Related Party Transactions - Receivables from and Payables to Affiliates (Detail) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Current receivables from affiliates:
Receivable from affiliates	$ 18.5	$ 4.5
Current payables to affiliates:
Payable to affiliates	18.8	27.6
Contran
Current receivables from affiliates:
Contran trade items	0.1	1.7
Current payables to affiliates:
Contran income taxes	1.5	8.3
Noncurrent payable to affiliates:
Contran - income taxes	44.5	50.4
LPC
Current receivables from affiliates:
Receivable from affiliates	15.8
Current payables to affiliates:
Payable to affiliates	17.3	19.3
VALHI, INC. | Contran | Credit Facility.
Noncurrent payable to affiliates:
Payables to affiliate included in long-term debt	172.9	270.7
Other Affiliates
Current receivables from affiliates:
Receivable from affiliates	$ 2.6	$ 2.8