W.R. Grace & Co. (GRA) 10-Q 8 May 20 2020 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2020	Apr. 30, 2020
Document and Entity Information
Title of 12(b) Security	Common Stock, $0.01 par value per share
Entity Incorporation, State or Country Code	DE
Trading Symbol	GRA
Entity Registrant Name	W. R. GRACE & CO.
Entity Address, Address Line One	7500 Grace Drive
Entity Address, City or Town	Columbia
Entity Address, State or Province	MD
Entity Address, Postal Zip Code	21044-4098
City Area Code	(410)
Local Phone Number	531-4000
Entity Central Index Key	0001045309
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2020
Document Transition Report	false
Entity File Number	1-13953
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		66,172,136
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Entity Tax Identification Number	65-0773649
Security Exchange Name	NYSE

Consolidated Statements of Oper

Consolidated Statements of Operations (unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Revenues	$ 421.5	$ 469.5
Cost of goods sold	261.9	280.9
Gross profit	159.6	188.6
Selling, general and administrative expenses	71.1	73.2
Research and development expenses	17	17
Costs related to legacy matters	2.7	46.9
Equity in earnings of unconsolidated affiliate	(1.2)	(4.1)
Restructuring and repositioning expenses	2.7	2.3
Interest expense and related financing costs	18.3	20
Other (income) expense, net	(8.8)	(2.2)
Total costs and expenses	101.8	153.1
Income (loss) before income taxes	57.8	35.5
(Provision for) benefit from income taxes	(15.7)	(10.9)
Net income (loss)	42.1	24.6
Less: Net (income) loss attributable to noncontrolling interests	(0.1)	0.1
Net income (loss) attributable to W. R. Grace & Co. shareholders	$ 42	$ 24.7
Basic earnings per share:
Net income (loss) (in dollars per share)	$ 0.63	$ 0.37
Weighted average number of basic shares (in shares)	66.5	66.8
Diluted earnings per share:
Net income (loss) (in dollars per shares)	$ 0.63	$ 0.37
Weighted average number of diluted shares (in shares)	66.5	66.9
Dividends per common share (in dollars per shares)	$ 0.30	$ 0.27

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) (unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 42.1	$ 24.6
Other comprehensive income (loss), net of income taxes:
Defined benefit pension and other postretirement plans	(0.1)	(0.1)
Currency translation adjustments	2.5	11.7
Gain (loss) from hedging activities	(1)	(3)
Total other comprehensive income (loss)	1.4	8.6
Comprehensive income (loss)	43.5	33.2
Less: comprehensive (income) loss attributable to noncontrolling interests	(0.1)	0.1
Comprehensive income (loss) attributable to W. R. Grace & Co. shareholders	$ 43.4	$ 33.3

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
OPERATING ACTIVITIES
Net income (loss)	$ 42.1	$ 24.6
Reconciliation to net cash provided by (used for) operating activities:
Depreciation and amortization	25.5	24.9
Equity in earnings of unconsolidated affiliate	(1.2)	(4.1)
Costs related to legacy matters	2.7	46.9
Cash paid for legacy matters	7.6	3.2
Provision for (benefit from) income taxes	15.7	10.9
Cash paid for income taxes	(14.4)	(10.9)
Income tax refunds received	0.8	0.8
Interest expense and related financing costs	18.3	20
Defined benefit pension expense	3.1	4.8
Cash paid under defined benefit pension arrangements	(4.4)	(4)
Changes in assets and liabilities, excluding effect of currency translation and acquisitions:
Trade accounts receivable	47.3	26.6
Inventories	(31.7)	(35.5)
Accounts payable	(3.8)	3.5
All other items, net	(19.5)	(14.3)
Net cash provided by (used for) operating activities	54.6	71
INVESTING ACTIVITIES
Cash paid for capital expenditures	(57.1)	(38.2)
Other investing activities, net	(16.6)	(7.9)
Net cash provided by (used for) investing activities	(73.7)	(46.1)
FINANCING ACTIVITIES
Borrowings under credit arrangements	4.2	2.2
Repayments under credit arrangements	(6.1)	(5.7)
Cash paid for repurchases of common stock	(40.4)	(4.8)
Proceeds from exercise of stock options	0	9.2
Dividends paid to shareholders	(20.5)	(18.4)
Other financing activities, net	(4.2)	(4.3)
Net cash provided by (used for) financing activities	(67)	(21.8)
Effect of currency exchange rate changes on cash, cash equivalents, and restricted cash	(3.1)	(0.3)
Net increase (decrease) in cash, cash equivalents, and restricted cash	(89.2)	2.8
Cash, cash equivalents, and restricted cash, beginning of period	282.9	201
Cash, cash equivalents, and restricted cash, end of period	193.7	203.8
Supplemental disclosure of cash flow information
Interest Paid, Excluding Capitalized Interest, Operating Activities	4	5.3
Capital expenditures in accounts payable	29.7	44.3
Expenditures for other investing activities included in accounts payable	$ 10.4	$ 13.5

Consolidated Balance Sheets (un

Consolidated Balance Sheets (unaudited) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Current Assets
Cash and cash equivalents	$ 193.2	$ 282.5
Restricted cash and cash equivalents	0.5	0.4
Trade accounts receivable, less allowance of $13.5 (2019—$13.3)	258.3	307
Inventories	339.1	309.9
Other current assets	245.1	235.1
Total Current Assets	1,036.2	1,134.9
Properties and equipment, net of accumulated depreciation and amortization of $1,503.2 (2019—$1,497.0)	1,153.2	1,143.8
Goodwill	556.2	556.9
Technology and other intangible assets, net	337.3	342.8
Deferred income taxes	511.7	517.6
Investment in unconsolidated affiliate	182.6	181.9
Other assets	66.8	54.7
Total Assets	3,844	3,932.6
Current Liabilities
Debt payable within one year	23.5	23.1
Accounts payable	258.6	302.3
Other current liabilities	414.6	419.7
Total Current Liabilities	696.7	745.1
Debt payable after one year	1,954.8	1,957.3
Defined Benefit Pension Plan Liabilities Noncurrent Unfunded	430.3	434.6
Defined Benefit Pension Plan Liabilities Noncurrent Underfunded	84.5	85.2
Other liabilities	293.8	308.2
Total Liabilities	3,460.1	3,530.4
Commitments and Contingencies—Note 8
Equity
Common stock issued, par value $0.01; 300,000,000 shares authorized; outstanding: 66,172,030 (2019—66,735,913)	0.7	0.7
Paid-in capital	466.4	477.9
Retained earnings	752.3	730.5
Treasury stock, at cost: shares: 11,284,603 (2019—10,720,720)	(922.3)	(892.2)
Accumulated other comprehensive income (loss)	80.2	78.8
Total W. R. Grace & Co. Shareholders’ Equity	377.3	395.7
Noncontrolling interests	6.6	6.5
Total Equity	383.9	402.2
Total Liabilities and Equity	$ 3,844	$ 3,932.6

Consolidated Balance Sheets (_2

Consolidated Balance Sheets (unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 13.5	$ 13.3
Accumulated depreciation	$ 1,503.2	$ 1,497
Common stock issued, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock issued, shares authorized (in shares)	300,000,000	300,000,000
Common stock issued, shares outstanding (in shares)	66,172,030	66,735,913
Treasury stock, at cost (shares)	11,284,603	10,720,720

Consolidated Statements of Equi

Consolidated Statements of Equity (unaudited) - USD ($) $ in Millions	Total	Common Stock and Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests
Beginning balance at Dec. 31, 2018	$ 337	$ 481.8	$ 676.7	$ (895.5)	$ 67.9	$ 6.1
Increase (Decrease) in Stockholders' Equity
Net income	24.6	0	24.7	0	0	(0.1)
Repurchase of common stock	(4.8)	0	0	(4.8)	0	0
Cash paid for repurchases of common stock	4.8
Payments in consideration of employee tax obligations related to stock-based compensation	(4.3)	(4.3)	0	0	0	0
Stock-based compensation	1.9	1.9	0	0	0	0
Exercise of stock options	9.2	(2.2)	0	11.4	0	0
Shares issued	(0.3)	(7.4)	0	7.1	0	0
Dividends declared	(18.1)	0	(18.1)	0	0	0
Other comprehensive (loss) income	8.6	0	0	0	8.6	0
Ending balance at Mar. 31, 2019	353.8	469.8	683.3	(881.8)	76.5	6
Beginning balance at Dec. 31, 2019	402.2	478.6	730.5	(892.2)	78.8	6.5
Increase (Decrease) in Stockholders' Equity
Net income	42.1	0	42	0	0	0.1
Repurchase of common stock	(40.4)	0	0	(40.4)	0	0
Cash paid for repurchases of common stock	40.4
Payments in consideration of employee tax obligations related to stock-based compensation	(4.1)	(4.1)	0	0	0	0
Stock-based compensation	2.9	2.9	0	0	0	0
Shares issued	0	(10.3)	0	10.3	0	0
Dividends declared	(20.2)	0	(20.2)	0	0	0
Other comprehensive (loss) income	1.4	0	0	0	1.4	0
Ending balance at Mar. 31, 2020	$ 383.9	$ 467.1	$ 752.3	$ (922.3)	$ 80.2	$ 6.6

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting and Financial Reporting Policies	3 Months Ended
	Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Summary of Significant Accounting and Financial Reporting Policies	W. R. Grace & Co., through its subsidiaries, is engaged in the production and sale of specialty chemicals and specialty materials on a global basis through two reportable business segments: Grace Catalysts Technologies, which includes catalysts and related products and technologies used in petrochemical, refining, and other chemical manufacturing applications; and Grace Materials Technologies, which includes specialty materials, including silica-based and silica-alumina-based materials, used in consumer/pharma, coatings, and chemical process applications. W. R. Grace & Co. conducts all of its business through a single wholly owned subsidiary, W. R. Grace & Co.–Conn. (“Grace–Conn.”). Grace–Conn. owns all of the assets, properties and rights of W. R. Grace & Co. on a consolidated basis, either directly or through subsidiaries. Basis of Presentation The interim Consolidated Financial Statements presented herein are unaudited and should be read in conjunction with the Consolidated Financial Statements presented in the Company’s 2019 Annual Report on Form 10-K. Such interim Consolidated Financial Statements reflect all adjustments that, in the opinion of management, are necessary for a fair statement of the results of the interim periods presented; all such adjustments are of a normal recurring nature except for the impacts of adopting new accounting standards as discussed below. All significant intercompany accounts and transactions have been eliminated. The results of operations for the three-month interim period ended March 31, 2020 , are not necessarily indicative of the results of operations to be attained for the year ending December 31, 2020 . Use of Estimates The preparation of financial statements in conformity with U.S. generally accepted accounting principles (“U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the Consolidated Financial Statements, and the reported amounts of revenues and expenses for the periods presented. Actual amounts could differ from those estimates, and the differences could be material. Changes in estimates are recorded in the period identified. Grace’s accounting measurements that are most affected by management’s estimates of future events are: • The effective tax rate and realization values of net deferred tax assets, which depend on projections of future taxable income; • Pension and postretirement liabilities, which depend on assumptions regarding participant life spans, future inflation, discount rates and total returns on invested funds (see Note 6); • Carrying values of goodwill and other intangible assets, which depend on assumptions of future earnings and cash flows; and • Contingent liabilities, which depend on an assessment of the probability of loss and an estimate of ultimate obligation, such as litigation, environmental remediation, and other legacy liabilities (see Note 8). Reclassifications Certain amounts in prior years’ Consolidated Financial Statements have been reclassified to conform to the current year presentation. Such reclassifications have not materially affected previously reported amounts in the Consolidated Financial Statements. Recently Issued Accounting Standards In December 2019, the FASB issued ASU 2019-12 “Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes.” This update clarifies and amends existing guidance, including removing certain exceptions to the general principles in Topic 740, and improves consistent application of and simplifies U.S. GAAP for other areas of Topic 740. This update is effective for Grace on January 1, 2021, with early adoption permitted. Grace is currently evaluating the effect and timing of adoption. Recently Adopted Accounting Standards In March 2020, the FASB issued ASU 2020-04 “Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting.” This update is intended to ease the potential burden in accounting for and recognizing the effects of reference rate reform. It provides optional practical expedients and exceptions for applying U.S. GAAP to contracts, hedging relationships, and other transactions affected by reference rate reform, if certain criteria are met. This update became effective on March 12, 2020, and is available for use through December 31, 2022. Grace expects to utilize the practical expedients provided by this update in accounting for contract modifications and/or hedging transactions during the effective period. Grace expects the update to significantly reduce the effects of reference rate reform on the Consolidated Financial Statements. In August 2018, the FASB issued ASU 2018-14 “Compensation—Retirement Benefits—Defined Benefit Plans—General (Subtopic 715-20).” This update revises disclosure requirements related to defined benefit pension and other postretirement plans. Grace adopted this update in the 2020 first quarter, and it did not have a material effect on the Consolidated Financial Statements. In June 2016, the FASB issued ASU 2016-13 “Financial Instruments—Credit Losses (Topic 326) Measurement of Credit Losses on Financial Instruments.” This update requires companies to implement an impairment model based on expected credit losses, rather than probable incurred losses. Grace adopted this update in the 2020 first quarter, and it did not have a material effect on the Consolidated Financial Statements.

Inventories

Inventories	3 Months Ended
	Mar. 31, 2020
Inventory Disclosure [Abstract]
Inventories	Inventories are stated at the lower of cost or net realizable value, and cost is determined using FIFO. Inventories consisted of the following at March 31, 2020 , and December 31, 2019 : (In millions) March 31, December 31, Raw materials $ 64.8 $ 64.2 In process 60.8 55.7 Finished products 177.6 154.4 Other 35.9 35.6 Total inventory $ 339.1 $ 309.9

Debt

Debt	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Debt	Components of Debt (In millions) March 31, December 31, 2018 U.S. dollar term loan, net of unamortized debt issuance costs of $6.9 (2019—$7.2) $ 928.8 $ 930.9 Senior notes due 2021, net of unamortized debt issuance costs of $2.3 (2019—$2.7) 697.7 697.3 Senior notes due 2024, net of unamortized debt issuance costs of $2.3 (2019—$2.4) 297.7 297.6 Debt payable to unconsolidated affiliate 47.0 47.4 Other borrowings 7.1 7.2 Total debt 1,978.3 1,980.4 Less debt payable within one year 23.5 23.1 Debt payable after one year $ 1,954.8 $ 1,957.3 Weighted average interest rates on total debt 3.7 % 3.8 % See Note 4 for a discussion of the fair value of Grace’s debt. Grace also maintains a $400 million revolving credit facility. As of March 31, 2020 , the available credit under this facility was reduced to $381.3 million by outstanding letters of credit. The principal maturities of debt outstanding at March 31, 2020 , were as follows: (In millions) 2020 $ 18.6 2021 717.3 2022 18.7 2023 17.8 2024 313.3 Thereafter 892.6 Total debt $ 1,978.3

