Summary of significant accounting policies - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022
Basis Of Presentation And Significant Accounting Policies [Line Items]
Shipping and handling costs	$ 438.6	$ 458.3
Chemicals
Basis Of Presentation And Significant Accounting Policies [Line Items]
Shipping and handling costs	$ 395.8	$ 413.9
Contran \| Valhi Incorporation
Basis Of Presentation And Significant Accounting Policies [Line Items]
Parent company ownership interest	92.00%

The aggregate costs related to goods produced and sold and services rendered by an entity during the reporting period. This excludes costs incurred during the reporting period related to financial services rendered and other revenue generating activities.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 924
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-URI https://asc.fasb.org/extlink&oid=6472922&loc=d3e499488-122856

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.2(a),(d))
-URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227

Name:	us-gaap_CostOfGoodsAndServicesSold
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration