidated Statements of Operations. These expenditures may fluctuate from year to year depending on special projects and the needs of TimkenSteel and its customers.
Adoption of New Accounting Standards	Adoption of New Accounting Standards: The Company adopted the following Accounting Standard Updates (ASU) in the first quarter of 2019, all of which were effective as of January 1, 2019. The adoption of these standards had no impact on the Consolidated Financial Statements or the related Notes to the Consolidated Financial Statements. Standards Adopted Description ASU 2018-07, Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting The standard provides an expanded scope of Topic 718, to include share-based payment transactions for acquiring goods and services from nonemployees. ASU 2018-02, Reporting Comprehensive Income: Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income The standard permits entities to reclassify tax effects stranded in accumulated other comprehensive income as a result of tax reform to retained earnings. ASU 2017-11, Distinguishing Liabilities from Equity; Derivatives and Hedging The standard eliminates the requirement to consider “down round” features when determining whether certain equity-linked financial instruments or embedded features are indexed to an entity’s own stock. On January 1, 2019, the Company adopted ASU 2016-02, “Leases (Topics 842),” which requires lessees to recognize lease liabilities and right-of-use assets on the balance sheet for not only finance (previously capital) leases but also operating leases. The standard also requires additional quantitative and qualitative disclosures. The Company adopted the standard using the modified retrospective transition approach without adjusting comparative periods. The Company elected certain of the practical expedients permitted under the transition guidance within the new standard as follows: • A package of practical expedients to not reassess: ◦ Whether a contract is or contains a lease ◦ Lease classification ◦ Initial direct costs • A practical expedient to not reassess certain land easements The Company has implemented internal controls and lease accounting software to enable the quantification of the expected impact on the Consolidated Balance Sheets and to facilitate the calculations of the related accounting entries and disclosures. Adoption of the lease standard resulted in recognition of right-to-use assets and lease liabilities of $16.0 million as of January 1, 2019. Adoption of the lease standard had no impact on the Company’s debt covenant compliance under its current agreements. Also, the standard did not materially affect the Company’s results of operations or its cash flows. Refer to “ Note 13 - Leases ” for additional information. Accounting Standards Issued But Not Yet Adopted The Company has considered the recent ASUs issued by the Financial Accounting Standards Board summarized below: Standard Pending Adoption Description Effective Date Anticipated Impact ASU 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40) The standard aligns the requirements for capitalizing implementation costs in cloud computing software arrangements with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. January 1, 2020 The Company evaluated the impact of the adoption of this ASU on its results of operations and financial condition and determined that the impact is immaterial. ASU 2018-14, Compensation - Retirement Benefits - Defined Benefit Plans - General (Subtopic 715-20) The standard eliminates, modifies and adds disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. January 1, 2021 The Company is currently evaluating the impact of the adoption of this ASU on its results of operations and financial condition. ASU 2018-13, Fair Value Measurement (Topic 820) The standard eliminates, modifies and adds disclosure requirements for fair value measurements. January 1, 2020 The Company evaluated the impact of the adoption of this ASU on its results of operations and financial condition and determined that the impact is immaterial. ASU 2016-13, Measurement of Credit Losses on Financial Instruments The standard changes how entities will measure credit losses for most financial assets, including trade and other receivables and replaces the current incurred loss approach with an expected loss model. January 1, 2020 The Company evaluated the impact of the adoption of this ASU on its results of operations and financial condition and determined that the impact is immaterial. ASU 2019-12, Income Taxes (Topic 740) The standard simplifies the accounting for income taxes by removing various exceptions. January 1, 2021 The Company is currently evaluating the impact of the adoption of this ASU on its results of operations and financial condition.

Basis of Presentation Basis of

Basis of Presentation Basis of Presentation (Tables)	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Accounting Changes	The following table reflects the effect of the change in the accounting principle on the 2019 Consolidated Financial Statements (dollars in million, except per share data): For the Year Ended December 31, 2019 As Computed under LIFO As Reported under FIFO Effect of Change Statement of Operations Cost of products sold $1,160.5 $1,186.2 $25.7 Gross profit 48.3 22.6 (25.7 ) Income (loss) before income taxes (100.4 ) (126.1 ) (25.7 ) Net income (loss) (84.3 ) (110.0 ) (25.7 ) Per Share Data: Basic earnings (loss) per share (1.89 ) (2.46 ) (0.57 ) Diluted earnings (loss) per share (1.89 ) (2.46 ) (0.57 ) For the Year Ended December 31, 2019 As Computed under LIFO As Reported under FIFO Effect of Change Statement of Comprehensive Income (Loss) Net (loss) income ($84.3 ) ($110.0 ) ($25.7 ) Comprehensive income (loss), net of tax (30.7 ) (56.4 ) (25.7 ) As of December 31, 2019 As Computed under LIFO As Reported under FIFO Effect of Change Balance Sheet Inventories, net $229.8 $281.9 $52.1 Retained deficit (249.4 ) (301.5 ) (52.1 ) For the Year Ended December 31, 2019 As Computed under LIFO As Reported under FIFO Effect of Change Statement of Cash Flows Net (loss) income ($84.3 ) ($110.0 ) ($25.7 ) Changes in operating assets and liabilities: Inventories, net 66.9 92.6 25.7 The following tables reflect the impact to the financial statement line items as a result of the change in accounting principle for the prior periods presented in the accompanying financial statements (dollars in millions, except per share data): Consolidated Statement of Operations 2018 2017 As Reported Adjustments As Adjusted As Reported Adjustments As Adjusted Cost of products sold $ 1,505.7 $ (21.7 ) $ 1,484.0 $ 1,261.4 $ (12.5 ) $ 1,248.9 Gross profit 104.9 21.7 126.6 67.8 12.5 80.3 Income (loss) before income taxes (29.9 ) 21.7 (8.2 ) (42.3 ) 12.5 (29.8 ) Net income (loss) (31.7 ) 21.7 (10.0 ) (43.8 ) 12.5 (31.3 ) Per Share Data: Basic earnings (loss) per share $ (0.71 ) $ 0.49 $ (0.22 ) $ (0.99 ) $ 0.29 $ (0.70 ) Diluted earnings (loss) per share $ (0.71 ) $ 0.49 $ (0.22 ) $ (0.99 ) $ 0.29 $ (0.70 ) Consolidated Statement of Comprehensive Income (Loss) 2018 2017 As Reported Adjustments As Adjusted As Reported Adjustments As Adjusted Net income (loss) $ (31.7 ) $ 21.7 $ (10.0 ) $ (43.8 ) $ 12.5 $ (31.3 ) Comprehensive income (loss), net of tax (33.0 ) 21.7 (11.3 ) (42.0 ) 12.5 (29.5 ) Consolidated Balance Sheet 2018 As Reported Adjustments As Adjusted Inventories, net $ 296.8 $ 77.7 $ 374.5 Retained deficit (1) (269.2 ) 77.7 (191.5 ) (1) As a result of the accounting change, retained deficit as of January 1, 2017 decreased from $193.9 million , as originally reported using the LIFO method, to $150.4 million using the FIFO method. The change of $43.5 million is reflected as a cumulative change in accounting principle in the Consolidated Statements of Shareholders’ Equity. Consolidated Statement of Cash Flows 2018 2017 As Reported Adjustments As Adjusted As Reported Adjustments As Adjusted Net income (loss) $ (31.7 ) $ 21.7 $ (10.0 ) $ (43.8 ) $ 12.5 $ (31.3 ) Changes in operating assets and liabilities: Inventories, net (72.8 ) (21.7 ) (94.5 ) (59.8 ) (12.5 ) (72.3 ) The Company has considered the recent ASUs issued by the Financial Accounting Standards Board summarized below: Standard Pending Adoption Description Effective Date Anticipated Impact ASU 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40) The standard aligns the requirements for capitalizing implementation costs in cloud computing software arrangements with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. January 1, 2020 The Company evaluated the impact of the adoption of this ASU on its results of operations and financial condition and determined that the impact is immaterial. ASU 2018-14, Compensation - Retirement Benefits - Defined Benefit Plans - General (Subtopic 715-20) The standard eliminates, modifies and adds disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. January 1, 2021 The Company is currently evaluating the impact of the adoption of this ASU on its results of operations and financial condition. ASU 2018-13, Fair Value Measurement (Topic 820) The standard eliminates, modifies and adds disclosure requirements for fair value measurements. January 1, 2020 The Company evaluated the impact of the adoption of this ASU on its results of operations and financial condition and determined that the impact is immaterial. ASU 2016-13, Measurement of Credit Losses on Financial Instruments The standard changes how entities will measure credit losses for most financial assets, including trade and other receivables and replaces the current incurred loss approach with an expected loss model. January 1, 2020 The Company evaluated the impact of the adoption of this ASU on its results of operations and financial condition and determined that the impact is immaterial. ASU 2019-12, Income Taxes (Topic 740) The standard simplifies the accounting for income taxes by removing various exceptions. January 1, 2021 The Company is currently evaluating the impact of the adoption of this ASU on its results of operations and financial condition. The Company adopted the following Accounting Standard Updates (ASU) in the first quarter of 2019, all of which were effective as of January 1, 2019. The adoption of these standards had no impact on the Consolidated Financial Statements or the related Notes to the Consolidated Financial Statements. Standards Adopted Description ASU 2018-07, Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting The standard provides an expanded scope of Topic 718, to include share-based payment transactions for acquiring goods and services from nonemployees. ASU 2018-02, Reporting Comprehensive Income: Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income The standard permits entities to reclassify tax effects stranded in accumulated other comprehensive income as a result of tax reform to retained earnings. ASU 2017-11, Distinguishing Liabilities from Equity; Derivatives and Hedging The standard eliminates the requirement to consider “down round” features when determining whether certain equity-linked financial instruments or embedded features are indexed to an entity’s own stock.