Fair Value Measurements and Ris

Fair Value Measurements and Risk	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements and Risk	Certain of Grace’s assets and liabilities are reported at fair value on a gross basis. ASC 820 “Fair Value Measurements and Disclosures” defines fair value as the value that would be received at the measurement date in the principal or “most advantageous” market. Grace uses principal market data, whenever available, to value assets and liabilities that are required to be reported at fair value. Grace has identified the following financial assets and liabilities that are subject to the fair value analysis required by ASC 820: Fair Value of Debt and Other Financial Instruments Debt payable is recorded at carrying value. Fair value is determined based on Level 2 inputs, including expected future cash flows (discounted at market interest rates), estimated current market prices and quotes from financial institutions. At March 31, 2020 , and December 31, 2019 , the carrying amounts and fair values of Grace’s debt were as follows: March 31, 2020 December 31, 2019 (In millions) Carrying Amount Fair Value Carrying Amount Fair Value 2018 U.S. dollar term loan(1) $ 928.8 $ 789.5 $ 930.9 $ 938.1 Senior notes due 2021(2) 697.7 706.0 697.3 727.1 Senior notes due 2024(2) 297.7 297.7 297.6 329.2 Other borrowings 54.1 54.1 54.6 54.6 Total debt $ 1,978.3 $ 1,847.3 $ 1,980.4 $ 2,049.0 ___________________________________________________________________________________________________________________ (1) Carrying amounts are net of unamortized debt issuance costs and discounts of $6.9 million and $7.2 million as of March 31, 2020 , and December 31, 2019 , respectively. (2) Carrying amounts are net of unamortized debt issuance costs of $2.3 million and $2.3 million as of March 31, 2020 , and $2.7 million and $2.4 million as of December 31, 2019 , related to the senior notes due 2021 and senior notes due 2024, respectively. At March 31, 2020 , the recorded values of other financial instruments such as cash equivalents and trade receivables and payables approximated their fair values, based on the short-term maturities and floating rate characteristics of these instruments. Currency Derivatives Because Grace operates and/or sells to customers in over 60 countries and in over 30 currencies, its results are exposed to fluctuations in currency exchange rates. Grace seeks to minimize exposure to these fluctuations by matching sales with expenditures in the same currencies, but it is not always possible to do so. From time to time, Grace uses financial instruments such as currency forward contracts, options, swaps, or combinations thereof to reduce the risk of certain specific transactions. However, Grace does not have a policy of hedging all exposures, because management does not believe that such a level of hedging would be cost-effective. Forward contracts with maturities of not more than 36 months are used and designated as cash flow hedges of forecasted repayments of intercompany loans. The effective portion of gains and losses on these currency hedges is recorded in “accumulated other comprehensive income (loss)” and reclassified into “other (income) expense, net” to offset the remeasurement of the underlying hedged loans. Forward points are excluded from the assessment of effectiveness and amortized to income on a systematic basis. Grace also enters into foreign currency forward contracts and swaps to hedge a portion of its net outstanding monetary assets and liabilities. These forward contracts and swaps are not designated as hedging instruments under applicable accounting guidance, and therefore all changes in their fair value are recorded in “other (income) expense, net,” in the Consolidated Statements of Operations. These forward contracts and swaps are intended to offset the foreign currency gains or losses associated with the underlying monetary assets and liabilities. The valuation of Grace’s currency exchange rate forward contracts and swaps is determined using an income approach. Inputs used to value currency exchange rate forward contracts and swaps consist of: (1) spot rates, which are quoted by various financial institutions; (2) forward points, which are primarily affected by changes in interest rates; and (3) discount rates used to present value future cash flows, which are based on the London Interbank Offered Rate (LIBOR) curve or overnight indexed swap rates. Total notional amounts for forward contracts and swaps outstanding as of March 31, 2020 , were $155.5 million . Cross-Currency Swap Agreements Grace uses cross-currency swaps designated as cash flow hedges to manage fluctuations in currency exchange rates and interest rates on variable rate debt. Gains and losses on these cash flow hedges are recorded in “accumulated other comprehensive income (loss)” and reclassified into “other (income) expense, net” and “interest expense and related financing costs” during the hedged period. In connection with the 2018 U.S. dollar term loan, Grace entered into cross-currency swaps beginning on November 5, 2018, and maturing on March 31, 2023, to synthetically convert $600.0 million of U.S. dollar-denominated floating rate debt into €525.9 million of euro-denominated debt fixed at 1.785% . The valuation of these cross-currency swaps is determined using an income approach, using LIBOR and EURIBOR (Euro Interbank Offered Rate) swap curves, currency basis spreads, and euro/U.S. dollar exchange rates. Debt and Interest Rate Swap Agreements Grace uses interest rate swaps designated as cash flow hedges to manage fluctuations in interest rates on variable rate debt. The effective portion of gains and losses on these interest rate cash flow hedges is recorded in “accumulated other comprehensive income (loss)” and reclassified into “interest expense and related financing costs” during the hedged interest period. In connection with the 2018 U.S. dollar term loan, Grace entered into interest rate swaps beginning on April 3, 2018, and maturing on March 31, 2023, fixing the LIBOR component of the interest on $100.0 million of term debt at 2.775% . The valuation of these interest rate swaps is determined using an income approach, using prevailing market interest rates and discount rates to present value future cash flows based on the forward LIBOR yield curves. Credit risk is also incorporated into derivative valuations. The following tables present the fair value hierarchy for financial assets and liabilities measured at fair value on a recurring basis as of March 31, 2020 , and December 31, 2019 : Fair Value Measurements at March 31, 2020, Using (In millions) Total Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Currency derivatives $ 14.6 $ — $ 14.6 $ — Variable-to-fixed cross-currency swaps 11.5 — 11.5 — Total Assets $ 26.1 $ — $ 26.1 $ — Liabilities Currency derivatives $ 1.2 $ — $ 1.2 $ — Interest rate derivatives 6.3 — 6.3 — Total Liabilities $ 7.5 $ — $ 7.5 $ — Fair Value Measurements at December 31, 2019, Using (In millions) Total Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Currency derivatives $ 6.1 $ — $ 6.1 $ — Variable-to-fixed cross-currency derivatives 3.4 — 3.4 — Total Assets $ 9.5 $ — $ 9.5 $ — Liabilities Currency derivatives $ 0.9 $ — $ 0.9 $ — Interest rate derivatives 3.4 — 3.4 — Total Liabilities $ 4.3 $ — $ 4.3 $ — The following tables present the location and fair values of derivative instruments included in the Consolidated Balance Sheets as of March 31, 2020 , and December 31, 2019 : March 31, 2020 Asset Derivatives Liability Derivatives Balance Sheet Location Fair Value Balance Sheet Location Fair Value Derivatives designated as hedging instruments under ASC 815: Currency contracts Other current assets $ 6.2 Other current liabilities $ — Currency contracts Other assets 8.4 Other liabilities — Interest rate contracts Other current assets — Other current liabilities 2.1 Interest rate contracts Other assets — Other liabilities 4.2 Variable-to-fixed cross-currency swaps Other current assets 4.2 Other current liabilities — Variable-to-fixed cross-currency swaps Other assets 7.3 Other liabilities — Derivatives not designated as hedging instruments under ASC 815: Currency contracts Other current assets — Other current assets (0.5 ) Currency contracts Other current assets — Other current liabilities 1.7 Total derivatives $ 26.1 $ 7.5 December 31, 2019 Asset Derivatives Liability Derivatives Balance Sheet Location Fair Value Balance Sheet Location Fair Value Derivatives designated as hedging instruments under ASC 815: Currency contracts Other current assets $ 2.1 Other current assets $ (3.1 ) Currency contracts Other assets 4.0 Other liabilities 4.0 Interest rate contracts Other current assets — Other current liabilities 1.0 Interest rate contracts Other assets — Other liabilities 2.4 Variable-to-fixed cross-currency swaps Other current assets 10.2 Other current liabilities — Variable-to-fixed cross-currency swaps Other liabilities (6.8 ) Other liabilities — Derivatives not designated as hedging instruments under ASC 815: Currency contracts Other current assets — Other current assets (0.2 ) Currency contracts Other current assets — Other current liabilities 0.2 Total derivatives $ 9.5 $ 4.3 The following tables present the location and amount of gains and losses on derivative instruments included in the Consolidated Statements of Operations or, when applicable, gains and losses initially recognized in other comprehensive income (loss) (“OCI”) for the three months ended March 31, 2020 and 2019 : Three Months Ended March 31, 2020 Amount of Gain (Loss) Recognized in OCI on Derivatives Location of Gain (Loss) Reclassified from Accumulated OCI into Income Amount of Gain (Loss) Reclassified from OCI into Income Derivatives in ASC 815 cash flow hedging relationships: Interest rate contracts $ (3.1 ) Interest expense $ (0.2 ) Currency contracts(1) 2.4 Other expense 1.4 Variable-to-fixed cross-currency swaps 3.4 Interest expense 2.5 Variable-to-fixed cross-currency swaps 7.6 Other expense 7.6 Total derivatives $ 10.3 $ 11.3 Location of Gain (Loss) Recognized in Income on Derivatives Amount of Gain (Loss) Recognized in Income on Derivatives Derivatives not designated as hedging instruments under ASC 815: Currency contracts Other expense $ (1.9 ) ___________________________________________________________________________________________________________________ (1) Amount of gain (loss) recognized in OCI includes $1.1 million excluded from the assessment of effectiveness for which the difference between changes in fair value and periodic amortization is recorded in OCI. Three Months Ended March 31, 2019 Amount of Gain (Loss) Recognized in OCI on Derivatives Location of Gain (Loss) Reclassified from Accumulated OCI into Income Amount of Gain (Loss) Reclassified from OCI into Income Derivatives in ASC 815 cash flow hedging relationships: Interest rate contracts $ (1.1 ) Interest expense $ — Currency contracts(1) 1.6 Other expense 1.3 Variable-to-fixed cross-currency swaps 0.1 Interest expense 3.6 Variable-to-fixed cross-currency swaps 8.4 Other expense 8.4 Total derivatives $ 9.0 $ 13.3 Location of Gain (Loss) Recognized in Income on Derivatives Amount of Gain (Loss) Recognized in Income on Derivatives Derivatives not designated as hedging instruments under ASC 815: Currency contracts Other expense $ (0.1 ) ___________________________________________________________________________________________________________________ (1) Amount of gain (loss) recognized in OCI includes $0.0 million excluded from the assessment of effectiveness for which the difference between changes in fair value and periodic amortization is recorded in OCI. The following table presents the total amounts of income and expense line items presented in the Consolidated Statements of Operations in which the effects of cash flow hedges are reported. Three Months Ended March 31, 2020 2019 (In millions) Interest expense Other income (expense) Interest expense Other income (expense) Total amounts of income and expense line items in the Consolidated Statements of Operations in which the effects of cash flow hedges are recorded $ (18.3 ) $ 8.8 $ (20.0 ) $ 2.2 Gain (loss) on cash flow hedging relationships in ASC 815 Interest rate contracts Gain (loss) reclassified from accumulated OCI into income $ (0.2 ) $ — $ — $ — Variable-to-fixed cross-currency swaps Gain (loss) reclassified from accumulated OCI into income 2.5 7.6 3.6 8.4 Currency contracts Gain (loss) reclassified from accumulated OCI into income — 1.4 — 1.3 Amount excluded from effectiveness testing recognized in earnings based on amortization approach (included in above) — 0.7 — 0.7 Net Investment Hedges Grace uses cross-currency swaps as derivative hedging instruments in certain net investment hedges of its non-U.S. subsidiaries. The gains and losses attributable to these net investment hedges, adjusted for the impact of excluded components, are recorded net of tax to “currency translation adjustments” within “accumulated other comprehensive income (loss)” to offset the change in the carrying value of the net investment being hedged. Recognition in earnings of amounts previously recorded to “currency translation adjustments” is limited to circumstances such as complete or substantially complete liquidation of the net investment in the hedged foreign operation. Changes in the fair value of the hedging instrument related to time value, which are excluded from the assessment of hedge effectiveness, are recorded directly to interest expense on a systematic basis. These gains were $0.9 million and $0.8 million for the three months ended March 31, 2020 and 2019 , respectively. At March 31, 2020 , the notional amount of €170.0 million of Grace’s cross-currency swaps was designated as a hedging instrument of its net investment in its European subsidiaries. The following table presents the amount of gains and losses on derivative instruments designated as net investment hedges, recorded to “currency translation adjustments” within “accumulated other comprehensive income (loss)” for the three months ended March 31, 2020 and 2019 . There were no reclassifications of the effective portion of net investment hedges out of OCI and into earnings for the periods presented. Three Months Ended March 31, (In millions) 2020 2019 Derivatives in ASC 815 net investment hedging relationships: Cross-currency swap $ 6.1 $ 3.8 Credit Risk Grace is exposed to credit risk in its trade accounts receivable. Grace’s credit evaluation policies mitigate credit risk exposures, and it has a history of minimal credit losses. Grace does not generally require collateral for its trade accounts receivable, but may require a bank letter of credit in certain instances, particularly when selling to customers in cash-restricted countries. Grace may also be exposed to credit risk in its derivatives contracts. Grace monitors counterparty credit risk and currently does not anticipate nonperformance by counterparties to its derivatives. Grace’s derivative contracts are with internationally recognized commercial financial institutions.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Grace’s effective tax rates for the three months ended March 31, 2020 and 2019 , were 27.2% and 30.7% , respectively. For both periods, Grace’s effective tax rate was higher than the U.S. federal statutory rate primarily due to income taxed in jurisdictions with higher statutory tax rates than the U.S. As of March 31, 2020 , Grace had $302.0 million in federal tax credit carryforwards before unrecognized tax benefits.

Pension Plans and Other Postret

Pension Plans and Other Postretirement Benefit Plans	3 Months Ended
	Mar. 31, 2020
Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]
Pension Plans and Other Postretirement Benefit Plans	Pension Plans The following table presents the funded status of Grace’s pension plans: (In millions) March 31, December 31, Overfunded defined benefit pension plans $ 8.9 $ 8.5 Underfunded defined benefit pension plans (84.5 ) (85.2 ) Unfunded defined benefit pension plans (430.3 ) (434.6 ) Total underfunded and unfunded defined benefit pension plans (514.8 ) (519.8 ) Pension liabilities included in other current liabilities (14.7 ) (14.8 ) Net funded status $ (520.6 ) $ (526.1 ) Fully-funded plans include several advance-funded plans where the fair value of the plan assets exceeds the projected benefit obligation (“PBO”). Underfunded plans include a group of advance-funded plans that are underfunded on a PBO basis. Unfunded plans include several plans that are funded on a pay-as-you-go basis, and therefore, the entire PBO is unfunded. The following table presents the components of net periodic benefit cost (income). Three Months Ended March 31, 2020 2019 (In millions) U.S. Non-U.S. U.S. Non-U.S. Service cost $ 4.7 $ 2.7 $ 3.9 $ 2.2 Interest cost 7.6 1.0 9.6 1.3 Expected return on plan assets (12.0 ) (0.3 ) (12.0 ) (0.2 ) Amortization of prior service credit (0.2 ) — (0.2 ) — Net periodic benefit cost (income) $ 0.1 $ 3.4 $ 1.3 $ 3.3 Plan Contributions and Funding Grace intends to satisfy its funding obligations under the U.S. qualified pension plans and to comply with all of the requirements of the Employee Retirement Income Security Act of 1974 (“ERISA”). For ERISA purposes, funded status is calculated on a different basis than under U.S. GAAP. Grace intends to fund non-U.S. pension plans based on applicable legal requirements and actuarial recommendations. Defined Contribution Retirement Plans Grace sponsors a defined contribution retirement plan for its employees in the United States. This plan is qualified under section 401(k) of the U.S. tax code. Currently, Grace contributes an amount equal to 100% of employee contributions, up to 6% of an individual employee’s salary or wages. Grace’s cost related to this benefit plan for the three months ended March 31, 2020 and 2019 , was $3.3 million . U.S. salaried employees and certain U.S. hourly employees hired on or after January 1, 2017, and employees in Germany hired on or after January 1, 2016, participate in enhanced defined contribution plans instead of defined benefit pension plans. For the U.S. plan, Grace contributes 4% of an individual employee’s salary or wages. For the German plan, contributions vary based on the individual employee’s contributions and other factors. Grace’s cost related to these enhanced defined contribution plans established in the United States and Germany for the three months ended March 31, 2020 , was $1.2 million compared with $0.8 million for the prior-year quarter .

Other Balance Sheet Accounts

Other Balance Sheet Accounts	3 Months Ended
	Mar. 31, 2020
Other Balance Sheet Accounts [Abstract]
Other Balance Sheet Accounts	(In millions) March 31, December 31, Other Current Assets Plant under construction—unconsolidated affiliate (see Note 15) $ 184.7 $ 173.9 Non-trade accounts receivable 21.6 24.1 Fair value of currency, interest rate, and commodity contracts (see Note 4) 10.9 15.6 Income taxes receivable 9.5 4.2 Other current assets 18.4 17.3 $ 245.1 $ 235.1 (In millions) March 31, December 31, Other Current Liabilities Liability to unconsolidated affiliate for plant under construction (see Note 15) $ 184.7 $ 173.9 Accrued compensation 35.3 53.6 Deferred revenue (see Note 13) 34.8 35.0 Accrued interest (see Note 3) 26.4 13.3 Environmental contingencies (see Note 8) 18.7 17.8 Pension liabilities (see Note 6) 14.7 14.8 Income taxes payable (see Note 5) 11.5 8.6 Operating lease liabilities 8.9 9.3 Liability for dam spillway replacement (see Note 8) 4.4 4.7 Other accrued liabilities 75.2 88.7 $ 414.6 $ 419.7 Accrued compensation includes salaries and wages as well as estimated current amounts due under the annual and long-term incentive programs. (In millions) March 31, December 31, Other Liabilities Environmental contingencies (see Note 8) $ 94.1 $ 97.5 Liability for dam spillway replacement (see Note 8) 61.0 61.7 Deferred revenue (see Note 13) 30.0 29.5 Operating lease liabilities 25.4 26.2 Legacy product liability (see Note 8) 24.0 24.0 Retained obligations of divested businesses 11.9 12.7 Asset retirement obligation 9.5 9.4 Deferred income taxes 7.5 7.5 Fair value of currency and interest rate contracts (see Note 4) 4.2 13.2 Unrecognized tax benefits 4.0 4.1 Other noncurrent liabilities 22.2 22.4 $ 293.8 $ 308.2

Commitments and Contingent Liab

Commitments and Contingent Liabilities	3 Months Ended
	Mar. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities	Legacy Matters Over the years, Grace operated numerous types of businesses that are no longer part of its ongoing operations. As Grace divested or otherwise ceased operating these businesses, it retained certain liabilities and obligations, which Grace refers to as legacy liabilities. These liabilities include product, environmental and other liabilities. Although the outcome of each of the matters discussed below cannot be predicted with certainty, Grace has assessed its risk and has recorded estimated liabilities as required under U.S. GAAP. Legacy Product Liabilities Grace emerged from an asbestos-related Chapter 11 bankruptcy on February 3, 2014 (the “Effective Date”). Under its plan of reorganization, all pending and future asbestos-related claims are channeled for resolution to either a personal injury trust (the “PI Trust”) or a property damage trust (the “PD Trust”). The trusts are the sole recourse for holders of asbestos-related claims. The channeling injunctions issued by the bankruptcy court prohibit holders of asbestos-related claims from asserting such claims directly against Grace. Grace has satisfied all of its financial obligations to the PI Trust. Grace has contingent financial obligations remaining to the PD Trust. With respect to property damage claims related to Grace’s former Zonolite attic insulation product (“ZAI PD Claims”), the PD Trust was funded with $49.4 million (net of $15 million of attorneys’ fees) to pay claims and expenses. Grace is also obligated to make up to 10 contingent deferred payments of $8 million per year to the PD Trust during the 20 -year period beginning on the fifth anniversary of the Effective Date, with each such payment due only if the assets of the PD Trust in respect of ZAI PD Claims fall below $10 million during the preceding year. As of March 31, 2020 , the PD Trust has paid out approximately $32 million in ZAI PD Claims and expenses, leaving a balance of approximately $20 million , including the benefit of net investment gains. Due to the limited claims history, the unique nature of this product, and the uncertainty of future claims patterns, an actuarial analysis was completed to estimate the range of possible future payments. The analysis was conducted by a third-party actuarial firm directed by Grace and using historical claims data provided by the ZAI trustee. Certain key assumptions employed in the analysis were (1) projections of the future number of filed claims, assuming a percentage increase in claims during earlier years and annual decreases in later years; (2) application of historical percentages of claims closed with indemnity payment compared to total closed claims, applied on a regional basis; and (3) application of the average claim payout, which reflects the average indemnity cost per claim closing with payment. As a result of the analysis and taking into account the relative uncertainty of future claims activity, Grace determined that contingent funding obligations beyond the next five years are not reasonably estimable. Grace estimates that the reasonable range of payments over the next five years is expected to be between $16 million and $24 million and projects that the first payment could be due in 2022. In the 2019 fourth quarter, Grace recorded a reserve in the amount of $24.0 million related to probable future obligations to fund the PD Trust for ZAI PD Claims. Grace’s maximum financial obligation over the next 19 years is $80.0 million , and no single year’s obligation can exceed $8.0 million . With respect to other asbestos property damage claims (“Other PD Claims”), claims unresolved as of the Effective Date are to be litigated in the bankruptcy court and any future claims are to be litigated in a federal district court, in each case pursuant to procedures approved by the bankruptcy court. To the extent any such Other PD Claims are determined to be allowed claims, they are to be paid in cash by the PD Trust. Grace is obligated to make a payment to the PD Trust every six months in the amount of any Other PD Claims allowed during the preceding six months plus interest (if applicable) and the amount of PD Trust expenses for the preceding six months (the “PD Obligation”). Grace has not paid any Other PD Claims since emergence. Annual expenses have been approximately $0.2 million per year. The aggregate amount to be paid under the PD Obligation is not capped, and Grace may be obligated to make additional payments to the PD Trust in respect of the PD Obligation. Grace has accrued for those unresolved Other PD Claims that it believes are probable and estimable. Grace has not accrued for other unresolved or unasserted Other PD Claims as it does not believe that payment is probable. All payments to the PD Trust required after the Effective Date are secured by the Company’s obligation to issue 77,372,257 shares of Company common stock to the PD Trust in the event of default, subject to customary anti-dilution provisions. This summary of the commitments and contingencies related to the Chapter 11 proceeding does not purport to be complete and is qualified in its entirety by reference to the plan of reorganization and the exhibits and documents related thereto, which have been filed with the Securities and Exchange Commission (the “SEC”) and are readily available on the internet at www.sec.gov. Legacy Environmental Liabilities Grace is subject to loss contingencies resulting from extensive and evolving federal, state, local and foreign environmental laws and regulations relating to its manufacturing operations. Grace has procedures in place to minimize such contingencies; nevertheless, it has liabilities associated with past operations and additional claims may arise in the future, which may be material. To address its legacy liabilities, Grace accrues for anticipated costs of response efforts where an assessment has indicated that a probable liability has been incurred and the cost can be reasonably estimated. These accruals do not take into account any discounting for the time value of money. Grace’s environmental liabilities are reassessed regularly and adjusted when circumstances become better defined or response efforts and their costs can be better estimated, typically as a matter moves through the life-cycle of environmental investigation and remediation. These liabilities are evaluated based on currently available information relating to the nature and extent of contamination, risk assessments, feasibility of response actions, and apportionment amongst other potentially responsible parties, all evaluated in light of prior experience. At March 31, 2020 , Grace’s estimated liability for legacy environmental response costs totaled $112.8 million , compared with $115.3 million at December 31, 2019 , and was included in “other current liabilities” and “other liabilities” in the Consolidated Balance Sheets. These amounts are based on agreements in place or on Grace’s estimate of costs where no formal remediation plan exists, yet there is sufficient information to estimate response costs. Vermiculite-Related Matters Grace purchased a vermiculite mine in Libby, Montana, in 1963 and operated it until 1990. Vermiculite concentrate from the Libby mine was used in the manufacture of attic insulation and other products. Some of the vermiculite ore contained naturally occurring asbestos. Grace is engaged with the U.S. Environmental Protection Agency (the “EPA”) and other federal, state, and local governmental agencies in a remedial investigation and feasibility study (“RI/FS”) of the Libby mine and the surrounding area, known as Operable Unit 3 (“OU3”). The RI/FS will determine the specific areas within OU3 requiring remediation and will identify possible remedial action alternatives. Possible remedial actions within OU3 are wide-ranging, from institutional controls such as land use restrictions, to more active measures involving soil removal, containment projects, or other protective measures. As part of the RI/FS process, Grace contracted an engineering and consulting firm to develop a range of possible remedial alternatives and associated cost estimates for OU3. Based on this work, Grace recorded a pre-tax charge of $70.0 million in the 2018 third quarter for the estimated costs of remediation of OU3. Grace believes that this amount should provide for a protective remedy meeting the statutory requirements of the Comprehensive Environmental Response, Compensation, and Liability Act. The estimated costs of remediation are preliminary and consist of several components, each of which may vary significantly as the remedial alternatives are further developed. It is reasonably possible that the ultimate costs of remediation could range between $30 million and $170 million . Grace is working closely with the EPA, and the ultimate remedy will be determined by the EPA after the RI/FS is finalized. Such remedy will be set forth in a Record of Decision (“ROD”) that is currently expected to be issued by the EPA no earlier than 2022. Costs associated with the more active remedial alternatives would be expected to be incurred over a decade or more. Grace will reevaluate its estimated liability as remedial alternatives evolve based on further work by the engineering and consulting firm and discussions with the EPA as the RI/FS process moves toward a ROD. Technical memoranda expected prior to the issuance of the ROD may provide insight into the likely remedial alternatives ultimately selected, allowing Grace to update its cost of remediation estimate. Depending on the remedial alternatives that the EPA selects in the ROD, the total cost of remediating OU3 may exceed Grace’s current estimate by material amounts. Grace has cooperated with the EPA in investigating and remediating a number of formerly owned or operated sites that processed Libby vermiculite into finished products. Grace has recorded a liability for remaining expected EPA response and oversight costs, and for potential future site remediation, where a review has indicated that liability is probable and the cost is estimable. The EPA may commence additional investigations in the future at other sites that processed Libby vermiculite. Liability for unaccrued additional investigation and remediation costs is probable but not yet estimable, and could be material. Grace’s estimated liability for response costs that are currently estimable for OU3 and vermiculite processing sites outside of Libby at March 31, 2020 , and December 31, 2019 , totaled $73.9 million and $76.0 million , respectively. It is possible that Grace’s ultimate liability for these vermiculite-related matters will exceed current estimates by material amounts. Non-Vermiculite-Related Environmental Matters At March 31, 2020 , and December 31, 2019 , Grace’s estimated legacy environmental liability for response costs at sites not related to its former vermiculite mining and processing activities totaled $38.9 million and $39.3 million , respectively. This liability relates to Grace’s former businesses or operations, including its share of liability at off-site disposal facilities. Grace’s estimated liability is based upon regulatory requirements and environmental conditions at each site. As Grace receives new information, its estimated liability may change materially. Other Legacy Liabilities In April 2019, the Montana Department of Natural Resources and Conservation issued a five-year operating permit for a dam at the Libby mine site. Grace constructed the dam in 1971 to prevent vermiculite ore tailings from moving into nearby creeks and rivers. The permit requires Grace to complete construction of a new spillway before the permit is further renewed in five years. Grace contracted a third-party engineering and consulting firm to develop a range of cost estimates for the project. Based on this work, Grace recorded pre-tax charges of $68.0 million in 2019 for the estimated costs of the project. These costs are preliminary and may vary significantly as the project progresses. Based on the consultants’ estimates, Grace believes it is reasonably possible that the ultimate costs of this project could range between $50 million and $100 million . Construction of the new spillway is expected to take three to four years . Commercial and Financial Commitments and Contingencies Purchase Commitments Grace uses purchase commitments to ensure supply and to minimize the volatility of major components of direct manufacturing costs including natural gas, certain metals, rare earths, and other materials. Such commitments are for quantities that Grace fully expects to use in its normal operations. Guarantees and Indemnification Obligations Grace is a party to many contracts containing guarantees and indemnification obligations. These contracts primarily consist of: • Product warranties with respect to certain products sold to customers in the ordinary course of business. These warranties typically provide that products will conform to specifications. Grace accrues a warranty liability on a transaction-specific basis depending on the individual facts and circumstances related to each sale. • Performance guarantees offered to customers under certain licensing arrangements. Grace has not established a liability for these arrangements based on past performance. • Licenses of intellectual property by Grace to third parties in which Grace has agreed to indemnify the licensee against third party infringement claims. • Contracts providing for the sale or spin-off of a former business unit or product line in which Grace has agreed to indemnify the buyer or resulting entity against certain liabilities related to activities prior to the closing of the transaction, including environmental, tax, and employee liabilities. • Indemnification obligations of Grace as a tenant of real property leases; and guarantees of real property lease obligations of third parties, typically arising out of (a) leases entered into by former subsidiaries of Grace, or (b) the assignment or sublease of a lease by Grace to a third party. Financial Assurances Financial assurances have been established for a variety of purposes, including insurance and environmental matters, trade-related commitments and other matters. As of March 31, 2020 , Grace had gross financial assurances issued and outstanding of $138.1 million , composed of $68.9 million of surety bonds issued by various insurance companies and $69.2 million of standby letters of credit and other financial assurances issued by various banks.

Restructuring Expenses and Repo

Restructuring Expenses and Repositioning Expenses	3 Months Ended
	Mar. 31, 2020
Restructuring and Related Activities [Abstract]
Restructuring Expenses and Repositioning Expenses	Restructuring Expenses Restructuring costs in in the three months ended March 31, 2020 and 2019 , primarily related to severance costs pertaining to sales force reorganization. These costs are included in “restructuring and repositioning expenses” in the Consolidated Statements of Operations, and are not included in segment operating income. The following table presents restructuring expenses by reportable segment for the three months ended March 31, 2020 and 2019 . Three Months Ended March 31, (In millions) 2020 2019 Catalysts Technologies $ — $ 0.2 Materials Technologies 0.2 1.0 Corporate — (0.1 ) Total restructuring expenses $ 0.2 $ 1.1 The following table presents components of the change in the restructuring liability from December 31, 2019 , to March 31, 2020 . (In millions) Balance, December 31, 2019 $ 3.8 Accruals for severance and other costs 0.2 Payments (1.0 ) Balance, March 31, 2020 $ 3.0 Substantially all costs related to the restructuring programs are expected to be paid by December 31, 2021, but could be paid earlier subject to negotiations around certain plant exit costs. Repositioning Expenses Repositioning expenses for the three months ended March 31, 2020 and 2019 , were $2.5 million and $1.2 million , respectively. These expenses primarily related to a multi-year program to transform manufacturing and business processes to extend Grace’s competitive advantages and improve its cost position. Substantially all of these expenses have been or are expected to be settled in cash.

Other (Income) Expense, net

Other (Income) Expense, net	3 Months Ended
	Mar. 31, 2020
Other Income and Expenses [Abstract]
Other (Income) Expense, net	Components of other (income) expense, net are as follows: Three Months Ended March 31, (In millions) 2020 2019 Business interruption insurance recoveries $ (8.0 ) $ — Defined benefit pension (income) expense other than service cost (3.9 ) (1.5 ) Third-party acquisition-related costs 1.5 0.3 Currency transaction effects (0.9 ) (0.2 ) Net (gain) loss on sales of investments and disposals of assets 0.5 0.5 Other miscellaneous (income) expense 2.0 (1.3 ) Total other (income) expense, net $ (8.8 ) $ (2.2 ) In July 2019, a North American FCC catalysts customer filed for bankruptcy protection after announcing it would not resume refinery operations following a fire in its refinery. Grace received $8.0 million in 2020, as well as $8.0 million in the 2019 fourth quarter, from its third-party insurer under its business interruption insurance policy for lost profits.

