Organization and Basis of Presentation (Policies)	9 Months Ended
Sep. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation	Basis of presentation - The unaudited Condensed Consolidated Financial Statements contained in this Quarterly Report have been prepared on the same basis as the audited Consolidated Financial Statements in our Annual Report on Form 10-K for the year ended December 31, 2019 that we filed with the Securities and Exchange Commission (SEC) on March 11, 2020 (2019 Annual Report). In our opinion, we have made all necessary adjustments (which include only normal recurring adjustments), in order to state fairly, in all material respects, our consolidated financial position, results of operations and cash flows as of the dates and for the periods presented. We have condensed the Consolidated Balance Sheet at December 31, 2019 contained in this Quarterly Report as compared to our audited Consolidated Financial Statements at that date, and we have omitted certain information and footnote disclosures (including those related to the Consolidated Balance Sheet at December 31, 2019) normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (GAAP). Our results of operations for the interim periods ended September 30, 2020, may not be indicative of our operating results for the full year. The Condensed Consolidated Financial Statements contained in this Quarterly Report should be read in conjunction with our 2019 Consolidated Financial Statements contained in our 2019 Annual Report. Our results of operations for the first nine months of 2020 were significantly impacted by the COVID-19 pandemic, primarily in the second and third quarters, specifically through reduced demand for many of our products resulting from the rapid contraction of vast areas of the global economy. The extent of the COVID-19 impact on our future operations will depend on the time period and degree to which the COVID-19 pandemic persists in the global economy thereby reducing customer demand for certain of our products, including the timing and extent to which our customers’ operations continue to be impacted, our customers’ perception as to when consumer demand for their products will return to pre-pandemic levels and on any future disruptions in our operations or our suppliers’ operations, all of which are difficult to predict. Unless otherwise indicated, references in this report to “we,” “us” or “our” refer to Kronos Worldwide, Inc. and its subsidiaries (NYSE: KRO) taken as a whole.
Marketable Securities	All of our marketable securities are accounted for as available-for-sale securities, which are carried at fair value using quoted market prices in active markets for each marketable security and represent a Level 1 input within the fair value hierarchy. Any unrealized gains or losses on the securities are recognized in Marketable equity securities on our Condensed Consolidated Statements of Income.
Commitments and Contingencies	We are involved in various environmental, contractual, product liability, patent (or intellectual property), employment and other claims and disputes incidental to our business. At least quarterly our management discusses and evaluates the status of any pending litigation to which we are a party. The factors considered in such evaluation include, among other things, the nature of such pending cases, the status of such pending cases, the advice of legal counsel and our experience in similar cases (if any). Based on such evaluation, we make a determination as to whether we believe (i) it is probable a loss has been incurred, and if so if the amount of such loss (or a range of loss) is reasonably estimable, or (ii) it is reasonably possible but not probable a loss has been incurred, and if so if the amount of such loss (or a range of loss) is reasonably estimable, or (iii) the probability a loss has been incurred is remote. We have not accrued any amounts for litigation matters because it is not reasonably possible we have incurred a loss that would be material to our consolidated financial condition, results of operations or liquidity.
Recent Accounting Pronouncement	In December 2019, the Financial Accounting Standards Board issued Accounting Standards Update (ASU) 2019-12, Simplifying the Accounting for Income Taxes, which changes the accounting for certain income tax transactions and reduces complexity in accounting for income taxes in certain areas. The ASU introduces new guidance including providing a policy election for an entity to not allocate consolidated current and deferred tax expense when a member of a consolidated tax return is not subject to income tax in its separate financial statements and is a disregarded entity by the taxing authority; and providing guidance to evaluate whether a step-up in tax basis of goodwill relates to a business combination in which book goodwill was recognized or a separate transaction. The ASU also changes existing guidance in a number of areas, including: the method of making an intraperiod allocation of total income tax expense if there is a loss in continuing operations and gains outside of continuing operations; determining when a deferred tax liability is recognized after an investor in a non-U.S. entity transitions to or from the equity method of accounting; accounting for tax law changes and year-to-date losses in interim periods; and determining how to apply the income tax guidance to franchise taxes that are partially based on income. We adopted this ASU as of January 1, 2020. The adoption of this ASU did not have a material effect on our Condensed Consolidated Financial Statements.