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Schedule of Accounting Changes	The following table reflects the effect of the change in the accounting principle on the 2019 Consolidated Financial Statements (dollars in million, except per share data): For the Year Ended December 31, 2019 As Computed under LIFO As Reported under FIFO Effect of Change Statement of Operations Cost of products sold $1,160.5 $1,186.2 $25.7 Gross profit 48.3 22.6 (25.7 ) Income (loss) before income taxes (100.4 ) (126.1 ) (25.7 ) Net income (loss) (84.3 ) (110.0 ) (25.7 ) Per Share Data: Basic earnings (loss) per share (1.89 ) (2.46 ) (0.57 ) Diluted earnings (loss) per share (1.89 ) (2.46 ) (0.57 ) For the Year Ended December 31, 2019 As Computed under LIFO As Reported under FIFO Effect of Change Statement of Comprehensive Income (Loss) Net (loss) income ($84.3 ) ($110.0 ) ($25.7 ) Comprehensive income (loss), net of tax (30.7 ) (56.4 ) (25.7 ) As of December 31, 2019 As Computed under LIFO As Reported under FIFO Effect of Change Balance Sheet Inventories, net $229.8 $281.9 $52.1 Retained deficit (249.4 ) (301.5 ) (52.1 ) For the Year Ended December 31, 2019 As Computed under LIFO As Reported under FIFO Effect of Change Statement of Cash Flows Net (loss) income ($84.3 ) ($110.0 ) ($25.7 ) Changes in operating assets and liabilities: Inventories, net 66.9 92.6 25.7 The following tables reflect the impact to the financial statement line items as a result of the change in accounting principle for the prior periods presented in the accompanying financial statements (dollars in millions, except per share data): Consolidated Statement of Operations 2018 2017 As Reported Adjustments As Adjusted As Reported Adjustments As Adjusted Cost of products sold $ 1,505.7 $ (21.7 ) $ 1,484.0 $ 1,261.4 $ (12.5 ) $ 1,248.9 Gross profit 104.9 21.7 126.6 67.8 12.5 80.3 Income (loss) before income taxes (29.9 ) 21.7 (8.2 ) (42.3 ) 12.5 (29.8 ) Net income (loss) (31.7 ) 21.7 (10.0 ) (43.8 ) 12.5 (31.3 ) Per Share Data: Basic earnings (loss) per share $ (0.71 ) $ 0.49 $ (0.22 ) $ (0.99 ) $ 0.29 $ (0.70 ) Diluted earnings (loss) per share $ (0.71 ) $ 0.49 $ (0.22 ) $ (0.99 ) $ 0.29 $ (0.70 ) Consolidated Statement of Comprehensive Income (Loss) 2018 2017 As Reported Adjustments As Adjusted As Reported Adjustments As Adjusted Net income (loss) $ (31.7 ) $ 21.7 $ (10.0 ) $ (43.8 ) $ 12.5 $ (31.3 ) Comprehensive income (loss), net of tax (33.0 ) 21.7 (11.3 ) (42.0 ) 12.5 (29.5 ) Consolidated Balance Sheet 2018 As Reported Adjustments As Adjusted Inventories, net $ 296.8 $ 77.7 $ 374.5 Retained deficit (1) (269.2 ) 77.7 (191.5 ) (1) As a result of the accounting change, retained deficit as of January 1, 2017 decreased from $193.9 million , as originally reported using the LIFO method, to $150.4 million using the FIFO method. The change of $43.5 million is reflected as a cumulative change in accounting principle in the Consolidated Statements of Shareholders’ Equity. Consolidated Statement of Cash Flows 2018 2017 As Reported Adjustments As Adjusted As Reported Adjustments As Adjusted Net income (loss) $ (31.7 ) $ 21.7 $ (10.0 ) $ (43.8 ) $ 12.5 $ (31.3 ) Changes in operating assets and liabilities: Inventories, net (72.8 ) (21.7 ) (94.5 ) (59.8 ) (12.5 ) (72.3 ) The Company has considered the recent ASUs issued by the Financial Accounting Standards Board summarized below: Standard Pending Adoption Description Effective Date Anticipated Impact ASU 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40) The standard aligns the requirements for capitalizing implementation costs in cloud computing software arrangements with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. January 1, 2020 The Company evaluated the impact of the adoption of this ASU on its results of operations and financial condition and determined that the impact is immaterial. ASU 2018-14, Compensation - Retirement Benefits - Defined Benefit Plans - General (Subtopic 715-20) The standard eliminates, modifies and adds disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. January 1, 2021 The Company is currently evaluating the impact of the adoption of this ASU on its results of operations and financial condition. ASU 2018-13, Fair Value Measurement (Topic 820) The standard eliminates, modifies and adds disclosure requirements for fair value measurements. January 1, 2020 The Company evaluated the impact of the adoption of this ASU on its results of operations and financial condition and determined that the impact is immaterial. ASU 2016-13, Measurement of Credit Losses on Financial Instruments The standard changes how entities will measure credit losses for most financial assets, including trade and other receivables and replaces the current incurred loss approach with an expected loss model. January 1, 2020 The Company evaluated the impact of the adoption of this ASU on its results of operations and financial condition and determined that the impact is immaterial. ASU 2019-12, Income Taxes (Topic 740) The standard simplifies the accounting for income taxes by removing various exceptions. January 1, 2021 The Company is currently evaluating the impact of the adoption of this ASU on its results of operations and financial condition. The Company adopted the following Accounting Standard Updates (ASU) in the first quarter of 2019, all of which were effective as of January 1, 2019. The adoption of these standards had no impact on the Consolidated Financial Statements or the related Notes to the Consolidated Financial Statements. Standards Adopted Description ASU 2018-07, Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting The standard provides an expanded scope of Topic 718, to include share-based payment transactions for acquiring goods and services from nonemployees. ASU 2018-02, Reporting Comprehensive Income: Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income The standard permits entities to reclassify tax effects stranded in accumulated other comprehensive income as a result of tax reform to retained earnings. ASU 2017-11, Distinguishing Liabilities from Equity; Derivatives and Hedging The standard eliminates the requirement to consider “down round” features when determining whether certain equity-linked financial instruments or embedded features are indexed to an entity’s own stock.

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Revenue from External Customers by Geographic Areas	Year Ended December 31, 2019 2018 2017 Net Sales: United States $1,096.8 $1,456.2 $1,207.7 Foreign 112.0 154.4 121.5 $1,208.8 $1,610.6 $1,329.2
Long-lived Assets by Geographic Areas	December 31, 2019 2018 Long-lived Assets, net: United States $654.8 $692.0 Foreign 0.2 0.2 $655.0 $692.2

Revenue Recognition (Tables)

Revenue Recognition (Tables)	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following table provides the major sources of revenue by end-market sector for the years ended December 31, 2019 , 2018 and 2017 : Year Ended December 31, 2019 2018 2017 Mobile $479.3 $553.9 $528.6 Industrial 486.3 637.5 486.4 Energy 166.4 265.6 141.7 Other (1) 76.8 153.6 172.5 Total Net Sales $1,208.8 $1,610.6 $1,329.2 (1) “Other” for sales by end market sector includes the Company’s scrap and OCTG billet sales. The following table provides the major sources of revenue by product type for the years ended December 31, 2019 , 2018 and 2017 : Year Ended December 31, 2019 2018 2017 Bar $783.0 $1,030.7 $850.0 Tube 151.8 254.7 176.9 Value-add 240.6 284.3 265.3 Other (2) 33.4 40.9 37.0 Total Net Sales $1,208.8 $1,610.6 $1,329.2 (2)

Restructuring Charges (Tables)

Restructuring Charges (Tables)	12 Months Ended
	Dec. 31, 2019
Restructuring and Related Activities [Abstract]
Schedule of Restructuring Reserve	The following is a summary of the restructuring reserve for the twelve months ended December 31, 2019 : Balance at December 31, 2018 $— Expenses (1) 8.6 Payments (2.6 ) Balance at December 31, 2019 $6.0 (1) Expenses of $8.6 million exclude stock compensation of $0.3 million that was accelerated as a result of the Company’s restructuring activities.

Other Income, Net (Tables)

Other Income, Net (Tables)	12 Months Ended
	Dec. 31, 2019
Other Income and Expenses [Abstract]
Schedule of Other Income (Expense), net	The following table provides the components of other income (expense), net for the years ended December 31, 2019 , 2018 and 2017 : Year Ended December 31, 2019 2018 2017 Pension and postretirement non-service benefit income $17.5 $25.2 $17.5 Loss from remeasurement of benefit plans (40.6 ) (43.5 ) (21.8 ) Foreign currency exchange gain (loss) — (0.2 ) 0.3 Miscellaneous income (expense) (0.2 ) (0.1 ) (0.1 ) Total other income (expense), net ($23.3 ) ($18.6 ) ($4.1 )

Income Tax Provision (Tables)