Other Comprehensive Income (Los

Other Comprehensive Income (Loss)	3 Months Ended
	Mar. 31, 2020
Equity [Abstract]
Other Comprehensive Income (Loss)	The following tables present the pre-tax, tax, and after-tax components of Grace’s other comprehensive income (loss) for the three months ended March 31, 2020 and 2019 : Three Months Ended March 31, 2020 Pre-Tax Amount Tax Benefit/ (Expense) After-Tax Amount Amortization of net prior service credit included in net periodic benefit cost and other costs (credits), net $ (0.1 ) $ — $ (0.1 ) Currency translation adjustments 3.9 (1.4 ) 2.5 Gain (loss) from hedging activities (1.4 ) 0.4 (1.0 ) Other comprehensive income (loss) attributable to W. R. Grace & Co. shareholders $ 2.4 $ (1.0 ) $ 1.4 Three Months Ended March 31, 2019 Pre-Tax Amount Tax Benefit/ (Expense) After-Tax Amount Amortization of net prior service credit included in net periodic benefit cost and other costs (credits), net $ (0.1 ) $ — $ (0.1 ) Currency translation adjustments 12.9 (1.2 ) 11.7 Gain (loss) from hedging activities (4.3 ) 1.3 (3.0 ) Other comprehensive income (loss) attributable to W. R. Grace & Co. shareholders $ 8.5 $ 0.1 $ 8.6 The following tables present the changes in accumulated other comprehensive income (loss), net of tax, for the three months ended March 31, 2020 and 2019 : Three Months Ended March 31, 2020 Defined Benefit Pension and Other Postretirement Plans Currency Translation Adjustments Gain (Loss) from Hedging Activities Total Beginning balance $ (0.5 ) $ 92.7 $ (13.4 ) $ 78.8 Other comprehensive income (loss) before reclassifications — 2.5 7.2 9.7 Amounts reclassified from accumulated other comprehensive income (loss) (0.1 ) — (8.2 ) (8.3 ) Net current-period other comprehensive income (loss) (0.1 ) 2.5 (1.0 ) 1.4 Ending balance $ (0.6 ) $ 95.2 $ (14.4 ) $ 80.2 Three Months Ended March 31, 2019 Defined Benefit Pension and Other Postretirement Plans Currency Translation Adjustments Gain (Loss) from Hedging Activities Total Beginning balance $ 0.2 $ 76.2 $ (8.5 ) $ 67.9 Other comprehensive income (loss) before reclassifications — 11.7 6.6 18.3 Amounts reclassified from accumulated other comprehensive income (loss) (0.1 ) — (9.6 ) (9.7 ) Net current-period other comprehensive income (loss) (0.1 ) 11.7 (3.0 ) 8.6 Ending balance $ 0.1 $ 87.9 $ (11.5 ) $ 76.5 Grace is a global enterprise operating in many countries with local currency generally deemed to be the functional currency for accounting purposes. The currency translation amount represents the adjustments necessary to translate the balance sheets valued in local currencies to the U.S. dollar as of the end of each period presented, and to translate revenues and expenses at average exchange rates for each period presented. See Note 4 for a discussion of hedging activities. See Note 6 for a discussion of pension plans.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Earnings Per Share	The following table shows a reconciliation of the numerators and denominators used in calculating basic and diluted earnings per share. Three Months Ended March 31, (In millions, except per share amounts) 2020 2019 Numerators Net income (loss) attributable to W. R. Grace & Co. shareholders $ 42.0 $ 24.7 Denominators Weighted average common shares—basic calculation 66.5 66.8 Dilutive effect of employee stock options — 0.1 Weighted average common shares—diluted calculation 66.5 66.9 Basic earnings per share $ 0.63 $ 0.37 Diluted earnings per share $ 0.63 $ 0.37 There were 1.7 million anti-dilutive options outstanding for the three months ended March 31, 2020 , compared with 0.9 million for the prior-year quarter . On February 8, 2017, the Company announced that its Board of Directors authorized a share repurchase program of up to $250 million . On February 28, 2020, Grace announced that its Board of Directors had increased its share repurchase authorization to $250 million , including approximately $83 million remaining under the previously announced program. The timing of the repurchases and the actual amount repurchased will depend on a variety of factors, including the market price of the Company’s shares, strategic priorities for the deployment of capital, and general market and economic conditions. During the three months ended March 31, 2020 and 2019 , the Company repurchased 673,807 shares and 69,860 shares of Company common stock for $40.4 million and $4.8 million , respectively, pursuant to the terms of the share repurchase program. As of March 31, 2020 , $235.0 million remained under the current authorization. Grace temporarily suspended its share repurchase program in early March in light of the COVID-19 pandemic.

Revenues

Revenues	3 Months Ended
	Mar. 31, 2020
Revenues [Abstract]
Revenues	Grace generates revenues from customer arrangements primarily by manufacturing and delivering specialty chemicals and specialty materials, and by licensing technology through its two reportable segments. See Note 14 for additional information about Grace’s reportable segments. Disaggregation of Revenue The following tables present Grace's revenues by geography and product group, within its respective reportable segments, for the three months ended March 31, 2020 and 2019 . Three Months Ended March 31, 2020 North America Europe Middle East Africa (EMEA) Asia Pacific Latin America Total Refining Catalysts $ 55.7 $ 75.9 $ 31.5 $ 5.5 $ 168.6 Polyolefin and Chemical Catalysts 35.3 52.7 46.6 4.8 139.4 Total Catalysts Technologies 91.0 128.6 78.1 10.3 308.0 Consumer/Pharma 10.3 13.6 4.8 4.8 33.5 Coatings 7.2 18.4 8.6 2.4 36.6 Chemical process 8.2 19.0 8.7 1.9 37.8 Other 1.4 4.1 0.1 — 5.6 Total Materials Technologies 27.1 55.1 22.2 9.1 113.5 Total Grace $ 118.1 $ 183.7 $ 100.3 $ 19.4 $ 421.5 Three Months Ended March 31, 2019 North America EMEA Asia Pacific Latin America Total Refining Catalysts $ 72.2 $ 66.6 $ 35.7 $ 7.3 $ 181.8 Polyolefin and Chemical Catalysts 45.8 64.9 52.4 4.8 167.9 Total Catalysts Technologies 118.0 131.5 88.1 12.1 349.7 Consumer/Pharma 9.3 19.0 4.0 4.7 37.0 Coatings 7.0 19.7 9.4 2.1 38.2 Chemical process 9.0 19.9 7.7 2.3 38.9 Other 1.2 4.5 — — 5.7 Total Materials Technologies 26.5 63.1 21.1 9.1 119.8 Total Grace $ 144.5 $ 194.6 $ 109.2 $ 21.2 $ 469.5 Contract Balances Grace invoices customers for product sales once performance obligations have been satisfied, generally at the point of delivery, at which point payment becomes unconditional. Accordingly, Grace's product sales contracts generally do not give rise to material contract assets or liabilities under ASC 606; however, from time to time certain customers may pay in advance, which results in a contract liability. In the technology licensing business, Grace invoices licensees based on milestones achieved but has obligations to provide services in future periods, which results in contract liabilities. The following table presents Grace’s deferred revenue balances as of March 31, 2020 , and December 31, 2019 : (In millions) March 31, December 31, Current $ 34.8 $ 35.0 Noncurrent 30.0 29.5 Total $ 64.8 $ 64.5 Grace records deferred revenues when cash payments are received or due in advance of performance. The change in deferred revenue reflects cash payments from customers received or due in advance of satisfying performance obligations, offset by $8.4 million of revenue recognized for the three months ended March 31, 2020 , that was included in the deferred revenue balance as of December 31, 2019 . The noncurrent portion of deferred revenue will be recognized as performance obligations under the technology licensing agreements are satisfied, which is expected to be over the next five years . Remaining performance obligations represent the estimated revenue expected to be recognized in the future related to performance obligations that are unsatisfied (or partially unsatisfied). The aggregate amount of the transaction price allocated to remaining performance obligations for such contracts with a duration of more than one year was approximately $128 million as of March 31, 2020 , and includes certain amounts reported as deferred revenue above. In accordance with the available practical expedient, Grace does not disclose information about remaining performance obligations that have original expected durations of one year or less, which generally relate to customer prepayments on product sales and are generally satisfied in less than one year. Grace expects to recognize revenue related to remaining performance obligations over several years, as follows: Year Approximate percentage of revenue related to remaining performance obligations recognized 2020 20 % 2021 29 % 2022 22 % 2023 15 % Thereafter through 2027 14 % For the three months ended March 31, 2020 and 2019 , revenue recognized from performance obligations related to prior periods was not material. Grace has not capitalized any costs to obtain or fulfill contracts with customers under ASC 606. No material impairment losses have been recognized on any receivables or contract assets arising from contracts with customers.

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2020
Segment Reporting [Abstract]
Segment Information	Grace is a global producer of specialty chemicals and specialty materials. Grace’s two reportable business segments are Grace Catalysts Technologies and Grace Materials Technologies. Grace Catalysts Technologies includes catalysts and related products and technologies used in petrochemical, refining, and other chemical manufacturing applications. Advanced Refining Technologies LLC (“ART”), Grace’s joint venture with Chevron Products Company (“Chevron”), a division of Chevron U.S.A. Inc., is managed in this segment. (See Note 15.) Grace Catalysts Technologies comprises two operating segments, Grace Refining Technologies and Grace Specialty Catalysts, which are aggregated into one reportable segment based upon similar economic characteristics, the nature of the products and production processes, type and class of customer, and channels of distribution. Grace Materials Technologies includes specialty materials, including silica-based and silica-alumina-based materials, used in consumer/pharma, coatings, and chemical process applications. The table below presents information related to Grace’s reportable segments. Only those corporate expenses directly related to the reportable segments are allocated for reporting purposes. All remaining corporate items are reported separately and labeled as such. Grace excludes defined benefit pension expense from the calculation of segment operating income. Grace believes that the exclusion of defined benefit pension expense provides a better indicator of its reportable segment performance as defined benefit pension expense is not managed at a reportable segment level. Grace defines Adjusted EBIT to be net income attributable to W. R. Grace & Co. shareholders adjusted for interest income and expense; income taxes; costs related to legacy matters; restructuring and repositioning expenses and asset impairments; pension costs other than service and interest costs, expected returns on plan assets, and amortization of prior service costs/credits; gains and losses on sales or exits of businesses, product lines, and certain other investments; third-party acquisition-related costs and the amortization of acquired inventory fair value adjustment; the effects of these items on equity in earnings of unconsolidated affiliate; and certain other items that are not representative of underlying trends. Reportable Segment Data Three Months Ended March 31, (In millions) 2020 2019 Net Sales Catalysts Technologies $ 308.0 $ 349.7 Materials Technologies 113.5 119.8 Total $ 421.5 $ 469.5 Adjusted EBIT Catalysts Technologies segment operating income $ 82.0 $ 101.7 Materials Technologies segment operating income 19.0 24.0 Corporate costs (15.6 ) (16.2 ) Certain pension costs (3.1 ) (4.8 ) Total $ 82.3 $ 104.7 Corporate costs include functional costs and other costs such as professional fees, incentive compensation, and insurance premiums. Certain pension costs include only ongoing costs recognized quarterly, which include service and interest costs, expected returns on plan assets, and amortization of prior service costs/credits. Reconciliation of Reportable Segment Data to Financial Statements Grace Adjusted EBIT for the three months ended March 31, 2020 and 2019 , is reconciled below to “income (loss) before income taxes” presented in the accompanying Consolidated Statements of Operations. Three Months Ended March 31, (In millions) 2020 2019 Grace Adjusted EBIT $ 82.3 $ 104.7 Costs related to legacy matters (2.7 ) (46.9 ) Restructuring and repositioning expenses (2.7 ) (2.3 ) Third-party acquisition-related costs (1.5 ) (0.3 ) Taxes and interest included in equity in earnings of unconsolidated affiliate — (0.3 ) Interest expense, net (17.7 ) (19.3 ) Net income (loss) attributable to noncontrolling interests 0.1 (0.1 ) Income (loss) before income taxes $ 57.8 $ 35.5 Geographic Area Data The table below presents information related to the geographic areas in which Grace operates. Sales are attributed to geographic areas based on the location to which the product is transported. Three Months Ended March 31, (In millions) 2020 2019 Net Sales United States $ 106.7 $ 131.6 Canada 11.4 12.9 Total North America 118.1 144.5 Europe Middle East Africa 183.7 194.6 Asia Pacific 100.3 109.2 Latin America 19.4 21.2 Total $ 421.5 $ 469.5

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2020
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments and Joint Ventures Disclosure	Unconsolidated Affiliate Grace accounts for its 50% ownership interest in ART, its joint venture with Chevron, using the equity method of accounting. Grace’s investment in ART amounted to $182.6 million and $181.9 million as of March 31, 2020 , and December 31, 2019 , respectively. ART is a private, limited liability company, taxed as a partnership, and accordingly does not have a quoted market price available. The table below presents the components of Grace’s “equity in earnings of unconsolidated affiliate” in the Consolidated Statements of Operations. Three Months Ended March 31, (In millions) 2020 2019 Operating income $ 1.6 $ 3.9 Depreciation and amortization (0.4 ) (0.1 ) Interest expense and income taxes — 0.3 Equity in earnings of unconsolidated affiliate $ 1.2 $ 4.1 The table below presents summary financial data related to ART’s balance sheet and results of operations. (In millions) March 31, December 31, Summary Balance Sheet information: Current assets $ 281.8 $ 300.7 Noncurrent assets 249.5 237.8 Total assets $ 531.3 $ 538.5 Current liabilities $ 168.5 $ 177.1 Noncurrent liabilities 0.3 0.3 Total liabilities $ 168.8 $ 177.4 Three Months Ended March 31, (In millions) 2020 2019 Summary Statement of Operations information: Net sales $ 75.3 $ 111.5 Costs and expenses applicable to net sales 68.0 97.3 Income before income taxes 2.9 9.7 Net income 2.5 9.2 Grace and ART transact business on a regular basis and maintain several agreements in order to operate the joint venture. These agreements and the resulting transactions are treated as related party activities with an unconsolidated affiliate. Product manufactured by Grace for ART is accounted for on a net basis, with a mark-up, which reduces “cost of goods sold” in the Consolidated Statements of Operations. Grace also receives reimbursement from ART for fixed costs; research and development; selling, general and administrative services; and depreciation. Grace records reimbursements against the respective line items on Grace’s Consolidated Statements of Operations. The table below presents summary financial data related to transactions between Grace and ART. Three Months Ended March 31, (In millions) 2020 2019 Product manufactured for ART $ 71.1 $ 66.8 Mark-up on product manufactured for ART included as a reduction of Grace’s cost of goods sold 1.4 1.3 Charges for fixed costs; research and development; selling, general and administrative services; and depreciation to ART 14.1 12.8 The table below presents balances in Grace’s Consolidated Financial Statements related to ART. (in millions) March 31, December 31, Accounts receivable $ 19.5 $ 17.5 Current asset 184.7 173.9 Accounts payable 27.5 37.7 Debt payable within one year 9.8 9.9 Debt payable after one year 37.2 37.5 Current liability 184.7 173.9 The current asset and current liability in the table above represent spending to date related to a residue hydroprocessing catalyst production plant that is under construction in Lake Charles, Louisiana. Grace manages the design and construction of the plant, and the asset will continue to be included in “other current assets” in Grace’s Consolidated Balance Sheets until construction is completed. Grace has likewise recorded a liability for the transfer of the asset to ART upon completion, included in “other current liabilities” in the Consolidated Balance Sheets. Grace and ART maintain an agreement whereby ART loans Grace funds for maintenance capital expenditures at manufacturing facilities used to produce catalysts for ART. Grace makes principal and interest payments on the loans on a monthly basis. These unsecured loans have repayment terms of up to eight years , unless earlier repayment is demanded by ART. The loans bear interest at the three-month LIBOR plus 1.25% . Grace and Chevron provide lines of credit in the amount of $15.0 million each at a commitment fee of 0.1% of the credit amount. These agreements have been approved by the ART Executive Committee for renewal until February 2021. No amounts were outstanding at March 31, 2020 , or December 31, 2019 . Joint Venture Arrangement In 2018, Grace formed a joint venture in a developing country in Asia. The purpose of the joint venture is to establish a logistics facility and catalyst testing laboratory and to be the exclusive FCC catalysts and additives supplier to certain customers in the country. Grace’s joint venture partner is the parent company of the customers. Grace has an 87.5% ownership interest in the joint venture and consolidates the activities of the entity. Grace’s Consolidated Balance Sheets as of March 31, 2020 , and December 31, 2019 , include trade accounts receivable of $1.8 million and $3.6 million , respectively, from these customers. Grace’s Consolidated Statements of Operations for the three months ended March 31, 2020 , include $1.9 million of revenues from these customers, compared with $3.2 million in the prior-year quarter

