CONSOLIDATED CONDENSED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 02, 2021	Sep. 26, 2020	Oct. 02, 2021	Sep. 26, 2020
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 88.0	$ (46.3)	$ 213.7	$ 86.8
Other comprehensive (loss) income:
Net foreign currency translation adjustment	(21.5)	23.5	(43.1)	(25.7)
Net change in postretirement benefit plans, net of tax expense of $0.8, $0.6, $0.6, and $1.2, respectively	3.1	1.8	3.1	3.6
Other comprehensive (loss) income	(18.4)	25.3	(40.0)	(22.1)
Comprehensive income (loss)	69.6	(21.0)	173.7	64.7
Less: Comprehensive income attributable to noncontrolling interests	0.5	0.5	1.0	0.8
Comprehensive income (loss) attributable to ITT Inc.	69.1	(21.5)	172.7	63.9
Reclassification adjustments (see Note 15):
Amortization of prior service benefit, net of tax expense of $(0.2), $(0.3), $(0.8) and $(0.9), respectively	(0.7)	(1.0)	(2.6)	(2.9)
Amortization of net actuarial loss, net of tax benefit of $0.1, $0.6, $0.5 and $1.8, respectively	0.9	1.8	2.8	5.5
Net actuarial gain, net of tax expense of $0.9, $0.3, $0.9 and $0.3, respectively	2.9	1.0	2.9	1.0
Net change in postretirement benefit plans, net of tax expense of $0.8, $0.6, $0.6, and $1.2, respectively	$ 3.1	$ 1.8	$ 3.1	$ 3.6