CONSOLIDATED CONDENSED STATEMENTS OF CHANGES IN SHAREDHOLDERS' EQUITY - USD ($) $ in Millions	Total	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest [Member]
Total shareholders' equity, beginning balance at Dec. 31, 2016	$ 1,428.4	$ 88.4	$ 1,789.2		$ 2.0
Postretirement benefit plans, beginning balance at Dec. 31, 2016				$ (145.2)
Cumulative translation adjustment, beginning balance at Dec. 31, 2016				(306.0)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Activity from stock incentive plans		0.4
Cumulative adjustment for accounting change (See Note 2)			0.5
Net income attributable to ITT Inc.	46.0		46.0
Dividends declared			(11.4)
Activity from stock incentive plans			10.5
Share repurchases		(0.1)	(2.2)
Net change in postretirement benefit plans	1.1			1.1
Net cumulative translation adjustment				19.2
Income (loss) attributable to noncontrolling interests	0.4				(0.4)
Other					0.0
Postretirement benefit plans, ending balance at Mar. 31, 2017				(144.1)
Cumulative translation adjustment, ending balance at Mar. 31, 2017				(286.8)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net change in common stock		0.3
Net change in retained earnings			43.4
Net change in accumulated other comprehensive loss				20.3
Net change in noncontrolling interests					(0.4)
Total shareholders' equity, ending balance at Mar. 31, 2017	1,492.0	88.7	1,832.6	(430.9)	1.6
Total shareholders' equity, beginning balance at Dec. 31, 2017	1,597.8	88.2	1,856.1		1.7
Postretirement benefit plans, beginning balance at Dec. 31, 2017				(137.6)
Cumulative translation adjustment, beginning balance at Dec. 31, 2017				(210.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Activity from stock incentive plans		0.3
Cumulative adjustment for accounting change (See Note 2)			(4.1)
Net income attributable to ITT Inc.	101.2		101.2
Dividends declared			(11.9)
Activity from stock incentive plans			4.7
Share repurchases		(1.1)	(54.2)
Net change in postretirement benefit plans	1.1			1.1
Net cumulative translation adjustment				26.5
Income (loss) attributable to noncontrolling interests	(0.1)				0.1
Other					0.1
Postretirement benefit plans, ending balance at Mar. 31, 2018				(136.5)
Cumulative translation adjustment, ending balance at Mar. 31, 2018				(184.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net change in common stock		(0.8)
Net change in retained earnings			35.7
Net change in accumulated other comprehensive loss				27.6
Net change in noncontrolling interests					0.2
Total shareholders' equity, ending balance at Mar. 31, 2018	$ 1,660.5	$ 87.4	$ 1,891.8	$ (320.6)	$ 1.9