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting and Financial Reporting Policies (Policies)	3 Months Ended
	Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The interim Consolidated Financial Statements presented herein are unaudited and should be read in conjunction with the Consolidated Financial Statements presented in the Company’s 2019 Annual Report on Form 10-K. Such interim Consolidated Financial Statements reflect all adjustments that, in the opinion of management, are necessary for a fair statement of the results of the interim periods presented; all such adjustments are of a normal recurring nature except for the impacts of adopting new accounting standards as discussed below. All significant intercompany accounts and transactions have been eliminated. The results of operations for the three-month interim period ended March 31, 2020 , are not necessarily indicative of the results of operations to be attained for the year ending December 31, 2020 .
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. generally accepted accounting principles (“U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the Consolidated Financial Statements, and the reported amounts of revenues and expenses for the periods presented. Actual amounts could differ from those estimates, and the differences could be material. Changes in estimates are recorded in the period identified. Grace’s accounting measurements that are most affected by management’s estimates of future events are: • The effective tax rate and realization values of net deferred tax assets, which depend on projections of future taxable income; • Pension and postretirement liabilities, which depend on assumptions regarding participant life spans, future inflation, discount rates and total returns on invested funds (see Note 6); • Carrying values of goodwill and other intangible assets, which depend on assumptions of future earnings and cash flows; and • Contingent liabilities, which depend on an assessment of the probability of loss and an estimate of ultimate obligation, such as litigation, environmental remediation, and other legacy liabilities (see Note 8).
Reclassifications	Reclassifications
Recently Issued and Adopted Accounting Standards	Recently Issued Accounting Standards In December 2019, the FASB issued ASU 2019-12 “Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes.” This update clarifies and amends existing guidance, including removing certain exceptions to the general principles in Topic 740, and improves consistent application of and simplifies U.S. GAAP for other areas of Topic 740. This update is effective for Grace on January 1, 2021, with early adoption permitted. Grace is currently evaluating the effect and timing of adoption. Recently Adopted Accounting Standards In March 2020, the FASB issued ASU 2020-04 “Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting.” This update is intended to ease the potential burden in accounting for and recognizing the effects of reference rate reform. It provides optional practical expedients and exceptions for applying U.S. GAAP to contracts, hedging relationships, and other transactions affected by reference rate reform, if certain criteria are met. This update became effective on March 12, 2020, and is available for use through December 31, 2022. Grace expects to utilize the practical expedients provided by this update in accounting for contract modifications and/or hedging transactions during the effective period. Grace expects the update to significantly reduce the effects of reference rate reform on the Consolidated Financial Statements. In August 2018, the FASB issued ASU 2018-14 “Compensation—Retirement Benefits—Defined Benefit Plans—General (Subtopic 715-20).” This update revises disclosure requirements related to defined benefit pension and other postretirement plans. Grace adopted this update in the 2020 first quarter, and it did not have a material effect on the Consolidated Financial Statements. In June 2016, the FASB issued ASU 2016-13 “Financial Instruments—Credit Losses (Topic 326) Measurement of Credit Losses on Financial Instruments.” This update requires companies to implement an impairment model based on expected credit losses, rather than probable incurred losses. Grace adopted this update in the 2020 first quarter, and it did not have a material effect on the Consolidated Financial Statements.

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Mar. 31, 2020
Inventory Disclosure [Abstract]
Schedule of inventories	Inventories consisted of the following at March 31, 2020 , and December 31, 2019 : (In millions) March 31, December 31, Raw materials $ 64.8 $ 64.2 In process 60.8 55.7 Finished products 177.6 154.4 Other 35.9 35.6 Total inventory $ 339.1 $ 309.9

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Summary of Debt Outstanding	Components of Debt (In millions) March 31, December 31, 2018 U.S. dollar term loan, net of unamortized debt issuance costs of $6.9 (2019—$7.2) $ 928.8 $ 930.9 Senior notes due 2021, net of unamortized debt issuance costs of $2.3 (2019—$2.7) 697.7 697.3 Senior notes due 2024, net of unamortized debt issuance costs of $2.3 (2019—$2.4) 297.7 297.6 Debt payable to unconsolidated affiliate 47.0 47.4 Other borrowings 7.1 7.2 Total debt 1,978.3 1,980.4 Less debt payable within one year 23.5 23.1 Debt payable after one year $ 1,954.8 $ 1,957.3 Weighted average interest rates on total debt 3.7 % 3.8 %
Schedule of Maturities of Long-term Debt	The principal maturities of debt outstanding at March 31, 2020 , were as follows: (In millions) 2020 $ 18.6 2021 717.3 2022 18.7 2023 17.8 2024 313.3 Thereafter 892.6 Total debt $ 1,978.3

Fair Value Measurements and R_2

Fair Value Measurements and Risk (Tables)	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Schedule of Net Investment Hedges in Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The following table presents the amount of gains and losses on derivative instruments designated as net investment hedges, recorded to “currency translation adjustments” within “accumulated other comprehensive income (loss)” for the three months ended March 31, 2020 and 2019 . There were no reclassifications of the effective portion of net investment hedges out of OCI and into earnings for the periods presented. Three Months Ended March 31, (In millions) 2020 2019 Derivatives in ASC 815 net investment hedging relationships: Cross-currency swap $ 6.1 $ 3.8
Schedule of Carrying Values and Estimated Fair Values of Debt Instruments	At March 31, 2020 , and December 31, 2019 , the carrying amounts and fair values of Grace’s debt were as follows: March 31, 2020 December 31, 2019 (In millions) Carrying Amount Fair Value Carrying Amount Fair Value 2018 U.S. dollar term loan(1) $ 928.8 $ 789.5 $ 930.9 $ 938.1 Senior notes due 2021(2) 697.7 706.0 697.3 727.1 Senior notes due 2024(2) 297.7 297.7 297.6 329.2 Other borrowings 54.1 54.1 54.6 54.6 Total debt $ 1,978.3 $ 1,847.3 $ 1,980.4 $ 2,049.0 ___________________________________________________________________________________________________________________ (1) Carrying amounts are net of unamortized debt issuance costs and discounts of $6.9 million and $7.2 million as of March 31, 2020 , and December 31, 2019 , respectively. (2) Carrying amounts are net of unamortized debt issuance costs of $2.3 million and $2.3 million as of March 31, 2020 , and $2.7 million and $2.4 million as of December 31, 2019 , related to the senior notes due 2021 and senior notes due 2024, respectively.
Schedule of Fair Value of Assets and Liabilities Measured on a Recurring Basis	The following tables present the fair value hierarchy for financial assets and liabilities measured at fair value on a recurring basis as of March 31, 2020 , and December 31, 2019 : Fair Value Measurements at March 31, 2020, Using (In millions) Total Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Currency derivatives $ 14.6 $ — $ 14.6 $ — Variable-to-fixed cross-currency swaps 11.5 — 11.5 — Total Assets $ 26.1 $ — $ 26.1 $ — Liabilities Currency derivatives $ 1.2 $ — $ 1.2 $ — Interest rate derivatives 6.3 — 6.3 — Total Liabilities $ 7.5 $ — $ 7.5 $ — Fair Value Measurements at December 31, 2019, Using (In millions) Total Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Currency derivatives $ 6.1 $ — $ 6.1 $ — Variable-to-fixed cross-currency derivatives 3.4 — 3.4 — Total Assets $ 9.5 $ — $ 9.5 $ — Liabilities Currency derivatives $ 0.9 $ — $ 0.9 $ — Interest rate derivatives 3.4 — 3.4 — Total Liabilities $ 4.3 $ — $ 4.3 $ —
Schedule of the Location and Fair Values of Derivative Instruments Included in the Consolidated Balance Sheets	The following tables present the location and fair values of derivative instruments included in the Consolidated Balance Sheets as of March 31, 2020 , and December 31, 2019 : March 31, 2020 Asset Derivatives Liability Derivatives Balance Sheet Location Fair Value Balance Sheet Location Fair Value Derivatives designated as hedging instruments under ASC 815: Currency contracts Other current assets $ 6.2 Other current liabilities $ — Currency contracts Other assets 8.4 Other liabilities — Interest rate contracts Other current assets — Other current liabilities 2.1 Interest rate contracts Other assets — Other liabilities 4.2 Variable-to-fixed cross-currency swaps Other current assets 4.2 Other current liabilities — Variable-to-fixed cross-currency swaps Other assets 7.3 Other liabilities — Derivatives not designated as hedging instruments under ASC 815: Currency contracts Other current assets — Other current assets (0.5 ) Currency contracts Other current assets — Other current liabilities 1.7 Total derivatives $ 26.1 $ 7.5 December 31, 2019 Asset Derivatives Liability Derivatives Balance Sheet Location Fair Value Balance Sheet Location Fair Value Derivatives designated as hedging instruments under ASC 815: Currency contracts Other current assets $ 2.1 Other current assets $ (3.1 ) Currency contracts Other assets 4.0 Other liabilities 4.0 Interest rate contracts Other current assets — Other current liabilities 1.0 Interest rate contracts Other assets — Other liabilities 2.4 Variable-to-fixed cross-currency swaps Other current assets 10.2 Other current liabilities — Variable-to-fixed cross-currency swaps Other liabilities (6.8 ) Other liabilities — Derivatives not designated as hedging instruments under ASC 815: Currency contracts Other current assets — Other current assets (0.2 ) Currency contracts Other current assets — Other current liabilities 0.2 Total derivatives $ 9.5 $ 4.3
Schedule of Gain (Loss) on Derivative Instruments	The following tables present the location and amount of gains and losses on derivative instruments included in the Consolidated Statements of Operations or, when applicable, gains and losses initially recognized in other comprehensive income (loss) (“OCI”) for the three months ended March 31, 2020 and 2019 : Three Months Ended March 31, 2020 Amount of Gain (Loss) Recognized in OCI on Derivatives Location of Gain (Loss) Reclassified from Accumulated OCI into Income Amount of Gain (Loss) Reclassified from OCI into Income Derivatives in ASC 815 cash flow hedging relationships: Interest rate contracts $ (3.1 ) Interest expense $ (0.2 ) Currency contracts(1) 2.4 Other expense 1.4 Variable-to-fixed cross-currency swaps 3.4 Interest expense 2.5 Variable-to-fixed cross-currency swaps 7.6 Other expense 7.6 Total derivatives $ 10.3 $ 11.3 Location of Gain (Loss) Recognized in Income on Derivatives Amount of Gain (Loss) Recognized in Income on Derivatives Derivatives not designated as hedging instruments under ASC 815: Currency contracts Other expense $ (1.9 ) ___________________________________________________________________________________________________________________ (1) Amount of gain (loss) recognized in OCI includes $1.1 million excluded from the assessment of effectiveness for which the difference between changes in fair value and periodic amortization is recorded in OCI. Three Months Ended March 31, 2019 Amount of Gain (Loss) Recognized in OCI on Derivatives Location of Gain (Loss) Reclassified from Accumulated OCI into Income Amount of Gain (Loss) Reclassified from OCI into Income Derivatives in ASC 815 cash flow hedging relationships: Interest rate contracts $ (1.1 ) Interest expense $ — Currency contracts(1) 1.6 Other expense 1.3 Variable-to-fixed cross-currency swaps 0.1 Interest expense 3.6 Variable-to-fixed cross-currency swaps 8.4 Other expense 8.4 Total derivatives $ 9.0 $ 13.3 Location of Gain (Loss) Recognized in Income on Derivatives Amount of Gain (Loss) Recognized in Income on Derivatives Derivatives not designated as hedging instruments under ASC 815: Currency contracts Other expense $ (0.1 ) ___________________________________________________________________________________________________________________ (1) Amount of gain (loss) recognized in OCI includes $0.0 million excluded from the assessment of effectiveness for which the difference between changes in fair value and periodic amortization is recorded in OCI. The following table presents the total amounts of income and expense line items presented in the Consolidated Statements of Operations in which the effects of cash flow hedges are reported. Three Months Ended March 31, 2020 2019 (In millions) Interest expense Other income (expense) Interest expense Other income (expense) Total amounts of income and expense line items in the Consolidated Statements of Operations in which the effects of cash flow hedges are recorded $ (18.3 ) $ 8.8 $ (20.0 ) $ 2.2 Gain (loss) on cash flow hedging relationships in ASC 815 Interest rate contracts Gain (loss) reclassified from accumulated OCI into income $ (0.2 ) $ — $ — $ — Variable-to-fixed cross-currency swaps Gain (loss) reclassified from accumulated OCI into income 2.5 7.6 3.6 8.4 Currency contracts Gain (loss) reclassified from accumulated OCI into income — 1.4 — 1.3 Amount excluded from effectiveness testing recognized in earnings based on amortization approach (included in above) — 0.7 — 0.7

Pension Plans and Other Postr_2

Pension Plans and Other Postretirement Benefit Plans (Tables)	3 Months Ended
	Mar. 31, 2020
Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]
Schedule of net funded status of fully funded, underfunded, and unfunded pension plans	The following table presents the funded status of Grace’s pension plans: (In millions) March 31, December 31, Overfunded defined benefit pension plans $ 8.9 $ 8.5 Underfunded defined benefit pension plans (84.5 ) (85.2 ) Unfunded defined benefit pension plans (430.3 ) (434.6 ) Total underfunded and unfunded defined benefit pension plans (514.8 ) (519.8 ) Pension liabilities included in other current liabilities (14.7 ) (14.8 ) Net funded status $ (520.6 ) $ (526.1 )
Components of net periodic benefit cost (income)	The following table presents the components of net periodic benefit cost (income). Three Months Ended March 31, 2020 2019 (In millions) U.S. Non-U.S. U.S. Non-U.S. Service cost $ 4.7 $ 2.7 $ 3.9 $ 2.2 Interest cost 7.6 1.0 9.6 1.3 Expected return on plan assets (12.0 ) (0.3 ) (12.0 ) (0.2 ) Amortization of prior service credit (0.2 ) — (0.2 ) — Net periodic benefit cost (income) $ 0.1 $ 3.4 $ 1.3 $ 3.3

