LIFO to FIFO Change in Accounting Principle - Income Statement (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 27, 2025	Sep. 28, 2024	Sep. 27, 2025	Sep. 28, 2024
Costs of revenue(a)	$ 643.9	$ 570.5	$ 1,866.2	$ 1,768.7
Gross profit	355.2	314.7	1,018.3	933.0
Operating Income (Loss)	179.8	208.6	505.8	518.2
Income from continuing operations before income tax	172.5	200.4	481.0	500.0
Income tax expense	44.3	38.0	122.0	104.1
Income from continuing operations	128.2	162.4	359.0	395.9
Net income	128.1	162.2	358.9	395.7
Net income attributable to ITT Inc.	126.9	161.6	356.3	392.9
Income from continuing operations	$ 127.0	$ 161.8	$ 356.4	$ 393.1
Discontinued operations		$ 0		$ 4.80
Basic earnings per share	$ 1.63	1.98	$ 4.49	4.80
Diluted		1.97		4.77
Diluted earnings per share	$ 1.62	$ 1.97	$ 4.46	$ 4.77
Previously Reported
Costs of revenue(a)		$ 571.2		$ 1,770.8
Gross profit		314.0		930.9
Operating Income (Loss)		207.9		516.1
Income from continuing operations before income tax		199.7		497.9
Income tax expense		37.8		103.6
Income from continuing operations		161.9		394.3
Net income		161.7		394.1
Net income attributable to ITT Inc.		161.1		391.3
Income from continuing operations		$ 161.3		$ 391.5
Discontinued operations		$ (0.01)		$ 4.78
Basic earnings per share		1.97		4.78
Diluted		1.96		4.75
Diluted earnings per share		$ 1.96		$ 4.75
Revision of Prior Period, Adjustment
Costs of revenue(a)		$ (0.7)		$ (2.1)
Gross profit		0.7		2.1
Operating Income (Loss)		0.7		2.1
Income from continuing operations before income tax		0.7		2.1
Income tax expense		0.2		0.5
Income from continuing operations		0.5		1.6
Net income		0.5		1.6
Net income attributable to ITT Inc.		0.5		1.6
Income from continuing operations		$ 0.5		$ 1.6
Discontinued operations		$ 10,000.00		$ 0.02
Basic earnings per share		0.01		0.02
Diluted		10,000.00		0.02
Diluted earnings per share		$ 10,000.00		$ 0.02