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		0.5
Cumulative adjustment for accounting change (See Note 2)			0.5
Net income attributable to ITT Inc.	180.7		180.7
Dividends declared			(34.1)
Activity from stock incentive plans			20.2
Share repurchases		(0.9)	(32.0)
Net change in postretirement benefit plans	5.9			5.9
Net cumulative translation adjustment				84.4
Income (loss) attributable to noncontrolling interests	0.3				(0.3)
Other					(0.1)
Postretirement benefit plans, ending balance at Sep. 30, 2017				(139.3)
Cumulative translation adjustment, ending balance at Sep. 30, 2017				(221.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net change in common stock		(0.4)
Net change in retained earnings			135.3
Net change in accumulated other comprehensive loss				90.3
Net change in noncontrolling interests					(0.4)
Total shareholders' equity, ending balance at Sep. 30, 2017	1,653.2	88.0	1,924.5	(360.9)	1.6
Total shareholders' equity, beginning balance at Jun. 30, 2017	1,546.0	88.0	1,843.6		1.6
Postretirement benefit plans, beginning balance at Jun. 30, 2017				(142.9)
Cumulative translation adjustment, beginning balance at Jun. 30, 2017				(244.3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Activity from stock incentive plans		0.0
Cumulative adjustment for accounting change (See Note 2)			0.0
Net income attributable to ITT Inc.	86.9		86.9
Dividends declared			(11.3)
Activity from stock incentive plans			5.4
Share repurchases		0.0	(0.1)
Net change in postretirement benefit plans	3.6			3.6
Net cumulative translation adjustment				22.7
Income (loss) attributable to noncontrolling interests	0.0				0.0
Other					0.0
Postretirement benefit plans, ending balance at Sep. 30, 2017				(139.3)
Cumulative translation adjustment, ending balance at Sep. 30, 2017				(221.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net change in common stock		0.0
Net change in retained earnings			80.9
Net change in accumulated other comprehensive loss				26.3
Net change in noncontrolling interests					0.0
Total shareholders' equity, ending balance at Sep. 30, 2017	1,653.2	88.0	1,924.5	(360.9)	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		0.5
Cumulative adjustment for accounting change (See Note 2)			(4.1)
Net income attributable to ITT Inc.	281.8		281.8
Dividends declared			(35.6)
Activity from stock incentive plans			22.2
Share repurchases		(1.1)	(54.7)
Net change in postretirement benefit plans	6.1			6.1
Net cumulative translation adjustment				(25.6)
Income (loss) attributable to noncontrolling interests	(0.5)				0.5
Other					0.0
Postretirement benefit plans, ending balance at Sep. 30, 2018				(131.5)
Cumulative translation adjustment, ending balance at Sep. 30, 2018				(236.2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net change in common stock		(0.6)
Net change in retained earnings			209.6
Net change in accumulated other comprehensive loss				(19.5)
Net change in noncontrolling interests					0.5
Total shareholders' equity, ending balance at Sep. 30, 2018	1,787.8	87.6	2,065.7	(367.7)	2.2
Total shareholders' equity, beginning balance at Jun. 30, 2018	1,682.3	87.6	1,959.3		2.0
Postretirement benefit plans, beginning balance at Jun. 30, 2018				(135.4)
Cumulative translation adjustment, beginning balance at Jun. 30, 2018				(231.2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Activity from stock incentive plans		0.0
Cumulative adjustment for accounting change (See Note 2)			0.0
Net income attributable to ITT Inc.	110.9		110.9
Dividends declared			(11.9)
Activity from stock incentive plans			7.8
Share repurchases		0.0	(0.4)
Net change in postretirement benefit plans	3.9			3.9
Net cumulative translation adjustment				(5.0)
Income (loss) attributable to noncontrolling interests	(0.2)				0.2
Other					0.0
Postretirement benefit plans, ending balance at Sep. 30, 2018				(131.5)
Cumulative translation adjustment, ending balance at Sep. 30, 2018				(236.2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net change in common stock		0.0
Net change in retained earnings			106.4
Net change in accumulated other comprehensive loss				(1.1)
Net change in noncontrolling interests					0.2
Total shareholders' equity, ending balance at Sep. 30, 2018	$ 1,787.8	$ 87.6	$ 2,065.7	$ (367.7)	$ 2.2