Other Balance Sheet Accounts (T

Other Balance Sheet Accounts (Tables)	3 Months Ended
	Mar. 31, 2020
Other Balance Sheet Accounts [Abstract]
Schedule of Other Assets and Other Liabilities	(In millions) March 31, December 31, Other Current Assets Plant under construction—unconsolidated affiliate (see Note 15) $ 184.7 $ 173.9 Non-trade accounts receivable 21.6 24.1 Fair value of currency, interest rate, and commodity contracts (see Note 4) 10.9 15.6 Income taxes receivable 9.5 4.2 Other current assets 18.4 17.3 $ 245.1 $ 235.1 (In millions) March 31, December 31, Other Current Liabilities Liability to unconsolidated affiliate for plant under construction (see Note 15) $ 184.7 $ 173.9 Accrued compensation 35.3 53.6 Deferred revenue (see Note 13) 34.8 35.0 Accrued interest (see Note 3) 26.4 13.3 Environmental contingencies (see Note 8) 18.7 17.8 Pension liabilities (see Note 6) 14.7 14.8 Income taxes payable (see Note 5) 11.5 8.6 Operating lease liabilities 8.9 9.3 Liability for dam spillway replacement (see Note 8) 4.4 4.7 Other accrued liabilities 75.2 88.7 $ 414.6 $ 419.7 Accrued compensation includes salaries and wages as well as estimated current amounts due under the annual and long-term incentive programs. (In millions) March 31, December 31, Other Liabilities Environmental contingencies (see Note 8) $ 94.1 $ 97.5 Liability for dam spillway replacement (see Note 8) 61.0 61.7 Deferred revenue (see Note 13) 30.0 29.5 Operating lease liabilities 25.4 26.2 Legacy product liability (see Note 8) 24.0 24.0 Retained obligations of divested businesses 11.9 12.7 Asset retirement obligation 9.5 9.4 Deferred income taxes 7.5 7.5 Fair value of currency and interest rate contracts (see Note 4) 4.2 13.2 Unrecognized tax benefits 4.0 4.1 Other noncurrent liabilities 22.2 22.4 $ 293.8 $ 308.2

Restructuring Expenses and Re_2

Restructuring Expenses and Repositioning Expenses (Tables)	3 Months Ended
	Mar. 31, 2020
Restructuring and Related Activities [Abstract]
Schedule of restructuring expenses and asset impairments	The following table presents restructuring expenses by reportable segment for the three months ended March 31, 2020 and 2019 . Three Months Ended March 31, (In millions) 2020 2019 Catalysts Technologies $ — $ 0.2 Materials Technologies 0.2 1.0 Corporate — (0.1 ) Total restructuring expenses $ 0.2 $ 1.1
Schedule of restructuring liability	The following table presents components of the change in the restructuring liability from December 31, 2019 , to March 31, 2020 . (In millions) Balance, December 31, 2019 $ 3.8 Accruals for severance and other costs 0.2 Payments (1.0 ) Balance, March 31, 2020 $ 3.0

Other (Income) Expense, net (Ta

Other (Income) Expense, net (Tables)	3 Months Ended
	Mar. 31, 2020
Other Income and Expenses [Abstract]
Schedule of other (income) expense, net	Components of other (income) expense, net are as follows: Three Months Ended March 31, (In millions) 2020 2019 Business interruption insurance recoveries $ (8.0 ) $ — Defined benefit pension (income) expense other than service cost (3.9 ) (1.5 ) Third-party acquisition-related costs 1.5 0.3 Currency transaction effects (0.9 ) (0.2 ) Net (gain) loss on sales of investments and disposals of assets 0.5 0.5 Other miscellaneous (income) expense 2.0 (1.3 ) Total other (income) expense, net $ (8.8 ) $ (2.2 )

Other Comprehensive Income (L_2

Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Mar. 31, 2020
Equity [Abstract]
Disclosure of pre-tax, tax, and after-tax components of other comprehensive income (loss)	The following tables present the pre-tax, tax, and after-tax components of Grace’s other comprehensive income (loss) for the three months ended March 31, 2020 and 2019 : Three Months Ended March 31, 2020 Pre-Tax Amount Tax Benefit/ (Expense) After-Tax Amount Amortization of net prior service credit included in net periodic benefit cost and other costs (credits), net $ (0.1 ) $ — $ (0.1 ) Currency translation adjustments 3.9 (1.4 ) 2.5 Gain (loss) from hedging activities (1.4 ) 0.4 (1.0 ) Other comprehensive income (loss) attributable to W. R. Grace & Co. shareholders $ 2.4 $ (1.0 ) $ 1.4 Three Months Ended March 31, 2019 Pre-Tax Amount Tax Benefit/ (Expense) After-Tax Amount Amortization of net prior service credit included in net periodic benefit cost and other costs (credits), net $ (0.1 ) $ — $ (0.1 ) Currency translation adjustments 12.9 (1.2 ) 11.7 Gain (loss) from hedging activities (4.3 ) 1.3 (3.0 ) Other comprehensive income (loss) attributable to W. R. Grace & Co. shareholders $ 8.5 $ 0.1 $ 8.6
Schedule of components of accumulated other comprehensive loss	The following tables present the changes in accumulated other comprehensive income (loss), net of tax, for the three months ended March 31, 2020 and 2019 : Three Months Ended March 31, 2020 Defined Benefit Pension and Other Postretirement Plans Currency Translation Adjustments Gain (Loss) from Hedging Activities Total Beginning balance $ (0.5 ) $ 92.7 $ (13.4 ) $ 78.8 Other comprehensive income (loss) before reclassifications — 2.5 7.2 9.7 Amounts reclassified from accumulated other comprehensive income (loss) (0.1 ) — (8.2 ) (8.3 ) Net current-period other comprehensive income (loss) (0.1 ) 2.5 (1.0 ) 1.4 Ending balance $ (0.6 ) $ 95.2 $ (14.4 ) $ 80.2 Three Months Ended March 31, 2019 Defined Benefit Pension and Other Postretirement Plans Currency Translation Adjustments Gain (Loss) from Hedging Activities Total Beginning balance $ 0.2 $ 76.2 $ (8.5 ) $ 67.9 Other comprehensive income (loss) before reclassifications — 11.7 6.6 18.3 Amounts reclassified from accumulated other comprehensive income (loss) (0.1 ) — (9.6 ) (9.7 ) Net current-period other comprehensive income (loss) (0.1 ) 11.7 (3.0 ) 8.6 Ending balance $ 0.1 $ 87.9 $ (11.5 ) $ 76.5

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Schedule of reconciliation of the numerators and denominators used in calculating basic and diluted earnings per share	The following table shows a reconciliation of the numerators and denominators used in calculating basic and diluted earnings per share. Three Months Ended March 31, (In millions, except per share amounts) 2020 2019 Numerators Net income (loss) attributable to W. R. Grace & Co. shareholders $ 42.0 $ 24.7 Denominators Weighted average common shares—basic calculation 66.5 66.8 Dilutive effect of employee stock options — 0.1 Weighted average common shares—diluted calculation 66.5 66.9 Basic earnings per share $ 0.63 $ 0.37 Diluted earnings per share $ 0.63 $ 0.37

Revenues (Tables)

Revenues (Tables)	3 Months Ended
	Mar. 31, 2020
Revenues [Abstract]
Schedule of Disaggregated of Revenue	The following tables present Grace's revenues by geography and product group, within its respective reportable segments, for the three months ended March 31, 2020 and 2019 . Three Months Ended March 31, 2020 North America Europe Middle East Africa (EMEA) Asia Pacific Latin America Total Refining Catalysts $ 55.7 $ 75.9 $ 31.5 $ 5.5 $ 168.6 Polyolefin and Chemical Catalysts 35.3 52.7 46.6 4.8 139.4 Total Catalysts Technologies 91.0 128.6 78.1 10.3 308.0 Consumer/Pharma 10.3 13.6 4.8 4.8 33.5 Coatings 7.2 18.4 8.6 2.4 36.6 Chemical process 8.2 19.0 8.7 1.9 37.8 Other 1.4 4.1 0.1 — 5.6 Total Materials Technologies 27.1 55.1 22.2 9.1 113.5 Total Grace $ 118.1 $ 183.7 $ 100.3 $ 19.4 $ 421.5 Three Months Ended March 31, 2019 North America EMEA Asia Pacific Latin America Total Refining Catalysts $ 72.2 $ 66.6 $ 35.7 $ 7.3 $ 181.8 Polyolefin and Chemical Catalysts 45.8 64.9 52.4 4.8 167.9 Total Catalysts Technologies 118.0 131.5 88.1 12.1 349.7 Consumer/Pharma 9.3 19.0 4.0 4.7 37.0 Coatings 7.0 19.7 9.4 2.1 38.2 Chemical process 9.0 19.9 7.7 2.3 38.9 Other 1.2 4.5 — — 5.7 Total Materials Technologies 26.5 63.1 21.1 9.1 119.8 Total Grace $ 144.5 $ 194.6 $ 109.2 $ 21.2 $ 469.5
Schedule of Deferred Revenues	The following table presents Grace’s deferred revenue balances as of March 31, 2020 , and December 31, 2019 : (In millions) March 31, December 31, Current $ 34.8 $ 35.0 Noncurrent 30.0 29.5 Total $ 64.8 $ 64.5
Schedule of Remaining Performance Obligations	Grace expects to recognize revenue related to remaining performance obligations over several years, as follows: Year Approximate percentage of revenue related to remaining performance obligations recognized 2020 20 % 2021 29 % 2022 22 % 2023 15 % Thereafter through 2027 14 %

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2020
Segment Reporting [Abstract]
Schedule of operating segment data	Reportable Segment Data Three Months Ended March 31, (In millions) 2020 2019 Net Sales Catalysts Technologies $ 308.0 $ 349.7 Materials Technologies 113.5 119.8 Total $ 421.5 $ 469.5 Adjusted EBIT Catalysts Technologies segment operating income $ 82.0 $ 101.7 Materials Technologies segment operating income 19.0 24.0 Corporate costs (15.6 ) (16.2 ) Certain pension costs (3.1 ) (4.8 ) Total $ 82.3 $ 104.7
Schedule of reconciliation of operating segment data to financial statements	Grace Adjusted EBIT for the three months ended March 31, 2020 and 2019 , is reconciled below to “income (loss) before income taxes” presented in the accompanying Consolidated Statements of Operations. Three Months Ended March 31, (In millions) 2020 2019 Grace Adjusted EBIT $ 82.3 $ 104.7 Costs related to legacy matters (2.7 ) (46.9 ) Restructuring and repositioning expenses (2.7 ) (2.3 ) Third-party acquisition-related costs (1.5 ) (0.3 ) Taxes and interest included in equity in earnings of unconsolidated affiliate — (0.3 ) Interest expense, net (17.7 ) (19.3 ) Net income (loss) attributable to noncontrolling interests 0.1 (0.1 ) Income (loss) before income taxes $ 57.8 $ 35.5
Schedule of geographic area data	The table below presents information related to the geographic areas in which Grace operates. Sales are attributed to geographic areas based on the location to which the product is transported. Three Months Ended March 31, (In millions) 2020 2019 Net Sales United States $ 106.7 $ 131.6 Canada 11.4 12.9 Total North America 118.1 144.5 Europe Middle East Africa 183.7 194.6 Asia Pacific 100.3 109.2 Latin America 19.4 21.2 Total $ 421.5 $ 469.5

Related Party Transactions (Tab

Related Party Transactions (Tables)	3 Months Ended
	Mar. 31, 2020
Equity Method Investments and Joint Ventures [Abstract]
Summary of financial information of equity method investee	The table below presents summary financial data related to ART’s balance sheet and results of operations. (In millions) March 31, December 31, Summary Balance Sheet information: Current assets $ 281.8 $ 300.7 Noncurrent assets 249.5 237.8 Total assets $ 531.3 $ 538.5 Current liabilities $ 168.5 $ 177.1 Noncurrent liabilities 0.3 0.3 Total liabilities $ 168.8 $ 177.4 Three Months Ended March 31, (In millions) 2020 2019 Summary Statement of Operations information: Net sales $ 75.3 $ 111.5 Costs and expenses applicable to net sales 68.0 97.3 Income before income taxes 2.9 9.7 Net income 2.5 9.2
Schedule of financial data related to transactions between Grace and ART	The table below presents summary financial data related to transactions between Grace and ART. Three Months Ended March 31, (In millions) 2020 2019 Product manufactured for ART $ 71.1 $ 66.8 Mark-up on product manufactured for ART included as a reduction of Grace’s cost of goods sold 1.4 1.3 Charges for fixed costs; research and development; selling, general and administrative services; and depreciation to ART 14.1 12.8 The table below presents balances in Grace’s Consolidated Financial Statements related to ART. (in millions) March 31, December 31, Accounts receivable $ 19.5 $ 17.5 Current asset 184.7 173.9 Accounts payable 27.5 37.7 Debt payable within one year 9.8 9.9 Debt payable after one year 37.2 37.5 Current liability 184.7 173.9

Basis of Presentation and Sum_3

Basis of Presentation and Summary of Significant Accounting and Financial Reporting Policies - Narrative (Details)	3 Months Ended
	Mar. 31, 2020segment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of reportable segments	2

Inventories (Details)

Inventories (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Raw materials	$ 64.8	$ 64.2
In process	60.8	55.7
Finished products	177.6	154.4
Other	35.9	35.6
Total inventory	$ 339.1	$ 309.9

Debt - Components of Debt (Deta

Debt - Components of Debt (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Debt payable—unconsolidated affiliate	$ 47	$ 47.4
Total debt	1,978.3	1,980.4
Debt payable within one year	23.5	23.1
Debt payable after one year	$ 1,954.8	$ 1,957.3
Weighted average interest rates on total debt	3.70%	3.80%
2025 Term Loan
Debt Instrument [Line Items]
Total debt	$ 928.8	$ 930.9
Unamortized discount and debt issuance costs	6.9	7.2
5.125% Senior Notes, Due 2021
Debt Instrument [Line Items]
Total debt	697.7	697.3
Debt Issuance Costs, Net	2.3	2.7
5.625% Senior Notes, Due 2024
Debt Instrument [Line Items]
Total debt	297.7	297.6
Debt Issuance Costs, Net	2.3	2.4
Other borrowings
Debt Instrument [Line Items]
Total debt	$ 7.1	$ 7.2

Debt - Narrative (Details)

Debt - Narrative (Details) - Revolving Credit Facility - USD ($) $ in Millions	Mar. 31, 2020	Apr. 03, 2018
Debt Instrument [Line Items]
Senior notes issued		$ 400
Current borrowing capacity	$ 381.3

Debt - Debt Maturity Schedule (

Debt - Debt Maturity Schedule (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Maturities of Long-term Debt [Abstract]
Remainder of Fiscal Year	$ 18.6
Year Two	717.3
Year Three	18.7
Year Four	17.8
Year Five	313.3
Thereafter	892.6
Total debt	$ 1,978.3	$ 1,980.4

Fair Value Measurements and R_3

Fair Value Measurements and Risk - Carrying Amounts and Fair Values of Debt (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	$ 1,978.3	$ 1,980.4
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other borrowings	54.1	54.6
Total debt	1,978.3	1,980.4
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other borrowings	54.1	54.6
Total debt	1,847.3	2,049
2025 Term Loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	928.8	930.9
Unamortized discount and debt issuance costs	6.9	7.2
2025 Term Loan | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	928.8	930.9
2025 Term Loan | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	789.5	938.1
5.125% Senior Notes, Due 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	697.7	697.3
Debt Issuance Costs, Net	2.3	2.7
5.125% Senior Notes, Due 2021 | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	697.7	697.3
5.125% Senior Notes, Due 2021 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	706	727.1
5.625% Senior Notes, Due 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	297.7	297.6
Debt Issuance Costs, Net	2.3	2.4
5.625% Senior Notes, Due 2024 | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	297.7	297.6
5.625% Senior Notes, Due 2024 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	$ 297.7	$ 329.2