Income Tax Provision (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax, Domestic and Foreign	Income (loss) from operations before income taxes, based on geographic location of the operations to which such earnings are attributable, is provided below. Years Ended December 31, 2019 2018 ADJUSTED 2017 ADJUSTED United States ($130.8 ) ($10.1 ) ($37.0 ) Non-United States 4.7 1.9 7.2 Loss from operations before income taxes ($126.1 ) ($8.2 ) ($29.8 )
Schedule of (Benefit) Provision for Income Taxes	The provision (benefit) for income taxes consisted of the following: Years Ended December 31, 2019 2018 2017 Current: Federal $— $— $1.1 State and local 0.1 0.3 0.1 Foreign 0.4 0.7 0.6 Total current tax expense (benefit) $0.5 $1.0 $1.8 Deferred: Federal ($14.4 ) $0.4 ($0.4 ) State and local (2.0 ) — — Foreign (0.2 ) 0.4 0.1 Total deferred tax expense (benefit) (16.6 ) 0.8 (0.3 ) Provision (benefit) for incomes taxes ($16.1 ) $1.8 $1.5
Schedule of Effective Income Tax Rate Reconciliation	The reconciliation between TimkenSteel’s effective tax rate on income (loss) from continuing operations and the statutory tax rate is as follows: Years Ended December 31, 2019 2018 2017 Tax at the U.S. federal statutory rate ($26.5 ) ($6.3 ) ($14.8 ) Adjustments: State and local income taxes, net of federal tax benefit (1.3 ) (0.5 ) (0.7 ) Foreign earnings taxed at different rates — 0.2 (0.2 ) U.S. research tax credit 0.2 (0.2 ) (0.2 ) Valuation allowance 10.2 7.5 6.3 Global intangible low-taxed income 0.2 0.5 — Tax reform impact - transition tax and rate change — — 10.2 Permanent differences 1.3 0.8 0.3 Other items, net (0.2 ) (0.2 ) 0.6 Provision (benefit) for income taxes ($16.1 ) $1.8 $1.5 Effective tax rate 12.8 % (5.9 )% (3.7 )%
Schedule of Deferred Tax Assets and Liabilities	The effect of temporary differences giving rise to deferred tax assets and liabilities at December 31, 2019 and 2018 was as follows: December 31, 2019 2018 Deferred tax liabilities: Depreciation ($98.6 ) ($101.4 ) Inventory (24.3 ) (9.9 ) Convertible debt (1.7 ) (2.6 ) Lease liability (3.4 ) — Other, net (0.7 ) (0.7 ) Deferred tax liabilities ($128.7 ) ($114.6 ) Deferred tax assets: Pension and postretirement benefits $47.9 $55.2 Other employee benefit accruals 7.2 7.1 Tax loss carryforwards 86.0 82.0 Intangible assets 1.1 1.1 Inventory 5.4 1.2 State decoupling 4.5 5.1 Leases - right-of-use asset 3.4 — Interest limitation 6.0 3.2 Other, net 1.2 2.6 Deferred tax assets subtotal $162.7 $157.5 Valuation allowances (34.9 ) (43.7 ) Deferred tax assets 127.8 113.8 Net deferred tax assets (liabilities) ($0.9 ) ($0.8 )

Earnings (Loss) Per Share (Tabl

Earnings (Loss) Per Share (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table sets forth the reconciliation of the numerator and the denominator of basic and diluted loss per share for the years ended December 31, 2019 , 2018 and 2017 : Year Ended December 31, 2019 2018 ADJUSTED 2017 ADJUSTED Numerator: Net income (loss) ($110.0 ) ($10.0 ) ($31.3 ) Denominator: Weighted average shares outstanding, basic 44.8 44.6 44.4 Weighted average shares outstanding, diluted 44.8 44.6 44.4 Basic earnings (loss) per share ($2.46 ) ($0.22 ) ($0.70 ) Diluted earnings (loss) per share ($2.46 ) ($0.22 ) ($0.70 )

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2019
Inventory Disclosure [Abstract]
Schedule of Components of Inventory	The components of inventories as of December 31, 2019 and 2018 were as follows: December 31, 2019 2018 ADJUSTED Manufacturing supplies $49.8 $46.9 Raw materials 26.0 35.2 Work in process 123.7 155.7 Finished products 93.1 142.8 Gross inventory 292.6 380.6 Allowance for inventory reserves (10.7 ) (6.1 ) Total inventories, net $281.9 $374.5

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	The components of property, plant and equipment, net as of December 31, 2019 and 2018 were as follows: December 31, 2019 2018 Land $13.3 $14.1 Buildings and improvements 419.0 424.4 Machinery and equipment 1,404.6 1,404.2 Construction in progress 30.9 28.5 Subtotal 1,867.8 1,871.2 Less allowances for depreciation (1,241.4 ) (1,196.8 ) Property, plant and equipment, net $626.4 $674.4

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Finite-Lived Intangible Assets	The components of intangible assets, net as of December 31, 2019 and 2018 were as follows: December 31, 2019 December 31, 2018 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Customer relationships $6.3 $5.0 $1.3 $6.3 $4.6 $1.7 Technology use 9.0 8.0 1.0 9.0 6.5 2.5 Capitalized software 61.1 49.1 12.0 61.6 48.0 13.6 Total intangible assets $76.4 $62.1 $14.3 $76.9 $59.1 $17.8

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Lease, Cost	The Company recorded lease cost for the year ended December 31, 2019 as follows: Year Ended December 31, 2019 Operating lease cost $7.4 Short-term lease cost 1.9 Total lease cost $9.3 Supplemental cash flow information related to leases was as follows: Year Ended December 31, 2019 Cash paid for amounts included in the measurement of operating lease liabilities $7.5 Right-of-use assets obtained in exchange for operating lease obligations $4.3
Future Lease Maturity	Future minimum lease payments under non-cancellable leases as of December 31, 2019 were as follows: 2020 $6.8 2021 4.6 2022 2.2 2023 1.3 After 2023 0.5 Total future minimum lease payments 15.4 Less amount of lease payment representing interest (1.0 ) Total present value of lease payments $14.4
Future Lease Maturity	Future minimum lease payments under non-cancellable leases as of December 31, 2018 were as follows: 2019 $6.3 2020 5.2 2021 3.3 2022 1.0 2023 0.6 After 2023 — Total future minimum lease payments $16.4

Financing Arrangements (Tables)

Financing Arrangements (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Schedule of Components of Convertible Notes	The components of the Convertible Notes as of December 31, 2019 and December 31, 2018 were as follows: Year Ended December 31, 2019 2018 Principal $86.3 $86.3 Less: Debt issuance costs, net of amortization (0.7 ) (1.2 ) Less: Debt discount, net of amortization (7.0 ) (11.0 ) Convertible notes, net $78.6 $74.1
Schedule of Interest Expense	The following table sets forth total interest expense recognized related to the Convertible Notes: Year Ended December 31, 2019 2018 Contractual interest expense $5.2 $5.2 Amortization of debt issuance costs 0.4 0.4 Amortization of debt discount 4.0 3.6 Total $9.6 $9.2

