CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 334.6	$ 113.3	$ 186.6
Other comprehensive (loss) income:
Net foreign currency translation adjustment	(33.3)	95.4	(36.0)
Net change in postretirement benefit plans, net of tax impacts of $(1.6), $(5.5), and $(6.9), respectively	6.0	7.6	8.5
Net change investment securities, net of tax impacts of $0.0, $0.0, and $0.0, respectively	0.0	0.0	0.3
Other comprehensive (loss) income	(27.3)	103.0	(27.2)
Comprehensive income	307.3	216.3	159.4
Less: Comprehensive income (loss) attributable to noncontrolling interests	0.9	(0.2)	0.5
Comprehensive income attributable to ITT Inc.	306.4	216.5	158.9
Disclosure of reclassification adjustments and other adjustments to postretirement benefit plans (See Note 16)
Amortization of prior service benefit, net of tax expense of $1.1, $1.8, and $2.1, respectively	(3.3)	(3.0)	(3.5)
Amortization of net actuarial loss, net of tax benefit of $(2.4), $(4.1), and $(4.4), respectively	7.4	7.9	8.0
Loss on plan curtailment, net of tax benefit of $0.0, $(1.4), and $0.0, respectively	0.0	(2.3)	0.0
Loss on plan settlement, net of tax benefit of $(0.4), $0.0, and $(4.7), respectively	1.3	0.0	8.0
Prior service cost, net of tax benefit of $0.1, $0.8, and $0.0, respectively	0.0	(1.3)	(0.4)
Net actuarial gain (loss), net of tax benefit (expense) of $0.2, $(2.6), and $0.1, respectively	(0.4)	4.6	(4.1)
Unrealized change from foreign currency translation	1.0	(2.9)	0.5
Net change in postretirement benefit plans, net of tax impacts of $(1.6), $(5.5), and $(6.9), respectively	6.0	7.6	8.5
Disclosure of reclassification adjustments to investment securities
Realized loss on investing securities, net of tax benefit of $0.0, $0.0, and $0.0, respectively	$ 0.0	$ 0.0	$ 0.3