Fair Value Measurements and R_4

Fair Value Measurements and Risk - Narrative (Details) € in Millions	3 Months Ended
	Mar. 31, 2020USD ($)	Mar. 31, 2019USD ($)	Mar. 31, 2020EUR (€)Currencycountry	Mar. 31, 2020USD ($)Currencycountry	Nov. 05, 2018EUR (€)	Nov. 05, 2018USD ($)	Apr. 03, 2018USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of countries in which entity operates | country			60	60
Number of currencies used | Currency			30	30
Maturities in which forward contracts are designated as cash flow hedges or forecasted repayments of intercompany loans	36 months
Currency contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Notional Amount				$ 155,500,000
Variable-to-fixed cross-currency swaps | 2018 Credit Agreement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amount of debt hedged						$ 600,000,000
Derivative, Notional Amount | €					€ 525.9
Fixed interest rate					1.785%	1.785%
Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amount of debt hedged							$ 100,000,000
Fixed interest rate							2.775%
Net Investment Hedging
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ 0	$ 0
Net Investment Hedging | Currency Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), Adjustments, before Tax	$ 900,000	$ 800,000
Derivative, Notional Amount | €			€ 170

Fair Value Measurements and R_5

Fair Value Measurements and Risk - Financial Asset and Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	$ 26.1	$ 9.5
Total derivatives	7.5	4.3
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	26.1	9.5
Total derivatives	7.5	4.3
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	0	0
Total derivatives	0	0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	26.1	9.5
Total derivatives	7.5	4.3
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	0	0
Total derivatives	0	0
Currency derivatives | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	14.6	6.1
Total derivatives	1.2	0.9
Currency derivatives | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	0	0
Total derivatives	0	0
Currency derivatives | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	14.6	6.1
Total derivatives	1.2	0.9
Currency derivatives | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	0	0
Total derivatives	0	0
Interest rate derivatives | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivatives	6.3	3.4
Interest rate derivatives | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivatives	0	0
Interest rate derivatives | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivatives	6.3	3.4
Interest rate derivatives | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivatives	0	0
Variable-to-fixed cross-currency swaps | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	11.5	3.4
Variable-to-fixed cross-currency swaps | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	0	0
Variable-to-fixed cross-currency swaps | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	11.5	3.4
Variable-to-fixed cross-currency swaps | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	$ 0	$ 0

Fair Value Measurements and R_6

Fair Value Measurements and Risk - Derivative Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Asset Derivatives
Total derivatives	$ 26.1	$ 9.5
Liability Derivatives
Total derivatives	7.5	4.3
Currency contracts | Derivatives designated as hedging instruments under ASC 815: | Other current assets
Asset Derivatives
Total derivatives	6.2	2.1
Liability Derivatives
Total derivatives		(3.1)
Currency contracts | Derivatives designated as hedging instruments under ASC 815: | Other assets
Asset Derivatives
Total derivatives	8.4	4
Currency contracts | Derivatives designated as hedging instruments under ASC 815: | Other current liabilities
Liability Derivatives
Total derivatives	0
Currency contracts | Derivatives designated as hedging instruments under ASC 815: | Other liabilities
Liability Derivatives
Total derivatives	0	4
Currency contracts | Derivatives not designated as hedging instruments under ASC 815: | Other current assets
Asset Derivatives
Total derivatives	0	0
Liability Derivatives
Total derivatives	(0.5)	(0.2)
Currency contracts | Derivatives not designated as hedging instruments under ASC 815: | Other current liabilities
Liability Derivatives
Total derivatives	1.7	0.2
Interest rate contracts | Derivatives designated as hedging instruments under ASC 815: | Other current assets
Asset Derivatives
Total derivatives	0	0
Interest rate contracts | Derivatives designated as hedging instruments under ASC 815: | Other assets
Asset Derivatives
Total derivatives	0	0
Interest rate contracts | Derivatives designated as hedging instruments under ASC 815: | Other current liabilities
Liability Derivatives
Total derivatives	2.1	1
Interest rate contracts | Derivatives designated as hedging instruments under ASC 815: | Other liabilities
Liability Derivatives
Total derivatives	4.2	2.4
Variable-to-fixed cross-currency swaps | Derivatives designated as hedging instruments under ASC 815: | Other current assets
Asset Derivatives
Total derivatives	4.2	10.2
Variable-to-fixed cross-currency swaps | Derivatives designated as hedging instruments under ASC 815: | Other assets
Asset Derivatives
Total derivatives	7.3
Variable-to-fixed cross-currency swaps | Derivatives designated as hedging instruments under ASC 815: | Other current liabilities
Liability Derivatives
Total derivatives	0	0
Variable-to-fixed cross-currency swaps | Derivatives designated as hedging instruments under ASC 815: | Other liabilities
Asset Derivatives
Total derivatives		(6.8)
Liability Derivatives
Total derivatives	$ 0	$ 0

Fair Value Measurements and R_7

Fair Value Measurements and Risk - Gain (Loss) on Derivative Instruments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash Flow Hedging [Member]
Gains and losses on derivative instruments
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	$ 10.3	$ 9
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	11.3	13.3
Cash Flow Hedging [Member] | Interest rate derivatives
Gains and losses on derivative instruments
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	(3.1)	(1.1)
Cash Flow Hedging [Member] | Interest rate derivatives | Interest expense
Gains and losses on derivative instruments
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(0.2)	0
Cash Flow Hedging [Member] | Interest rate derivatives | Other expense
Gains and losses on derivative instruments
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0	0
Cash Flow Hedging [Member] | Currency contracts
Gains and losses on derivative instruments
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	2.4	1.6
Cash Flow Hedging [Member] | Currency contracts | Interest expense
Gains and losses on derivative instruments
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0	0
Cash Flow Hedging [Member] | Currency contracts | Other expense
Gains and losses on derivative instruments
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	1.4	1.3
Cash Flow Hedging [Member] | Variable-to-fixed cross-currency swaps | Interest expense
Gains and losses on derivative instruments
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	3.4	0.1
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	2.5	3.6
Cash Flow Hedging [Member] | Variable-to-fixed cross-currency swaps | Other expense
Gains and losses on derivative instruments
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	7.6	8.4
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	7.6	8.4
Derivatives not designated as hedging instruments under ASC 815: | Currency contracts | Other expense
Gains and losses on derivative instruments
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(1.9)	(0.1)
AOCI, Derivative Qualifying as Hedge, Excluded Component, Parent [Member] | Cash Flow Hedging [Member] | Currency contracts
Gains and losses on derivative instruments
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), before Adjustments and Tax	$ 1.1	$ 0

Fair Value Measurements and R_8

Fair Value Measurements and Risk- Cash Flow Hedges and Net Investment Hedges (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Interest and Debt Expense	$ (18,300,000)	$ (20,000,000)
Nonoperating Income (Expense)	8,800,000	2,200,000
Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	11,300,000	13,300,000
Net Investment Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0	0
Net Investment Hedging | Currency Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Net Investment Hedge, Gain (Loss), before Reclassification and Tax	6,100,000	3,800,000
Interest expense | Interest rate contracts | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	(200,000)	0
Interest expense | Variable-to-fixed cross-currency swaps | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	2,500,000	3,600,000
Interest expense | Currency contracts | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	0	0
Gain (Loss) from Components Excluded from Assessment of Cash Flow Hedge Effectiveness, Net	0	0
Other expense | Interest rate contracts | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	0	0
Other expense | Variable-to-fixed cross-currency swaps | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	7,600,000	8,400,000
Other expense | Currency contracts | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	1,400,000	1,300,000
Gain (Loss) from Components Excluded from Assessment of Cash Flow Hedge Effectiveness, Net	$ 700,000	$ 700,000

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Effective Income Tax Rate Reconciliation, Percent	27.20%	30.70%
Provision for (benefit from) income taxes	$ (15.7)	$ (10.9)
Deferred Tax Assets, Tax Credit Carryforwards, Gross of UTB	$ 302

Pension Plans and Other Postr_3

Pension Plans and Other Postretirement Benefit Plans - Pension Plans and Other Postretirement Benefit (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Funded status of fully funded, underfunded, and unfunded pension plans:
Overfunded defined benefit pension plans	$ 8.9		$ 8.5
Unfunded defined benefit pension plans	514.8		519.8
Pension liabilities included in other current liabilities	14.7		14.8
Net funded status	(520.6)		(526.1)
Underfunded Plan
Funded status of fully funded, underfunded, and unfunded pension plans:
Unfunded defined benefit pension plans	84.5		85.2
Unfunded Plan [Member]
Funded status of fully funded, underfunded, and unfunded pension plans:
Unfunded defined benefit pension plans	430.3		$ 434.6
Foreign Plan [Member]
Funded status of fully funded, underfunded, and unfunded pension plans:
Defined Benefit Plan, Service Cost	2.7	$ 2.2
Defined Benefit Plan, Interest Cost	1	1.3
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	(0.3)	(0.2)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	0	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	3.4	3.3
United States
Funded status of fully funded, underfunded, and unfunded pension plans:
Defined Benefit Plan, Service Cost	4.7	3.9
Defined Benefit Plan, Interest Cost	7.6	9.6
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	(12)	(12)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(0.2)	(0.2)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ 0.1	$ 1.3

Pension Plans and Other Postr_4

Pension Plans and Other Postretirement Benefit Plans - Components of Net Periodic Benefit Cost (Income) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Defined contribution retirement plan
Costs related to defined contribution retirement plan		$ 3.3
United States
Defined contribution retirement plan
Percentage that the employer contributes of employee contributions under 401(k) plan	100.00%
Maximum percentage of employee compensation match by employer to defined contribution plan	6.00%
Costs related to defined contribution retirement plan	$ 3.3
Enhanced Defined Contribution Plans [Member]
Defined contribution retirement plan
Costs related to defined contribution retirement plan	$ 1.2	$ 0.8
Enhanced Defined Contribution Plans [Member] | United States
Defined contribution retirement plan
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	4.00%

Other Balance Sheet Accounts (D

Other Balance Sheet Accounts (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Schedule of other assets and other liabilities [Line Items]
Current asset, related party	$ 184.7	$ 173.9
Nontrade Receivables, Current	21.6	24.1
Derivative Asset, Current	10.9	15.6
Income Taxes Receivable	9.5	4.2
Other Assets, Miscellaneous, Current	18.4	17.3
Other current assets	245.1	235.1
Other Current Liabilities
Current liability, related party	184.7	173.9
Employee-related Liabilities, Current	35.3	53.6
Deferred revenue (see Note 13)	34.8	35
Accrued interest (see Note 3)	26.4	13.3
Environmental contingencies (see Note 8)	18.7	17.8
Pension liabilities (see Note 6)	14.7	14.8
Income taxes payable (see Note 5)	11.5	8.6
Operating Lease, Liability, Current	8.9	9.3
Liability for dam spillway replacement, current	4.4	4.7
Other accrued liabilities	75.2	88.7
Total Other Current Liabilities	414.6	419.7
Other Liabilities, Noncurrent
Environmental contingencies (see Note 8)	94.1	97.5
Liability for dam spillway replacement	61	61.7
Deferred revenue (see Note 13)	30	29.5
Operating Lease, Liability, Noncurrent	25.4	26.2
Legacy Product Liability	24	24
Retained obligations of divested businesses	11.9	12.7
Asset retirement obligation	9.5	9.4
Deferred Income Tax Liabilities, Net	7.5	7.5
Derivative Liability, Noncurrent	4.2	13.2
Unrecognized Tax Benefits, Net of Deferred Taxes	4	4.1
Other noncurrent liabilities	22.2	22.4
Other Liabilities, Noncurrent	$ 293.8	$ 308.2

Commitments and Contingent Li_2

Commitments and Contingent Liabilities (Details) $ in Millions	3 Months Ended			12 Months Ended	36 Months Ended	74 Months Ended
	Mar. 31, 2020USD ($)paymentshares	Dec. 31, 2019USD ($)	Sep. 30, 2018USD ($)	Dec. 31, 2019USD ($)	Feb. 03, 2017USD ($)	Mar. 31, 2020USD ($)shares
Other Commitments [Abstract]
ZAI PD account funding					$ 49.4
ZAI P D account, maximum number of contingent deferred payments | payment	10
ZAI P D account, deferred payments, each year for twenty years	$ 8
Period in which ZAI PD contingent deferred payments will be made	20 years
Minimum ZAI P D account assets for condition in relation to contingent obligation payments	$ 10					$ 10
ZAI PD Claims and Expenses paid by the Trust						32
ZAI PD Attorney's fees paid by the Trust					$ 15
ZAI PD Trust Balance	$ 20					$ 20
Frequency of PD trust payments	6 months
Estimated annual expenses related to PD Trust	$ 0.2
Number of shares issuable under warrant (in shares) | shares	77,372,257					77,372,257
Period within which contingent funding obligations are reasonably estimable	5 years
Period Covered by Reserve for Loss Contingency	5 years
Legacy Matters
Accrual for Environmental Loss Contingencies	$ 112.8	$ 115.3		$ 115.3		$ 112.8
Legacy Product Charge		24
Remaining Period in Which ZAI PD Contingent Deferred Payments May be Made	19 years
Total Maximum Financial Obligation for ZAI PD Account Contingent Deferred Payments	$ 80
Maximum Annual Obligation for ZAI PD Account Contingent Deferred Payments	8
Non-Vermiculite Related Matters
Legacy Matters
Accrual for Environmental Loss Contingencies	38.9	39.3		39.3		38.9
Vermiculite Related Matters
Legacy Matters
Accrual for Environmental Loss Contingencies	73.9	$ 76		76		73.9
Operable Unit 3 [Member]
Legacy Matters
Environmental Remediation Expense			$ 70
Spillway [Member]
Legacy Matters
Loss Contingency, Loss in Period				$ 68
Minimum | Operable Unit 3 [Member]
Legacy Matters
Loss Contingency, Estimate of Possible Loss	30					30
Minimum | Spillway [Member]
Legacy Matters
Loss Contingency, Estimate of Possible Loss	$ 50					50
Site Contingency, Time Frame of Disbursements	three years
Maximum | Operable Unit 3 [Member]
Legacy Matters
Loss Contingency, Estimate of Possible Loss	$ 170					170
Maximum | Spillway [Member]
Legacy Matters
Loss Contingency, Estimate of Possible Loss	$ 100					100
Site Contingency, Time Frame of Disbursements	P4Y
ZAI PD Trust [Member] | Minimum
Legacy Matters
Loss Contingency, Estimate of Possible Loss	$ 16					16
ZAI PD Trust [Member] | Maximum
Legacy Matters
Loss Contingency, Estimate of Possible Loss	$ 24					$ 24

Commitments and Contingent Li_3

Commitments and Contingent Liabilities - Financial Assurances (Details) $ in Millions	Mar. 31, 2020USD ($)
Financial Guarantee
Financial assurances
Gross financial assurances issued and outstanding	$ 138.1
Surety Bonds
Financial assurances
Gross financial assurances issued and outstanding	68.9
Standby Letters of Credit
Financial assurances
Gross financial assurances issued and outstanding	$ 69.2

Restructuring Expenses and Re_3

Restructuring Expenses and Repositioning Expenses - Expenses and Asset Impairments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	$ 0.2	$ 1.1
Catalysts Technologies
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	0	0.2
Materials Technologies
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	0.2	1
Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	$ 0	$ (0.1)

Restructuring Expenses and Re_4

Restructuring Expenses and Repositioning Expenses - Liability Rollforward (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020USD ($)
Restructuring Reserve [Roll Forward]
Balance, December 31, 2019	$ 3.8
Accruals for severance and other costs	0.2
Payments	(1)
Balance, September 30, 2019	$ 3