Retirement and Postretirement_2

Retirement and Postretirement Benefits (Tables)	12 Months Ended
	Dec. 31, 2019
Defined Benefit Plan [Abstract]
Schedule of Defined Benefit Plans Disclosures	The following tables set forth the change in benefit obligation, change in plan assets, funded status and amounts recognized on the Consolidated Balance Sheets for the defined benefit pension plans as of December 31, 2019 and 2018 : Pension Postretirement Change in benefit obligation: 2019 2018 2019 2018 Benefit obligation at the beginning of year $1,178.3 $1,282.1 $194.7 $216.2 Service cost 17.4 17.2 1.1 1.6 Interest cost 48.9 45.6 5.9 7.6 Actuarial (gains) losses 145.7 (70.4 ) 11.4 (11.7 ) Benefits paid (72.3 ) (92.4 ) (14.4 ) (19.0 ) Plan amendment (0.7 ) 0.5 (72.5 ) — Curtailments (8.9 ) — — — Foreign currency translation adjustment 3.0 (4.3 ) — — Benefit obligation at the end of year $1,311.4 $1,178.3 $126.2 $194.7 Pension Postretirement Change in plan assets: 2019 2018 2019 2018 Fair value of plan assets at the beginning of year $1,054.4 $1,186.6 $86.1 $104.0 Actual return on plan assets 167.7 (45.5 ) 8.9 (1.3 ) Company contributions / payments 2.0 10.6 1.7 2.4 Benefits paid (72.3 ) (92.4 ) (14.4 ) (19.0 ) Foreign currency translation adjustment 3.6 (4.9 ) — — Fair value of plan assets at end of year $1,155.4 $1,054.4 $82.3 $86.1 Funded status at end of year ($156.0 ) ($123.9 ) ($43.9 ) ($108.6 )
Schedule of Amounts Recognized in Balance Sheet	Amounts recognized on the balance sheet at December 31, 2019 and 2018 , for TimkenSteel’s pension and postretirement benefit plans include: Pension Postretirement 2019 2018 2019 2018 Non-current assets $25.2 $10.5 $— $— Current liabilities (0.6 ) (0.6 ) (2.4 ) (2.4 ) Non-current liabilities (180.6 ) (133.8 ) (41.5 ) (106.2 ) Total ($156.0 ) ($123.9 ) ($43.9 ) ($108.6 )
Schedule of Amounts Recognized in Other Comprehensive Income (Loss)	Included in accumulated other comprehensive loss at December 31, 2019 and 2018 , were the following before-tax amounts that had not been recognized in net periodic benefit cost: Pension Postretirement 2019 2018 2019 2018 Unrecognized prior service (benefit) cost $0.5 $1.6 ($67.8 ) $0.9
Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) to be Recognized over Next Fiscal Year	Amounts expected to be amortized from accumulated other comprehensive loss (income) and included in total net periodic benefit cost during the year ended December 31, 2020 are as follows: Pension Postretirement Prior service (benefit) cost $0.3 ($6.0 )
Schedule of Assumptions Used	The weighted average assumptions used in determining benefit obligation as of December 31, 2019 and 2018 were as follows: Pension Postretirement Assumptions: 2019 2018 2019 2018 Discount rate 3.42 % 4.30 % 3.42 % 4.34 % Future compensation assumption 2.32 % 2.36 % n/a n/a The weighted average assumptions used in determining benefit cost for the years ended December 31, 2019 and 2018 were as follows: Pension Postretirement Assumptions: 2019 2018 2019 2018 Discount rate (1) 4.30 % 3.68 % 4.34% /3.94% 3.66 % Future compensation assumption 2.36 % 2.37 % n/a n/a Expected long-term return on plan assets 6.41 % 6.45 % 5.00 % 5.00 %
Schedule of Periodic Benefit Cost	The components of net periodic benefit cost (income) for the years ended December 31, 2019 , 2018 and 2017 were as follows: Pension Postretirement Years Ended December 31, Years Ended December 31, Components of net periodic benefit cost (income): 2019 2018 2017 2019 2018 2017 Service cost $17.4 $17.2 $18.2 $1.1 $1.6 $1.6 Interest cost 48.9 45.6 49.1 5.9 7.6 $8.4 Expected return on plan assets (65.0 ) (74.0 ) (70.7 ) (3.9 ) (4.8 ) (5.2 ) Amortization of prior service cost 0.4 0.5 0.5 (3.8 ) 0.2 1.0 Curtailment (8.9 ) — — — — — Net remeasurement losses (gains) 43.1 49.1 12.5 6.4 (5.6 ) 9.3 Net Periodic Benefit Cost (Income) $35.9 $38.4 $9.6 $5.7 ($1.0 ) $15.1
Schedule of Allocation of Plan Assets	The following table presents the fair value hierarchy for those investments of TimkenSteel’s pension assets measured at fair value on a recurring basis as of December 31, 2019 : Total Level 1 Level 2 Level 3 Assets: Cash and cash equivalents $12.2 $0.9 $11.3 $— U.S government and agency securities 250.3 246.1 4.2 — Corporate bonds 102.7 — 102.7 — Equity securities 49.8 49.8 — — Mutual fund - fixed income 56.4 56.4 — — Total Assets in the fair value hierarchy $471.4 $353.2 $118.2 $— Assets measured at net asset value (1) 684.0 — — — Total Assets $1,155.4 $353.2 $118.2 $— (1) Certain assets that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. Such assets include common collective trusts that invest in equity securities and fixed income securities, limited partnerships, real estate partnerships, hedge funds, and risk parity investments. As of December 31, 2019 , these assets are redeemable at net asset value within 90 days. The following table presents the fair value hierarchy for those investments of TimkenSteel’s pension assets measured at fair value on a recurring basis as of December 31, 2018 : Total Level 1 Level 2 Level 3 Assets: Cash and cash equivalents $22.5 $0.6 $21.9 $— U.S government and agency securities 234.2 229.1 5.1 — Corporate bonds 97.4 — 97.4 — Equity securities 37.1 37.1 — — Mutual fund - fixed income 33.1 33.1 — — Mutual fund - real estate 7.7 7.7 — — Total Assets in the fair value hierarchy $432.0 $307.6 $124.4 $— Assets measured at net asset value (1) 622.4 — — — Total Assets $1,054.4 $307.6 $124.4 $— (1) Certain assets that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. Such assets include common collective trusts that invest in equity securities and fixed income securities, limited partnerships, real estate partnerships, and risk parity investments. As of December 31, 2018 , these assets were redeemable at net asset value within 90 days. The following table presents the fair value hierarchy for those investments of TimkenSteel’s postretirement assets measured at fair value on a recurring basis as of December 31, 2019 : Total Level 1 Level 2 Level 3 Assets: Cash and cash equivalents $3.0 $3.0 $— $— Mutual fund - fixed income 15.8 15.8 — — Total Assets in the fair value hierarchy $18.8 $18.8 $— $— Assets measured at net asset value (1) 63.5 — — — Total Assets $82.3 $18.8 $— $— (1) Certain assets that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. Such assets include common collective trusts that invest in equity securities and fixed income securities, limited partnerships, real estate partnerships, hedge funds, and risk parity investments. As of December 31, 2019 , these assets are redeemable at net asset value within 90 days. The following table presents the fair value hierarchy for those investments of TimkenSteel’s postretirement assets measured at fair value on a recurring basis as of December 31, 2018 : Total Level 1 Level 2 Level 3 Assets: Cash and cash equivalents $5.6 $5.6 $— $— Mutual fund - fixed income 8.9 8.9 — — Total Assets in the fair value hierarchy $14.5 $14.5 $— $— Assets measured at net asset value (1) 71.6 — — — Total Assets $86.1 $14.5 $— $— (1) Certain assets that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. Such assets include common collective trusts that invest in equity securities and fixed income securities, limited partnerships, real estate partnerships, and risk parity investments. As of December 31, 2018 , these assets were redeemable at net asset value within 90 days.
Schedule of Expected Benefit Payments	Future benefit payments are expected to be as follows: Benefit Payments: Pension Postretirement 2020 $78.8 $11.9 2021 79.2 11.0 2022 85.6 10.3 2023 76.5 9.6 2024 76.0 9.0 2025-2029 374.3 39.3

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	The following table provides the significant assumptions used to calculate the grant date fair market values of options granted using a Black-Scholes option pricing method: 2019 2018 2017 Weighted-average fair value per option $5.54 $7.46 $7.68 Risk-free interest rate 2.63% 2.77% 2.21% Dividend yield —% —% —% Expected stock volatility 41.36% 41.67% 43.23% Expected life - years 6 6 6
Share-based Compensation, Stock Options, Activity	The following summarizes TimkenSteel stock option activity from January 1, 2019 to December 31, 2019: Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (millions) Outstanding as of December 31, 2018 2,532,669 $21.33 Granted 329,720 $12.45 Exercised (25,039 ) $8.83 Canceled, forfeited or expired (195,780 ) $17.33 Outstanding as of December 31, 2019 2,641,570 $20.64 5.27 $0.2 Options expected to vest 403,774 $13.43 8.30 $— Options exercisable 2,237,796 $21.94 4.73 $0.2 Stock options presented in this table represent TimkenSteel awards only, including those held by The Timken Company employees.
Nonvested Restricted Stock Shares Activity	The following summarizes TimkenSteel stock-settled restricted share award activity from January 1, 2019 to December 31, 2019: Number of Shares Weighted Average Grant Date Fair Value Outstanding as of December 31, 2018 817,884 $14.15 Granted 833,220 $9.86 Vested (365,800 ) $10.23 Canceled, forfeited or expired (111,635 ) $13.79 Outstanding as of December 31, 2019 1,173,669 $11.94 Restricted share awards presented in this table represent TimkenSteel awards only, including those held by The Timken Company employees.

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	Changes in accumulated other comprehensive income (loss) for the years ended December 31, 2019 and 2018 by component were as follows: Foreign Currency Translation Adjustments Pension and Postretirement Liability Adjustments Total Balance as of December 31, 2018 ($7.3 ) ($1.6 ) ($8.9 ) Other comprehensive income before reclassifications, before income tax 0.5 — 0.5 Amounts reclassified from accumulated other comprehensive income (loss), before income tax — (2.4 ) (2.4 ) Amounts deferred to accumulated other comprehensive income (loss), before income tax — 72.2 72.2 Tax effect — (16.7 ) (16.7 ) Net current period other comprehensive income, net of income taxes 0.5 53.1 53.6 Balance as of December 31, 2019 ($6.8 ) $51.5 $44.7 Foreign Currency Translation Adjustments Pension and Postretirement Liability Adjustments Total Balance at December 31, 2017 ($5.9 ) ($1.7 ) ($7.6 ) Other comprehensive income before reclassifications, before income tax (1.4 ) (0.5 ) (1.9 ) Amounts reclassified from accumulated other comprehensive loss, before income tax — 0.7 0.7 Tax effect — (0.1 ) (0.1 ) Net current period other comprehensive income, net of income taxes (1.4 ) 0.1 (1.3 ) Balance as of December 31, 2018 ($7.3 ) ($1.6 ) ($8.9 )

Selected Quarterly Financial _2

Selected Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Data	The following selected quarterly operating results for each quarter of fiscal 2019 and 2018 have been adjusted to reflect the change in accounting principle as described in “ Note 1 - Basis of Presentation ”: Quarters ended December 31, 2019 September 30. 2019 As Reported Adjustments As Adjusted Net sales $226.9 $274.2 $— $274.2 Gross profit (18.0 ) 13.2 (15.8 ) (2.6 ) Net income (loss) (84.6 ) (4.6 ) (12.4 ) (17.0 ) Per share data: Basic earnings (loss) per share ($1.89 ) ($0.10 ) ($0.28 ) ($0.38 ) Diluted earnings (loss) per share ($1.89 ) ($0.10 ) ($0.28 ) ($0.38 ) Quarters ended June 30, 2019 March 31, 2019 As Reported Adjustments As Adjusted As Reported Adjustments As Adjusted Net sales $336.7 $— $336.7 $371.0 $— $371.0 Gross profit 25.4 (10.6 ) 14.8 29.1 (0.7 ) 28.4 Net income (loss) (4.4 ) (7.5 ) (11.9 ) 4.2 (0.7 ) 3.5 Per share data: Basic earnings (loss) per share ($0.10 ) ($0.17 ) ($0.27 ) $0.09 ($0.01 ) $0.08 Diluted earnings (loss) per share ($0.10 ) ($0.17 ) ($0.27 ) $0.09 ($0.01 ) $0.08 Quarters ended December 31, 2018 September 30, 2018 As Reported Adjustments As Adjusted As Reported Adjustments As Adjusted Net sales $406.4 $— $406.4 $409.9 $— $409.9 Gross profit 27.1 10.2 37.3 24.6 3.8 28.4 Net income (loss) (39.6 ) 10.2 (29.4 ) 1.4 3.8 5.2 Per share data: Basic earnings (loss) per share ($0.89 ) $0.23 ($0.66 ) $0.03 $0.09 $0.12 Diluted earnings (loss) per share ($0.89 ) $0.23 ($0.66 ) $0.03 $0.09 $0.12 Quarters ended June 30, 2018 March 31, 2018 As Reported Adjustments As Adjusted As Reported Adjustments As Adjusted Net sales $413.5 $— $413.5 $380.8 $— $380.8 Gross profit 32.1 6.4 38.5 21.1 1.3 22.4 Net income (loss) 8.4 6.4 14.8 (1.9 ) 1.3 (0.6 ) Per share data: Basic earnings (loss) per share $0.19 $0.14 $0.33 ($0.04 ) $0.03 ($0.01 ) Diluted earnings (loss) per share $0.19 $0.14 $0.33 ($0.04 ) $0.03 ($0.01 )

Basis of Presentation Narrative

Basis of Presentation Narrative (Details) - T T in Millions	12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Annual Melt Capacity	2
Annual Shipment Capacity	1.5
Percentage of LIFO inventory		70.00%

Basis of Presentation Schedule

Basis of Presentation Schedule of Change In Accounting Principle (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2018	Jan. 01, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of products sold									$ 1,186.2	$ 1,484	$ 1,248.9
Gross Profit	$ (18)	$ (2.6)	$ 14.8	$ 28.4	$ 37.3	$ 28.4	$ 38.5	$ 22.4	22.6	126.6	80.3
Income (Loss) Before Income Taxes									(126.1)	(8.2)	(29.8)
Net income (loss)	$ (84.6)	$ (17)	$ (11.9)	$ 3.5	$ (29.4)	$ 5.2	$ 14.8	$ (0.6)	$ (110)	$ (10)	$ (31.3)
Basic earnings (loss) per share (in dollars per share)	$ (1.89)	$ (0.38)	$ (0.27)	$ 0.08	$ (0.66)	$ 0.12	$ 0.33	$ (0.01)	$ (2.46)	$ (0.22)	$ (0.70)
Diluted earnings (loss) per share (in dollars per share)	$ (1.89)	$ (0.38)	$ (0.27)	$ 0.08	$ (0.66)	$ 0.12	$ 0.33	$ (0.01)	$ (2.46)	$ (0.22)	$ (0.70)
Retained deficit	$ (301.5)				$ (191.5)				$ (301.5)	$ (191.5)			$ 150.4
Inventories, net	281.9				374.5				281.9	374.5
Other comprehensive income (loss)									53.6	(1.3)	$ 1.8
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									(56.4)	(11.3)	(29.5)
Cumulative effect of change in accounting principle												$ 0.7	43.5
Inventories, net									92.6	(94.5)	(72.3)
Previous Accounting Method
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of products sold									1,160.5	1,505.7	1,261.4
Gross Profit									48.3	104.9	67.8
Income (Loss) Before Income Taxes									(100.4)	(29.9)	(42.3)
Net income (loss)									$ (84.3)	$ (31.7)	$ (43.8)
Basic earnings (loss) per share (in dollars per share)									$ (1.89)	$ (0.71)	$ (0.99)
Diluted earnings (loss) per share (in dollars per share)									$ (1.89)	$ (0.71)	$ (0.99)
Retained deficit	(249.4)				(269.2)				$ (249.4)	$ (269.2)			$ 193.9
Inventories, net	229.8				296.8				229.8	296.8
Other comprehensive income (loss)										(33)	$ (42)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									(30.7)
Inventories, net									66.9	(72.8)	(59.8)
Effect of Change
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of products sold									25.7	(21.7)	(12.5)
Gross Profit									(25.7)	21.7	12.5
Income (Loss) Before Income Taxes									(25.7)	21.7	12.5
Net income (loss)									$ (25.7)	$ 21.7	$ 12.5
Basic earnings (loss) per share (in dollars per share)									$ (0.57)	$ 0.49	$ 0.29
Diluted earnings (loss) per share (in dollars per share)									$ (0.57)	$ 0.49	$ 0.29
Retained deficit	(52.1)				77.7				$ (52.1)	$ 77.7
Inventories, net	$ 52.1				$ 77.7				52.1	77.7
Other comprehensive income (loss)										21.7	$ 12.5
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									(25.7)
Inventories, net									$ 25.7	$ (21.7)	$ (12.5)

Significant Accounting Polici_4

Significant Accounting Policies - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019	Jan. 01, 2018	Jan. 01, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Impairment charges and loss on sale or disposal of assets	$ 9.3	$ 0.9	$ 0.7
Foreign currency exchange gains (losses)	0	0.2	(0.3)
Revenue recognition accounting standard adoption					$ 0.7	$ 43.5
Research and development	4.1	$ 8.1	$ 8
Lease liabilities	14.4
Operating lease right-of-use assets	$ 14.3
Building
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Useful lives of property, plant and equipment, net	P30Y
Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Useful lives of intangible asses, net	3 years
Minimum | Machinery and Equipment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Useful lives of property, plant and equipment, net	P3Y
Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Useful lives of intangible asses, net	15 years
Maximum | Machinery and Equipment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Useful lives of property, plant and equipment, net	P20Y
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lease liabilities				$ 16
Operating lease right-of-use assets				$ 16
Retained Deficit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue recognition accounting standard adoption					$ 0.7	$ 43.5

Segment Information (Details)

Segment Information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 226.9	$ 274.2	$ 336.7	$ 371	$ 406.4	$ 409.9	$ 413.5	$ 380.8	$ 1,208.8	$ 1,610.6	$ 1,329.2
Long-lived assets, net	655				692.2				655	692.2
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									1,096.8	1,456.2	1,207.7
Long-lived assets, net	654.8				692				654.8	692
Foreign
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									112	154.4	$ 121.5
Long-lived assets, net	$ 0.2				$ 0.2				$ 0.2	$ 0.2

Revenue Recognition (Details)

Revenue Recognition (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Net sales	$ 226.9	$ 274.2	$ 336.7	$ 371	$ 406.4	$ 409.9	$ 413.5	$ 380.8	$ 1,208.8	$ 1,610.6	$ 1,329.2
Bar
Disaggregation of Revenue [Line Items]
Net sales									783	1,030.7	850
Tube
Disaggregation of Revenue [Line Items]
Net sales									151.8	254.7	176.9
Value-add
Disaggregation of Revenue [Line Items]
Net sales									240.6	284.3	265.3
Other
Disaggregation of Revenue [Line Items]
Net sales									33.4	40.9	37
Mobile
Disaggregation of Revenue [Line Items]
Net sales									479.3	553.9	528.6
Industrial
Disaggregation of Revenue [Line Items]
Net sales									486.3	637.5	486.4
Energy
Disaggregation of Revenue [Line Items]
Net sales									166.4	265.6	141.7
Other
Disaggregation of Revenue [Line Items]
Net sales									$ 76.8	$ 153.6	$ 172.5

Restructuring Charges - Narrat

Restructuring Charges - Narrative (Details)	12 Months Ended
	Dec. 31, 2019USD ($)Positions	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Restructuring and Related Activities [Abstract]
Number of positions eliminated | Positions	150
Restructuring charges	$ 8,600,000	$ 0	$ 0
Accelerated restructuring charges	$ 300,000

Restructuring Charges - Summary

Restructuring Charges - Summary of Restructuring Reserve (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Reserve [Roll Forward]
Beginning balance	$ 0
Expenses	8,600,000	$ 0	$ 0
Payments	(2,600,000)
Ending balance	$ 6,000,000	$ 0

Disposition of Non-Core Asset_2

Disposition of Non-Core Assets (Details) - USD ($)	2 Months Ended	3 Months Ended	12 Months Ended
	Feb. 27, 2020	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment charges and loss on sale or disposal of assets			$ 9,300,000	$ 900,000	$ 700,000
Restructuring charges			8,600,000	$ 0	$ 0
Disposal Group, Held-for-sale, Not Discontinued Operation
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment charges and loss on sale or disposal of assets		$ 7,300,000
Restructuring charges		700,000
Inventory write-down		4,800,000
Accelerated depreciation		2,800,000
Scrap Processing Facility | Disposal Group, Held-for-sale, Not Discontinued Operation
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal group consideration		4,000,000	$ 4,000,000
Inventories | Disposal Group, Held-for-sale, Not Discontinued Operation
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment charges and loss on sale or disposal of assets		$ 11,300,000
Subsequent Event | Disposal Group, Held-for-sale, Not Discontinued Operation
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accelerated depreciation	$ 1,600,000

Other Income, Net (Details)

Other Income, Net (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other Income and Expenses [Abstract]
Unrecognized Tax Benefits		$ 0	$ 0	$ 0
Pension and postretirement non-service benefit income		17,500,000	25,200,000	17,500,000
Loss from remeasurement of benefit plans	$ (4,400,000)	(40,600,000)	(43,500,000)	(21,800,000)
Foreign currency exchange gain (loss)		0	(200,000)	300,000
Miscellaneous income (expense)		(200,000)	(100,000)	(100,000)
Total other income (expense), net		(23,300,000)	(18,600,000)	(4,100,000)
Curtailments		8,900,000
Unrecognized Tax Benefits that Would Impact Effective Tax Rate		0	0	0
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued		$ 0	$ 0	$ 0

Income Tax Provision - Narrativ

Income Tax Provision - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Undistributed Earnings of Foreign Subsidiaries	$ 6,500,000	$ 5,500,000	$ 2,900,000
Deferred Tax Liabilities, Undistributed Foreign Earnings	700,000	600,000
Deferred income taxes	900,000	800,000
Operating Loss Carryforwards	370,100,000
Operating Loss Carryforwards, Valuation Allowance	34,900,000
Disallowed Business Interest Carryforward	25,200,000
Unrecognized Tax Benefits	0	0	0
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	0	0	0
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	0	0	$ 0
United States
Operating Loss Carryforwards [Line Items]
Income Taxes Paid	0	0
Operating Loss Carryforwards	314,900,000
State
Operating Loss Carryforwards [Line Items]
Income Taxes Paid	200,000	200,000
Income Taxes Receivable, Current		0
Foreign
Operating Loss Carryforwards [Line Items]
Income Taxes Paid	600,000	$ 600,000
Operating Loss Carryforwards	$ 55,200,000

Income Tax Provision - Income f

Income Tax Provision - Income from Operations Before Income Taxes Based on Geographic Location of Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
United States	$ (130.8)	$ (10.1)	$ (37)
Non-United States	4.7	1.9	7.2
Income (Loss) Before Income Taxes	$ (126.1)	$ (8.2)	$ (29.8)

