CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended
	Apr. 04, 2021	Mar. 29, 2020
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Consolidated net income	$ 41.0	$ 39.6
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	(28.9)	(43.1)
Pension and postretirement plan adjustments	2.5	2.1
Unrealized gains on cash flow hedges	4.9	1.8
Total other comprehensive (loss) income, net of tax	(21.5)	(39.2)
Total comprehensive income including non-controlling interests	19.5	0.4
Comprehensive income (loss) attributable to non-controlling interests	0.6	(0.3)
Comprehensive income attributable to Minerals Technologies Inc.	$ 18.9	$ 0.7