Restructuring Expenses and Re_5

Restructuring Expenses and Repositioning Expenses - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Restructuring Cost and Reserve [Line Items]
Repositioning expenses	$ 2.5	$ 1.2

Other (Income) Expense, net (De

Other (Income) Expense, net (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Other Income and Expenses [Abstract]
Business interruption insurance recovery	$ 8	$ 8	$ 0
Net Periodic Defined Benefits Expense (Reversal of Expense), Excluding Service Cost Component	(3.9)		(1.5)
Third-party acquisition-related costs	1.5		0.3
Currency transaction effects	(0.9)		(0.2)
Net (gain) loss on sales of investments and disposals of assets	0.5		0.5
Other miscellaneous (income) expense	2		(1.3)
Total other (income) expense, net	$ (8.8)		$ (2.2)

Other Comprehensive Income (L_3

Other Comprehensive Income (Loss) - OCI Components (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Pre-Tax Amount	$ (0.1)	$ (0.1)
Tax Benefit/ (Expense)	0	0
After-Tax Amount	(0.1)	(0.1)
Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Pre-Tax Amount	3.9	12.9
Tax Benefit/ (Expense)	(1.4)	(1.2)
After-Tax Amount	2.5	11.7
Gain (Loss) from Hedging Activities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Pre-Tax Amount	(1.4)	(4.3)
Tax Benefit/ (Expense)	0.4	1.3
After-Tax Amount	(1)	(3)
Other comprehensive income (loss) attributable to W. R. Grace & Co. shareholders
Accumulated Other Comprehensive Income (Loss) [Line Items]
Pre-Tax Amount	2.4	8.5
Tax Benefit/ (Expense)	(1)	0.1
After-Tax Amount	$ 1.4	$ 8.6

Other Comprehensive Income (L_4

Other Comprehensive Income (Loss) - AOCI (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), Net of Tax	$ 1.4	$ 8.6
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	402.2	337
Ending balance	383.9	353.8
Defined Benefit Pension and Other Postretirement Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0.1	0.1
Other Comprehensive Income (Loss), Net of Tax	(0.1)	(0.1)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(0.5)	0.2
Ending balance	(0.6)	0.1
Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	2.5	11.7
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0
Other Comprehensive Income (Loss), Net of Tax	2.5	11.7
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	92.7	76.2
Ending balance	95.2	87.9
Gain (Loss) from Hedging Activities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	7.2	6.6
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	8.2	9.6
Other Comprehensive Income (Loss), Net of Tax	(1)	(3)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(13.4)	(8.5)
Ending balance	(14.4)	(11.5)
Other comprehensive income (loss) attributable to W. R. Grace & Co. shareholders
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	9.7	18.3
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	8.3	9.7
Other Comprehensive Income (Loss), Net of Tax	1.4	8.6
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	78.8	67.9
Ending balance	$ 80.2	$ 76.5

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Feb. 28, 2020	Feb. 08, 2017
Numerators
Net Income (Loss) Attributable to Parent	$ 42,000,000	$ 24,700,000
Denominators
Weighted average number of basic shares (in shares)	66,500,000	66,800,000
Dilutive effect of employee stock options (in shares)	0	100,000
Weighted average common shares—diluted calculation (in shares)	66,500,000	66,900,000
Basic earnings per share attributable to W. R. Grace & Co. shareholders
Net income (loss) (in dollars per share)	$ 0.63	$ 0.37
Diluted earnings per share attributable to W. R. Grace & Co. shareholders
Net income (loss) (in dollars per shares)	$ 0.63	$ 0.37
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive options outstanding (in shares)	1,700,000	900,000
Stock repurchase program, authorized amount			$ 250,000,000	$ 250,000,000
Stock repurchased during period (in shares)	673,807	69,860
Cash paid for repurchases of common stock	$ 40,400,000	$ 4,800,000
Stock repurchase program, remaining authorized repurchase amount	$ 235,000,000
2/8/2017 Share Repurchase Program [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock repurchase program, remaining authorized repurchase amount			$ 83,000,000

Revenues - Narrative (Details)

Revenues - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020USD ($)segment
Deferred Revenue Arrangement [Line Items]
Number of reportable segments | segment	2
Contract with customer, liability, revenue recognized in the period	$ 8.4
Contract With Customer Liability, Noncurrent, Recognition Period	5 years
Remaining performance obligation	$ 128

Revenues - Disaggregation of Re

Revenues - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Revenues	$ 421.5	$ 469.5
North America
Disaggregation of Revenue [Line Items]
Revenues	118.1	144.5
Europe Middle East Africa (EMEA)
Disaggregation of Revenue [Line Items]
Revenues	183.7	194.6
Asia Pacific
Disaggregation of Revenue [Line Items]
Revenues	100.3	109.2
Latin America
Disaggregation of Revenue [Line Items]
Revenues	19.4	21.2
Catalysts Technologies
Disaggregation of Revenue [Line Items]
Revenues	308	349.7
Catalysts Technologies | North America
Disaggregation of Revenue [Line Items]
Revenues	91	118
Catalysts Technologies | Europe Middle East Africa (EMEA)
Disaggregation of Revenue [Line Items]
Revenues	128.6	131.5
Catalysts Technologies | Asia Pacific
Disaggregation of Revenue [Line Items]
Revenues	78.1	88.1
Catalysts Technologies | Latin America
Disaggregation of Revenue [Line Items]
Revenues	10.3	12.1
Catalysts Technologies | Refining Catalysts
Disaggregation of Revenue [Line Items]
Revenues	168.6	181.8
Catalysts Technologies | Refining Catalysts | North America
Disaggregation of Revenue [Line Items]
Revenues	55.7	72.2
Catalysts Technologies | Refining Catalysts | Europe Middle East Africa (EMEA)
Disaggregation of Revenue [Line Items]
Revenues	75.9	66.6
Catalysts Technologies | Refining Catalysts | Asia Pacific
Disaggregation of Revenue [Line Items]
Revenues	31.5	35.7
Catalysts Technologies | Refining Catalysts | Latin America
Disaggregation of Revenue [Line Items]
Revenues	5.5	7.3
Catalysts Technologies | Polyolefin and Chemical Catalysts
Disaggregation of Revenue [Line Items]
Revenues	139.4	167.9
Catalysts Technologies | Polyolefin and Chemical Catalysts | North America
Disaggregation of Revenue [Line Items]
Revenues	35.3	45.8
Catalysts Technologies | Polyolefin and Chemical Catalysts | Europe Middle East Africa (EMEA)
Disaggregation of Revenue [Line Items]
Revenues	52.7	64.9
Catalysts Technologies | Polyolefin and Chemical Catalysts | Asia Pacific
Disaggregation of Revenue [Line Items]
Revenues	46.6	52.4
Catalysts Technologies | Polyolefin and Chemical Catalysts | Latin America
Disaggregation of Revenue [Line Items]
Revenues	4.8	4.8
Materials Technologies
Disaggregation of Revenue [Line Items]
Revenues	113.5	119.8
Materials Technologies | North America
Disaggregation of Revenue [Line Items]
Revenues	27.1	26.5
Materials Technologies | Europe Middle East Africa (EMEA)
Disaggregation of Revenue [Line Items]
Revenues	55.1	63.1
Materials Technologies | Asia Pacific
Disaggregation of Revenue [Line Items]
Revenues	22.2	21.1
Materials Technologies | Latin America
Disaggregation of Revenue [Line Items]
Revenues	9.1	9.1
Materials Technologies | Coatings
Disaggregation of Revenue [Line Items]
Revenues	36.6	38.2
Materials Technologies | Coatings | North America
Disaggregation of Revenue [Line Items]
Revenues	7.2	7
Materials Technologies | Coatings | Europe Middle East Africa (EMEA)
Disaggregation of Revenue [Line Items]
Revenues	18.4	19.7
Materials Technologies | Coatings | Asia Pacific
Disaggregation of Revenue [Line Items]
Revenues	8.6	9.4
Materials Technologies | Coatings | Latin America
Disaggregation of Revenue [Line Items]
Revenues	2.4	2.1
Materials Technologies | Consumer/Pharma
Disaggregation of Revenue [Line Items]
Revenues	33.5	37
Materials Technologies | Consumer/Pharma | North America
Disaggregation of Revenue [Line Items]
Revenues	10.3	9.3
Materials Technologies | Consumer/Pharma | Europe Middle East Africa (EMEA)
Disaggregation of Revenue [Line Items]
Revenues	13.6	19
Materials Technologies | Consumer/Pharma | Asia Pacific
Disaggregation of Revenue [Line Items]
Revenues	4.8	4
Materials Technologies | Consumer/Pharma | Latin America
Disaggregation of Revenue [Line Items]
Revenues	4.8	4.7
Materials Technologies | Chemical process
Disaggregation of Revenue [Line Items]
Revenues	37.8	38.9
Materials Technologies | Chemical process | North America
Disaggregation of Revenue [Line Items]
Revenues	8.2	9
Materials Technologies | Chemical process | Europe Middle East Africa (EMEA)
Disaggregation of Revenue [Line Items]
Revenues	19	19.9
Materials Technologies | Chemical process | Asia Pacific
Disaggregation of Revenue [Line Items]
Revenues	8.7	7.7
Materials Technologies | Chemical process | Latin America
Disaggregation of Revenue [Line Items]
Revenues	1.9	2.3
Materials Technologies | Other
Disaggregation of Revenue [Line Items]
Revenues	5.6	5.7
Materials Technologies | Other | North America
Disaggregation of Revenue [Line Items]
Revenues	1.4	1.2
Materials Technologies | Other | Europe Middle East Africa (EMEA)
Disaggregation of Revenue [Line Items]
Revenues	4.1	4.5
Materials Technologies | Other | Asia Pacific
Disaggregation of Revenue [Line Items]
Revenues	0.1	0
Materials Technologies | Other | Latin America
Disaggregation of Revenue [Line Items]
Revenues	$ 0	$ 0

Revenues - Contract with Custom

Revenues - Contract with Customers (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Revenues [Abstract]
Current	$ 34.8	$ 35
Noncurrent	30	29.5
Total	$ 64.8	$ 64.5

Revenues - Remaining Performanc

Revenues - Remaining Performance Obligations (Details)	Mar. 31, 2020
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	9 months
Approximate percentage of revenue related to remaining performance obligations recognized	20.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Approximate percentage of revenue related to remaining performance obligations recognized	29.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Approximate percentage of revenue related to remaining performance obligations recognized	22.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Approximate percentage of revenue related to remaining performance obligations recognized	15.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	4 years
Approximate percentage of revenue related to remaining performance obligations recognized	14.00%

Revenues Remaining Performance

Revenues Remaining Performance Obligation Total (Details)	3 Months Ended
	Mar. 31, 2020
Revenue , Remaining Performance Obligation Total [Abstract]
Contract With Customer Liability, Noncurrent, Recognition Period	5 years

Segment Information - Reportabl

Segment Information - Reportable Segment Data (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020USD ($)segment	Mar. 31, 2019USD ($)
Operating segment information
Number of reportable segments | segment	2
Net Sales
Revenues	$ 421.5	$ 469.5
Adjusted EBIT
Total	82.3	104.7
Reconciliation of operating segment data to financial statements
Costs related to legacy matters	(2.7)	(46.9)
Restructuring and repositioning expenses	(2.7)	(2.3)
Third-party acquisition-related costs	(1.5)	(0.3)
Taxes and interest included in equity in earnings of unconsolidated affiliate	0	(0.3)
Interest expense, net	(17.7)	(19.3)
Net Income (Loss) Attributable to Noncontrolling Interest	0.1	(0.1)
Income (loss) before income taxes	$ 57.8	35.5
Catalysts Technologies
Operating segment information
Number of reportable segments | segment	1
Number of operating segments | segment	2
Net Sales
Revenues	$ 308	349.7
Materials Technologies
Net Sales
Revenues	113.5	119.8
Corporate
Adjusted EBIT
Operating income	(15.6)	(16.2)
Certain pension costs	(3.1)	(4.8)
Operating Segments | Catalysts Technologies
Net Sales
Revenues	308	349.7
Adjusted EBIT
Operating income	82	101.7
Operating Segments | Materials Technologies
Net Sales
Revenues	113.5	119.8
Adjusted EBIT
Operating income	$ 19	$ 24

Segment Information - Geographi

Segment Information - Geographic Area Data (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Geographic Area Data
Revenues	$ 421.5	$ 469.5
United States
Geographic Area Data
Revenues	106.7	131.6
Canada
Geographic Area Data
Revenues	11.4	12.9
Total North America
Geographic Area Data
Revenues	118.1	144.5
Europe Middle East Africa
Geographic Area Data
Revenues	183.7	194.6
Asia Pacific
Geographic Area Data
Revenues	100.3	109.2
Latin America
Geographic Area Data
Revenues	$ 19.4	$ 21.2

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Equity Method Investments and Joint Ventures [Abstract]
Equity method investment ownership interest (percent)	50.00%
Investment in unconsolidated affiliate	$ 182,600,000		$ 181,900,000
Equity in earnings of unconsolidated affiliate	1,200,000	$ 4,100,000
ART's assets, liabilities and results of operations
Current assets	281,800,000		300,700,000
Noncurrent assets	249,500,000		237,800,000
Total assets	531,300,000		538,500,000
Current liabilities	168,500,000		177,100,000
Noncurrent liabilities	300,000		300,000
Total liabilities	168,800,000		177,400,000
Net sales	75,300,000	111,500,000
Costs and expenses applicable to net sales	68,000,000	97,300,000
Income before income taxes	2,900,000	9,700,000
Net income	2,500,000	9,200,000
Related Party Transactions [Abstract]
Product manufactured for ART	71,100,000	66,800,000
Mark-up on product manufactured for ART included as a reduction of Grace’s cost of goods sold	1,400,000	1,300,000
Charges for fixed costs; research and development; selling, general and administrative services; and depreciation to ART	14,100,000	12,800,000
Investment in unconsolidated affiliates
Operating Income Included in Income (Loss) from Equity Method Investments	1,600,000	3,900,000
Depreciation and Amortization Included in Income (Loss) From Equity Method Investments	(400,000)	(100,000)
Interest Expense and Income Taxes Included in Income (Loss) From Equity Method Investments	$ 0	300,000
Debt Instrument, Frequency of Periodic Payment	monthly
Loan Repayment Period, Max	P8Y
Current asset, related party	$ 184,700,000		173,900,000
Current liability, related party	184,700,000		173,900,000
Affiliated Entity [Member]
Investment in unconsolidated affiliates
Accounts receivable	1,800,000		3,600,000
Revenue from Related Parties	$ 1,900,000	$ 3,200,000
ART [Member]
Investment in unconsolidated affiliates
Basis spread on variable rate	1.25%
Accounts receivable	$ 19,500,000		17,500,000
Current asset, related party	184,700,000		173,900,000
Accounts payable	27,500,000		37,700,000
Debt payable within one year	9,800,000		9,900,000
Debt payable after one year	37,200,000		37,500,000
Current liability, related party	184,700,000		173,900,000
Grace LOC to ART [Member]
Investment in unconsolidated affiliates
Line of credit facility, maximum provided by Grace and Chevron each	$ 15,000,000
Commitment fee on credit facility (as a percent)	0.10%
Chevron
Investment in unconsolidated affiliates
Line of credit facility, maximum provided by Grace and Chevron each	$ 15,000,000
Commitment fee on credit facility (as a percent)	0.10%
Credit facility amount outstanding	$ 0		$ 0
Joint Venture [Member]
Investment in unconsolidated affiliates
Noncontrolling Interest, Ownership Percentage by Parent	87.50%