Income Tax Provision - (Benefit

Income Tax Provision - (Benefit) Provision for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
Federal	$ 0	$ 0	$ 1.1
State and local	0.1	0.3	0.1
Foreign	0.4	0.7	0.6
Current tax provision (benefit)	0.5	1	1.8
Deferred:
Federal	(14.4)	0.4	(0.4)
State and local	(2)	0	0
Foreign	(0.2)	0.4	0.1
Deferred tax provision (benefit)	(16.6)	0.8	(0.3)
Provision (benefit) for incomes taxes	$ (16.1)	$ 1.8	$ 1.5

Income Tax Provision - Reconci

Income Tax Provision - Reconciliation Between Effective Tax Rate and Statutory Rate (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Tax at the U.S. federal statutory rate	$ (26.5)	$ (6.3)	$ (14.8)
Adjustments:
State and local income taxes, net of federal tax benefit	(1.3)	(0.5)	(0.7)
Foreign earnings taxed at different rates	0	0.2	(0.2)
U.S. research tax credit	0.2	(0.2)	(0.2)
Valuation allowance	10.2	7.5	6.3
Global intangible low-taxed income	0.2	0.5	0
Tax Reform impact - transition tax and rate change	0	0	10.2
Permanent differences	1.3	0.8	0.3
Other items, net	(0.2)	(0.2)	0.6
Provision (benefit) for incomes taxes	$ (16.1)	$ 1.8	$ 1.5
Effective tax rate	12.80%	(5.90%)	(3.70%)

Income Tax Provision - Effect

Income Tax Provision - Effect of Temporary Differences Giving Rise to Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Deferred tax liabilities:
Depreciation	$ (98.6)	$ (101.4)
Inventory	(24.3)	(9.9)
Convertible debt	(1.7)	(2.6)
Lease liability	(3.4)	0
Other, net	(0.7)	(0.7)
Deferred tax liabilities subtotal	(128.7)	(114.6)
Deferred tax assets:
Pension and postretirement benefits	47.9	55.2
Other employee benefit accruals	7.2	7.1
Tax loss carryforwards	86	82
Intangible assets	1.1	1.1
Inventory	5.4	1.2
State decoupling	4.5	5.1
Leases - right-of-use asset	3.4	0
Interest limitation	6	3.2
Other, net	1.2	2.6
Deferred tax assets subtotal	162.7	157.5
Valuation allowances	(34.9)	(43.7)
Deferred tax assets	127.8	113.8
Net deferred tax assets (liabilities)	$ (0.9)	$ (0.8)

Earnings (Loss) Per Share - Sch

Earnings (Loss) Per Share - Schedule of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Numerator:
Net income (loss)	$ (84.6)	$ (17)	$ (11.9)	$ 3.5	$ (29.4)	$ 5.2	$ 14.8	$ (0.6)	$ (110)	$ (10)	$ (31.3)
Denominator:
Weighted average shares outstanding, basic (in shares)									44.8	44.6	44.4
Weighted average shares outstanding, diluted (in shares)									44.8	44.6	44.4
Basic earnings (loss) per share (in dollars per share)	$ (1.89)	$ (0.38)	$ (0.27)	$ 0.08	$ (0.66)	$ 0.12	$ 0.33	$ (0.01)	$ (2.46)	$ (0.22)	$ (0.70)
Diluted earnings (loss) per share (in dollars per share)	$ (1.89)	$ (0.38)	$ (0.27)	$ 0.08	$ (0.66)	$ 0.12	$ 0.33	$ (0.01)	$ (2.46)	$ (0.22)	$ (0.70)
Stock Compensation Plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation									3.7	3.3	3.1
Convertible Debt Securities [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation									6.9	6.9	6.9

Inventories - Schedule of Inven

Inventories - Schedule of Inventory (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Manufacturing supplies	$ 49.8	$ 46.9
Raw materials	26	35.2
Work in process	123.7	155.7
Finished products	93.1	142.8
Gross inventory	292.6	380.6
Allowance for inventory reserves	(10.7)	(6.1)
Total inventories, net	$ 281.9	$ 374.5

Inventories - Narrative (Detail

Inventories - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Inventory [Line Items]
Inventory valuation reserves	$ 10.7	$ 6.1
Scrap Processing Facility
Inventory [Line Items]
Inventory valuation reserves	$ 4.8

Property, Plant and Equipment -

Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Land	$ 13.3	$ 14.1
Buildings and improvements	419	424.4
Machinery and equipment	1,404.6	1,404.2
Construction in progress	30.9	28.5
Subtotal	1,867.8	1,871.2
Less allowances for depreciation	(1,241.4)	(1,196.8)
Property, plant and equipment, net	$ 626.4	$ 674.4

Property, Plant and Equipment_2

Property, Plant and Equipment - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Depreciation	$ 67.4	$ 67.5	$ 68.3
Accelerated depreciation	1.9
Impairment charges and loss on sale	$ 9	$ 0.5	$ 0.7

Intangible Assets - Schedule of

Intangible Assets - Schedule of Intangible Assets (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 76.4	$ 76.9
Accumulated Amortization	62.1	59.1
Net Carrying Amount	14.3	17.8
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	6.3	6.3
Accumulated Amortization	5	4.6
Net Carrying Amount	1.3	1.7
Technology use
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	9	9
Accumulated Amortization	8	6.5
Net Carrying Amount	1	2.5
Capitalized software
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	61.1	61.6
Accumulated Amortization	49.1	48
Net Carrying Amount	$ 12	$ 13.6

Intangible Assets - Narrative (

Intangible Assets - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Weighted average remaining useful life	8 years
Amortization expense for intangible assets	$ 6.1	$ 5.5	$ 6.6
Accelerated amortization expense	0.9
Loss on disposal of intangibles	$ 0.1
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted average remaining useful life	15 years
Technology Use
Finite-Lived Intangible Assets [Line Items]
Weighted average remaining useful life	15 years
Capitalized software
Finite-Lived Intangible Assets [Line Items]
Weighted average remaining useful life	6 years
Impairment charges	$ 0	$ 0.4

Intangible Assets Intangible As

Intangible Assets Intangible Assets - Expected Amortization Expense (Details)	Dec. 31, 2019USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2020	$ 3.3
2021	2
2022	1.8
2023	1.7
2024	$ 0.8

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Lessee, Lease, Description [Line Items]
Extension term	1 year
Weighted average remaining lease term for operating leases	2 years 10 months 24 days
Weighted average discount rate used to measure operating lease liabilities	4.50%
Leases not yet commenced	$ 7.6
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease term	1 year
Leases not yet commenced, term	3 years
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term	6 years
Leases not yet commenced, term	4 years

Leases - Lease Cost (Details)

Leases - Lease Cost (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Leases [Abstract]
Operating lease cost	$ 7.4
Short-term lease cost	1.9
Total lease cost	$ 9.3

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Leases [Abstract]
Cash paid for amounts included in the measurement of operating lease liabilities	$ 7.5
Right-of-use assets obtained in exchange for operating lease obligations	$ 4.3

Leases - Future Minimum Lease P

Leases - Future Minimum Lease Payments (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Leases, Operating [Abstract]
2020	$ 6.8
2021	4.6
2022	2.2
2023	1.3
After 2023	0.5
Total future minimum lease payments	15.4
Less amount of lease payment representing interest	(1)
Total present value of lease payments	$ 14.4
2019		$ 6.3
2020		5.2
2021		3.3
2022		1
2023		0.6
After 2023		0
Total future minimum lease payments		$ 16.4

Financing Arrangements - Narrat

Financing Arrangements - Narrative (Details)	Oct. 15, 2019USD ($)	Jan. 23, 2018USD ($)	May 31, 2016USD ($)$ / shares	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Jan. 26, 2018borrowing_request
Debt Instrument [Line Items]
Initial value of principal				$ 78,600,000	$ 74,100,000
Transaction costs, debt				700,000	1,200,000
Revenue refunding bonds repayments				0	30,200,000	$ 0
Interest paid				11,500,000	$ 11,800,000
Third Amended Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, tentative future commitment increase	$ 100,000,000
Line of credit facility, unused capacity, commitment fee percentage	0.25%
Convertible Senior Notes | Convertible Notes
Debt Instrument [Line Items]
Effective interest rate			12.00%
Debt Instrument, Interest Rate, Stated Percentage			6.00%
Debt Instrument, Convertible, Conversion Price | $ / shares			$ 12.58
Debt Instrument, Convertible, Conversion Ratio			0.0795165
Debt Instrument, Convertible, Amounts by Which Instrument Can Be Converted			$ 1,000
Proceeds from Convertible Debt			83,200,000
Initial value of principal			66,900,000
Principal amount allocated to conversion feature			19,400,000
Transaction costs, debt			2,400,000
Transaction costs, equity component of convertible debt			700,000
Fair value of convertible notes				$ 89,300,000
Variable-rate State of Ohio Water Development Revenue Refunding Bonds, maturing on November 1, 2025 | Revenue Refunding Bonds
Debt Instrument [Line Items]
Revenue refunding bonds repayments		$ 12,200,000
Variable-rate State of Ohio Air Quality Development Revenue Refunding Bonds, maturing on November 1, 2025 | Revenue Refunding Bonds
Debt Instrument [Line Items]
Revenue refunding bonds repayments		9,500,000
Variable-rate State of Ohio Pollution Control Revenue Refunding Bonds, maturing on June 1, 2033 | Revenue Refunding Bonds
Debt Instrument [Line Items]
Revenue refunding bonds repayments		$ 8,500,000
Convertible Senior Notes due Twenty Twenty One, Issuance One [Member] | Convertible Notes
Debt Instrument [Line Items]
Debt Instrument, Face Amount			75,000,000
Convertible Senior Notes due Twenty Twenty One, Over-allotment [Member] | Convertible Notes
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 11,300,000
Credit Agreement | Third Amended Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 400,000,000
Line of Credit Facility, Number of Additional Borrowing Capacity Requests Permitted | borrowing_request							2
Effective interest rate				3.30%
Amount available under amended credit agreement				$ 203,200,000
Commercial and Standby Letters of Credit | Third Amended Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, borrowing sublimit	15,000,000
Swingline Loans | Third Amended Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, borrowing sublimit	40,000,000
First In, Last Out (FILO) | Third Amended Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, tentative future commitment increase	$ 30,000,000
Federal Reserve Bank of New York Rate | Swingline Loan | Third Amended Credit Facility [Member]
Debt Instrument [Line Items]
Variable interest rate, spread	0.50%
London Interbank Offered Rate (LIBOR) | Swingline Loan | Third Amended Credit Facility [Member]
Debt Instrument [Line Items]
Variable interest rate, spread	1.00%