Organization and Basis of Presentation (Policies)

9 Months Ended

Sep. 30, 2020

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Basis of presentation - The unaudited Condensed Consolidated Financial Statements contained in this Quarterly Report have been prepared on the same basis as the audited Consolidated Financial Statements in our Annual Report on Form 10-K for the year ended December 31, 2019 that we filed with the Securities and Exchange Commission (SEC) on March 11, 2020 (2019 Annual Report). In our opinion, we have made all necessary adjustments (which include only normal recurring adjustments), in order to state fairly, in all material respects, our consolidated financial position, results of operations and cash flows as of the dates and for the periods presented. We have condensed the Consolidated Balance Sheet at December 31, 2019 contained in this Quarterly Report as compared to our audited Consolidated Financial Statements at that date, and we have omitted certain information and footnote disclosures (including those related to the Consolidated Balance Sheet at December 31, 2019) normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (GAAP). Our results of operations for the interim periods ended September 30, 2020, may not be indicative of our operating results for the full year. The Condensed Consolidated Financial Statements contained in this Quarterly Report should be read in conjunction with our 2019 Consolidated Financial Statements contained in our 2019 Annual Report.

Our results of operations for the first nine months of 2020 were significantly impacted by the COVID-19 pandemic, primarily in the second and third quarters, specifically through reduced demand for many of our products resulting from the rapid contraction of vast areas of the global economy. The extent of the COVID-19 impact on our future operations will depend on the time period and degree to which the COVID-19 pandemic persists in the global economy thereby reducing customer demand for certain of our products, including the timing and extent to which our customers’ operations continue to be impacted, our customers’ perception as to when consumer demand for their products will return to pre-pandemic levels and on any future disruptions in our operations or our suppliers’ operations, all of which are difficult to predict.

Unless otherwise indicated, references in this report to “we,” “us” or “our” refer to Kronos Worldwide, Inc. and its subsidiaries (NYSE: KRO) taken as a whole.

Marketable Securities

All of our marketable securities are accounted for as available-for-sale securities, which are carried at fair value using quoted market prices in active markets for each marketable security and represent a Level 1 input within the fair value hierarchy. Any unrealized gains or losses on the securities are recognized in Marketable equity securities on our Condensed Consolidated Statements of Income.

Commitments and Contingencies

We are involved in various environmental, contractual, product liability, patent (or intellectual property), employment and other claims and disputes incidental to our business. At least quarterly our management discusses and evaluates the status of any pending litigation to which we are a party. The factors considered in such evaluation include, among other things, the nature of such pending cases, the status of such pending cases, the advice of legal counsel and our experience in similar cases (if any). Based on such evaluation, we make a determination as to whether we believe (i) it is probable a loss has been incurred, and if so if the amount of such loss (or a range of loss) is reasonably estimable, or (ii) it is reasonably possible but not probable a loss has been incurred, and if so if the amount of such loss (or a range of loss) is reasonably estimable, or (iii) the probability a loss has been incurred is remote. We have not accrued any amounts for litigation matters because it is not reasonably possible we have incurred a loss that would be material to our consolidated financial condition, results of operations or liquidity.

Recent Accounting Pronouncement

In December 2019, the Financial Accounting Standards Board issued Accounting Standards Update (ASU) 2019-12, Simplifying the Accounting for Income Taxes, which changes the accounting for certain income tax transactions and reduces complexity in accounting for income taxes in certain areas. The ASU introduces new guidance including providing a policy election for an entity to not allocate consolidated current and deferred tax expense when a member of a consolidated tax return is not subject to income tax in its separate financial statements and is a disregarded entity by the taxing authority; and providing guidance to evaluate whether a step-up in tax basis of goodwill relates to a business combination in which book goodwill was recognized or a separate transaction. The ASU also changes existing guidance in a number of areas, including: the method of making an intraperiod allocation of total income tax expense if there is a loss in continuing operations and gains outside of continuing operations; determining when a deferred tax liability is recognized after an investor in a non-U.S. entity transitions to or from the equity method of accounting; accounting for tax law changes and year-to-date losses in interim periods; and determining how to apply the income tax guidance to franchise taxes that are partially based on income. We adopted this ASU as of January 1, 2020. The adoption of this ASU did not have a material effect on our Condensed Consolidated Financial Statements.