Organization and Basis of Presentation	9 Months Ended
Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Basis of Presentation	Note 1 - Organization and basis of presentation: Organization - At September 30, 2018, Valhi, Inc. (NYSE: VHI) held approximately 50% of our outstanding common stock and a wholly-owned subsidiary of NL Industries, Inc. (NYSE: NL) held approximately 30% of our common stock, Valhi owned approximately 83% of NL’s outstanding common stock and a wholly-owned subsidiary of Contran Corporation held approximately 92% of Valhi’s outstanding common stock. All of Contran’s outstanding voting stock is held by a family trust established for the benefit of Lisa K. Simmons and Serena Simmons Connelly and their children, for which Ms. Simmons and Ms. Connelly are co-trustees, or is held directly by Ms. Simmons and Ms. Connelly or entities related to them. Consequently, Ms. Simmons and Ms. Connelly may be deemed to control Contran, Valhi, NL and us. 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, 2017 that we filed with the Securities and Exchange Commission (“SEC”) on March 12, 2018 (“2017 Annual Report”). In our opinion, we have made all necessary adjustments (which include only normal recurring adjustments other than the reversal of the deferred income tax asset valuation allowance recognized in the second quarter of 2017, as discussed in Note 11), 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, 2017 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, 2017) 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, 2018 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 2017 Consolidated Financial Statements contained in our 2017 Annual Report. 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.

Note 1 - Organization and basis of presentation:

Organization - At September 30, 2018, Valhi, Inc. (NYSE: VHI) held approximately 50% of our outstanding common stock and a wholly-owned subsidiary of NL Industries, Inc. (NYSE: NL) held approximately 30% of our common stock, Valhi owned approximately 83% of NL’s outstanding common stock and a wholly-owned subsidiary of Contran Corporation held approximately 92% of Valhi’s outstanding common stock. All of Contran’s outstanding voting stock is held by a family trust established for the benefit of Lisa K. Simmons and Serena Simmons Connelly and their children, for which Ms. Simmons and Ms. Connelly are co-trustees, or is held directly by Ms. Simmons and Ms. Connelly or entities related to them. Consequently, Ms. Simmons and Ms. Connelly may be deemed to control Contran, Valhi, NL and us.

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, 2017 that we filed with the Securities and Exchange Commission (“SEC”) on March 12, 2018 (“2017 Annual Report”). In our opinion, we have made all necessary adjustments (which include only normal recurring adjustments other than the reversal of the deferred income tax asset valuation allowance recognized in the second quarter of 2017, as discussed in Note 11), 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, 2017 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, 2017) 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, 2018 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 2017 Consolidated Financial Statements contained in our 2017 Annual Report.

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.