Financing Arrangements - Schedu

Financing Arrangements - Schedule of Convertible Debt (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	May 31, 2016
Debt Instrument [Line Items]
Principal	$ 86.3	$ 86.3
Less: Debt issuance costs, net of amortization	(0.7)	(1.2)
Less: Debt discount, net of amortization	(7)	(11)
Net carrying amount	$ 78.6	$ 74.1
Convertible Notes | Convertible Senior Notes
Debt Instrument [Line Items]
Less: Debt issuance costs, net of amortization			$ (2.4)
Net carrying amount			$ 66.9

Financing Arrangements - Sche_2

Financing Arrangements - Schedule of Interest Expense (Details) - Convertible Notes - Convertible Senior Notes - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Contractual interest expense	$ 5.2	$ 5.2
Amortization of debt issuance costs	0.4	0.4
Amortization of debt discount	4	3.6
Total	$ 9.6	$ 9.2

Retirement and Postretirement_3

Retirement and Postretirement Benefits - Narrative (Details) $ in Millions	3 Months Ended		6 Months Ended	12 Months Ended
	Dec. 31, 2019USD ($)plan	Jun. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Dec. 31, 2019USD ($)plan	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit Cost Amortization Period			12 years
Curtailments				$ 8.9
Defined contribution plan cost				7.1	$ 6.3	$ 5.4
Pension Cost and Other Postretirement Benefits Cost (Reversal of Cost), Remeasurement			$ 4.4	40.6	43.5	21.8
Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Curtailments				(8.9)	0	0
Reduction Of Future Liability	$ 0.8
Settlements					26
Retirement plan expenses				$ 3.5	2.2
Number of plans for which the accumulated benefit obligation exceeded the fair value of plan assets | plan	2			2
Benefit obligation for plans which the accumulated benefit obligation exceeded the fair value of plan assets	$ 998.5			$ 998.5
Accumulated benefit obligation for plans which the accumulated benefit obligation exceeded the fair value of plan assets	983.6			983.6
Fair value of plan assets for plan which the accumulated benefit obligation exceeded the fair value of plan assets	817.3			817.3
Accumulated benefit obligation	$ 1,294.5			$ 1,294.5	$ 1,149.8
Medical and Prescription Drug Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Health care cost trend rate	5.75%			5.75%	6.00%
Postretirement
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Accumulated Benefit Obligation, Increase (Decrease) for Plan Amendment		$ (70.2)
Curtailments				$ 0	$ 0	$ 0
Reduction Of Future Liability	$ 8.1
Effect of one percentage increase in health care cost trend rate on benefit obligation				0.3	1.1
Effect of one percentage increase in health care cost trend rate on service and interest rate components				0.1	0.1
Effect of one percentage decrease in health care cost trend rate on benefit obligation				0.2	1
Effect of one percentage decrease in health care cost trend rate on service and interest cost components				0.1	$ 0.1
Wellfare Benefit Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Reduction Of Future Liability	2.3
Equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target asset allocation					21.00%
Debt Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target asset allocation					61.00%
Other Investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target asset allocation					18.00%
U.K. | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected contributions in next fiscal year	$ 1.3			$ 1.3

Retirement and Postretirement_4

Retirement and Postretirement Benefits - Change in Benefit Obligations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Change in benefit obligation:
Curtailments	$ 8.9
Pension
Change in benefit obligation:
Benefit obligation at the beginning of year	1,178.3	$ 1,282.1
Service cost	17.4	17.2	$ 18.2
Interest cost	48.9	45.6	49.1
Actuarial (gains) losses	145.7	(70.4)
Benefits paid	(72.3)	(92.4)
Plan amendment	(0.7)	0.5
Curtailments	(8.9)	0	0
Foreign currency translation adjustment	3	(4.3)
Benefit obligation at the end of year	1,311.4	1,178.3	1,282.1
Postretirement
Change in benefit obligation:
Benefit obligation at the beginning of year	194.7	216.2
Service cost	1.1	1.6	1.6
Interest cost	5.9	7.6	8.4
Actuarial (gains) losses	11.4	(11.7)
Benefits paid	(14.4)	(19)
Plan amendment	(72.5)	0
Curtailments	0	0	0
Foreign currency translation adjustment	0	0
Benefit obligation at the end of year	$ 126.2	$ 194.7	$ 216.2

Retirement and Postretirement_5

Retirement and Postretirement Benefits - Change in Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Pension
Change in plan assets:
Fair value of plan assets at the beginning of year	$ 1,054.4	$ 1,186.6
Actual return on plan assets	167.7	(45.5)
Company contributions / payments	2	10.6
Benefits paid	(72.3)	(92.4)
Foreign currency translation adjustment	3.6	(4.9)
Fair value of plan assets at end of year	1,155.4	1,054.4
Funded status at end of year	(156)	(123.9)
Postretirement
Change in plan assets:
Fair value of plan assets at the beginning of year	86.1	104
Actual return on plan assets	8.9	(1.3)
Company contributions / payments	1.7	2.4
Benefits paid	(14.4)	(19)
Foreign currency translation adjustment	0	0
Fair value of plan assets at end of year	82.3	86.1
Funded status at end of year	$ (43.9)	$ (108.6)

Retirement and Postretirement_6

Retirement and Postretirement Benefits - Amounts Recognized in the Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Non-current assets	$ 25.2	$ 10.5
Current liabilities	(3)	(3)
Non-current liabilities	(222.1)	(240)
Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Non-current assets	25.2	10.5
Current liabilities	(0.6)	(0.6)
Non-current liabilities	(180.6)	(133.8)
Total assets (liabilities) recognized	(156)	(123.9)
Postretirement
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Non-current assets	0	0
Current liabilities	(2.4)	(2.4)
Non-current liabilities	(41.5)	(106.2)
Total assets (liabilities) recognized	$ (43.9)	$ (108.6)

Retirement and Postretirement_7

Retirement and Postretirement Benefits - Amounts Recognized in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Unrecognized prior service cost	$ 0.5	$ 1.6
Postretirement
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Unrecognized prior service cost	$ (67.8)	$ 0.9

Retirement and Postretirement_8

Retirement and Postretirement Benefits - Amounts Expected to be Amortized from Accumulated Other Comprehensive Loss in Next Fiscal Year (Details) $ in Millions	Dec. 31, 2019USD ($)
Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Prior service cost	$ 0.3
Postretirement
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Prior service cost	$ (6)

Retirement and Postretirement_9

Retirement and Postretirement Benefits - Weighted Average Assumptions (Details)	4 Months Ended	8 Months Ended	12 Months Ended
	Apr. 30, 2019	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Pension
Benefit Obligation
Discount rate		3.42%	3.42%	4.30%
Future compensation assumption		2.32%	2.32%	2.36%
Benefit Cost
Discount rate			4.30%	3.68%
Future compensation assumption			2.36%	2.37%
Expected long-term return on plan assets			6.41%	6.45%
Postretirement
Benefit Obligation
Discount rate		3.42%	3.42%	4.34%
Benefit Cost
Discount rate	4.34%	3.94%		3.66%
Expected long-term return on plan assets			5.00%	5.00%
Minimum | Postretirement
Benefit Cost
Discount rate			4.34%
Maximum | Postretirement
Benefit Cost
Discount rate			3.94%

Retirement and Postretiremen_10

Retirement and Postretirement Benefits - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Curtailments		$ 8.9
Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost		17.4	$ 17.2	$ 18.2
Interest cost		48.9	45.6	49.1
Expected return on plan assets		(65)	(74)	(70.7)
Amortization of prior service cost		0.4	0.5	0.5
Curtailments		(8.9)	0	0
Net Periodic Benefit Cost (Income)		35.9	38.4	9.6
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement		43.1	49.1	12.5
Postretirement
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost		1.1	1.6	1.6
Interest cost		5.9	7.6	8.4
Expected return on plan assets		(3.9)	(4.8)	(5.2)
Amortization of prior service cost		(3.8)	0.2	1
Curtailments		0	0	0
Net Periodic Benefit Cost (Income)		5.7	(1)	15.1
Decrease in postretirement liability from plan amendment	$ 70.2
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement		$ 6.4	$ (5.6)	$ 9.3

Retirement and Postretiremen_11

Retirement and Postretirement Benefits - Allocation of Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019
Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	$ 1,054.4	$ 1,186.6	$ 1,155.4
Postretirement
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	86.1	$ 104	82.3
Level 1, 2 and 3 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	432		471.4
Level 1, 2 and 3 | Postretirement
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	14.5		18.8
Level 1 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	307.6		353.2
Level 1 | Postretirement
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	14.5		18.8
Level 2 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	124.4		118.2
Level 2 | Postretirement
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	0		0
Level 3 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	0		0
Level 3 | Postretirement
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	0		0
Assets measured at net asset value | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	$ 622.4		684
Redemption period	90 days	90 days
Assets measured at net asset value | Postretirement
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	$ 71.6		63.5
Redemption period	90 days	90 days
Cash and cash equivalents | Level 1, 2 and 3 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	$ 22.5		12.2
Cash and cash equivalents | Level 1, 2 and 3 | Postretirement
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	5.6		3
Cash and cash equivalents | Level 1 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	0.6		0.9
Cash and cash equivalents | Level 1 | Postretirement
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	5.6		3
Cash and cash equivalents | Level 2 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	21.9		11.3
Cash and cash equivalents | Level 2 | Postretirement
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	0		0
Cash and cash equivalents | Level 3 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	0		0
Cash and cash equivalents | Level 3 | Postretirement
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	0		0
U.S government and agency securities | Level 1, 2 and 3 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	234.2		250.3
U.S government and agency securities | Level 1 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	229.1		246.1
U.S government and agency securities | Level 2 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	5.1		4.2
U.S government and agency securities | Level 3 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	0		0
Corporate bonds | Level 1, 2 and 3 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	97.4		102.7
Corporate bonds | Level 1 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	0		0
Corporate bonds | Level 2 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	97.4		102.7
Corporate bonds | Level 3 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	0		0
Equity securities | Level 1, 2 and 3 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	37.1		49.8
Equity securities | Level 1 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	37.1		49.8
Equity securities | Level 2 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	0		0
Equity securities | Level 3 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	0		0
Mutual fund - fixed income | Level 1, 2 and 3 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	33.1		56.4
Mutual fund - fixed income | Level 1, 2 and 3 | Postretirement
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	8.9		15.8
Mutual fund - fixed income | Level 1 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	33.1		56.4
Mutual fund - fixed income | Level 1 | Postretirement
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	8.9		15.8
Mutual fund - fixed income | Level 2 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	0		0
Mutual fund - fixed income | Level 2 | Postretirement
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	0		0
Mutual fund - fixed income | Level 3 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	0		0
Mutual fund - fixed income | Level 3 | Postretirement
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	0		$ 0
Mutual fund - real estate | Level 1, 2 and 3 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	7.7
Mutual fund - real estate | Level 1 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	7.7
Mutual fund - real estate | Level 2 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	0
Mutual fund - real estate | Level 3 | Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total Assets	$ 0

Retirement and Postretiremen_12

Retirement and Postretirement Benefits - Benefit Payments (Details) $ in Millions	Dec. 31, 2018USD ($)
Pension
Benefit Payments
2019	$ 78.8
2020	79.2
2021	85.6
2022	76.5
2023	76
2024-2028	374.3
Postretirement
Benefit Payments
2019	11.9
2020	11
2021	10.3
2022	9.6
2023	9
2024-2028	$ 39.3

Stock-Based Compensation - Nar

Stock-Based Compensation - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)shares	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Apr. 28, 2016shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of options exercised	$ 0.1
Cash proceeds from options exercised	0.2	$ 0.2	$ 0.2
Tax benefit from option exercises	0
Stock Option Awards and Stock-Settled Restricted Share Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	7.4	7.3	$ 6.5
Unrecognized compensation cost	$ 7.3
Unrecognized compensation cost, period for recognition	1 year 4 months 24 days
Restricted Shares and Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Vesting increment	25.00%
Restricted Stock Units, Settled in Cash
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 0.1	0.8
Payments for cash-settled awards	$ 0.1	$ 0
TimkenSteel 2014 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares) | shares				11,050,000
Aggregate share limit ratio				2.50
Shares available for grant (in shares) | shares	2,400,000
Current Holders of Timken Equity Awards at Time of Spinoff | TimkenSteel 2014 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares) | shares				3,000,000

Stock-Based Compensation - Assu

Stock-Based Compensation - Assumptions Used in Calculating Fair Value of Options (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Weighted-average fair value per option (in USD per share)	$ 5.54	$ 7.46	$ 7.68
Risk-free interest rate	2.63%	2.77%	2.21%
Dividend yield	0.00%	0.00%	0.00%
Expected stock volatility	41.36%	41.67%	43.23%
Expected life - years	6 years	6 years	6 years

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Option Activity (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)$ / sharesshares
Number of Shares
Beginning balance (in shares) | shares	2,532,669
Granted (in shares) | shares	329,720
Exercised (in shares) | shares	(25,039)
Canceled, forfeited or expired (in shares) | shares	(195,780)
Ending balance (in shares) | shares	2,641,570
Weighted Average Exercise Price
Beginning balance (in USD per share) | $ / shares	$ 21.33
Granted (in USD per share | $ / shares	12.45
Exercised (in USD per share) | $ / shares	8.83
Canceled, forfeited or expired (in USD per share) | $ / shares	17.33
Ending balance (in USD per share) | $ / shares	$ 20.64
Additional Information
Outstanding, weighted average remaining contractual term	5 years 3 months 7 days
Outstanding, weighted average remaining contractual term | $	$ 0.2
Options expected to vest, number of shares (in shares) | shares	403,774
Options expected to vest, weighted average exercise price (in USD per share) | $ / shares	$ 13.43
Options expected to vest, weighted average remaining contractual term	8 years 3 months 18 days
Options expected to vest, aggregate intrinsic value | $	$ 0
Options exercisable, number of shares (in shares) | shares	2,237,796
Options exercisable, weighted average exercise price (in USD per share) | $ / shares	$ 21.94
Options exercisable, weighted average remaining contractual term	4 years 8 months 23 days
Options exercisable, aggregate intrinsic value | $	$ 0.2

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Share Activity (Details) - Stock Settled Restricted Stock	12 Months Ended
	Dec. 31, 2019$ / sharesshares
Number of Shares
Beginning balance (in shares) | shares	817,884
Granted (in shares) | shares	833,220
Vested (in shares) | shares	(365,800)
Canceled, forfeited or expired (in shares) | shares	(111,635)
Ending balance (in shares) | shares	1,173,669
Weighted Average Grant Date Fair Value
Beginning balance (in USD per share) | $ / shares	$ 11.94
Granted (in USD per share) | $ / shares	9.86
Vested (in USD per share) | $ / shares	10.23
Canceled, forfeited or expired (in USD per share) | $ / shares	13.79
Ending balance (in USD per share) | $ / shares	$ 14.15

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other comprehensive income before reclassifications, before income tax	$ 0.5	$ (1.9)
Amounts reclassified from accumulated other comprehensive loss, before income tax	(2.4)	0.7
Amounts deferred to accumulated other comprehensive income (loss), before income tax	72.2
Income tax	(16.7)	(0.1)
Net current period other comprehensive income, net of income taxes	53.6	(1.3)
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(7.3)	(5.9)
Other comprehensive income before reclassifications, before income tax	0.5	(1.4)
Amounts reclassified from accumulated other comprehensive loss, before income tax	0	0
Amounts deferred to accumulated other comprehensive income (loss), before income tax	0
Income tax	0	0
Net current period other comprehensive income, net of income taxes	0.5	(1.4)
Ending Balance	(6.8)	(7.3)
Pension and Postretirement Liability Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(1.6)	(1.7)
Other comprehensive income before reclassifications, before income tax	0	(0.5)
Amounts reclassified from accumulated other comprehensive loss, before income tax	(2.4)	0.7
Amounts deferred to accumulated other comprehensive income (loss), before income tax	72.2
Income tax	(16.7)	(0.1)
Net current period other comprehensive income, net of income taxes	53.1	0.1
Ending Balance	51.5	(1.6)
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(8.9)	(7.6)
Ending Balance	$ 44.7	$ (8.9)

Contingencies - Narrative (Deta

Contingencies - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Loss Contingency Accrual, Disclosures [Abstract]
Contingency reserves	$ 1.5	$ 1.5

Relationships with The Timken_2

Relationships with The Timken Company and Related Entities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Related Party Transactions [Abstract]
Related party sales of product	$ 26.1	$ 43.2	$ 48.5
Related party sales of product as a percent of sales	2.20%	2.70%	3.60%

Selected Quarterly Financial _3

Selected Quarterly Financial Data (Unaudited) - Schedule of Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales	$ 226.9	$ 274.2	$ 336.7	$ 371	$ 406.4	$ 409.9	$ 413.5	$ 380.8	$ 1,208.8	$ 1,610.6	$ 1,329.2
Gross Profit	(18)	(2.6)	14.8	28.4	37.3	28.4	38.5	22.4	22.6	126.6	80.3
Net Income (Loss)	$ (84.6)	$ (17)	$ (11.9)	$ 3.5	$ (29.4)	$ 5.2	$ 14.8	$ (0.6)	$ (110)	$ (10)	$ (31.3)
Per Share Data:
Basic earnings (loss) per share (in dollars per share)	$ (1.89)	$ (0.38)	$ (0.27)	$ 0.08	$ (0.66)	$ 0.12	$ 0.33	$ (0.01)	$ (2.46)	$ (0.22)	$ (0.70)
Diluted earnings (loss) per share (in dollars per share)	$ (1.89)	$ (0.38)	$ (0.27)	$ 0.08	$ (0.66)	$ 0.12	$ 0.33	$ (0.01)	$ (2.46)	$ (0.22)	$ (0.70)
As Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales		$ 274.2	$ 336.7	$ 371	$ 406.4	$ 409.9	$ 413.5	$ 380.8
Gross Profit		13.2	25.4	29.1	27.1	24.6	32.1	21.1
Net Income (Loss)		$ (4.6)	$ (4.4)	$ 4.2	$ (39.6)	$ 1.4	$ 8.4	$ (1.9)
Per Share Data:
Basic earnings (loss) per share (in dollars per share)		$ (0.10)	$ (0.10)	$ 0.09	$ (0.89)	$ 0.03	$ 0.19	$ (0.04)
Diluted earnings (loss) per share (in dollars per share)		$ (0.10)	$ (0.10)	$ 0.09	$ (0.89)	$ 0.03	$ 0.19	$ (0.04)
Adjustments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales		$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0
Gross Profit		(15.8)	(10.6)	(0.7)	10.2	3.8	6.4	1.3
Net Income (Loss)		$ (12.4)	$ (7.5)	$ (0.7)	$ 10.2	$ 3.8	$ 6.4	$ 1.3
Per Share Data:
Basic earnings (loss) per share (in dollars per share)		$ (0.28)	$ (0.17)	$ (0.01)	$ 0.23	$ 0.09	$ 0.14	$ 0.03
Diluted earnings (loss) per share (in dollars per share)		$ (0.28)	$ (0.17)	$ (0.01)	$ 0.23	$ 0.09	$ 0.14	$ 0.03