Postretirement Benefit Plans - Additional Information (Detail) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) Participant shares	Dec. 31, 2014 USD ($)		Dec. 31, 2013 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Contributions made to pension plans	$ 18.4	$ 17.3		$ 15.3
Shares of ITT Stock Held in Defined Contribution Plan | shares	0.2
Active participants in numerous defined benefit pension plans | Participant	2,200
Amendments(a)	$ 0.0	54.2
Defined Benefit Plan, Reduction to Postretirement Liability from Plan Amendment and Curtailment		58.7
Accumulated benefit obligation	$ 415.4	$ 408.3
Long-term annual rate of return for domestic pension plans	8.00%	8.00%		8.00%
Increase to Benefit Obligation from Adoption of Revised Mortality Assumption		$ 19.0
Assumed rate of future decrease in per capita cost of health care for 2021	4.50%
Effect of one percent increase on benefit obligation	$ 6.6
Effect of one percent increase on annual service and interest cost components	0.2
Effect of one percent decrease on benefit obligation	5.6
Effect of one percent decrease on annual service and interest cost components	0.2
Contributions to postretirement plans	18.6	12.6		$ 11.9
Employer contributions	$ 18.6	12.6
Reduction to Investment Target Allocation for Fixed Income	15.00%
Expected Increase in NPPC due to lower expected return on assets	$ 2.0
Consolidated Hourly Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected Benefit Obligation	35.00%
Other Non Qualified Us Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected Benefit Obligation	11.00%
Pension Plan For Bargaining Unit Employees Seneca Falls [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected Benefit Obligation	35.00%
International Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected Benefit Obligation	19.00%
Amendments(a)	$ 0.0	0.0
Effect of curtailment / Special termination benefit	$ 0.1	$ 0.4		0.0
Long-term annual rate of return for domestic pension plans	4.80%	4.70%
Employer contributions	$ 3.8	$ 3.5
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Amendments(a)	0.0	58.7	[1]
Effect of curtailment / Special termination benefit	$ (4.2)	$ 0.0		0.0
Long-term annual rate of return for domestic pension plans	8.00%	8.00%
Defined Benefit Plan, Expected Employer Contributions Next Fiscal Year	$ 10.0
Employer contributions	6.2	$ 8.2
U.S. Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Amendments(a)	0.0	(4.5)
Effect of curtailment / Special termination benefit	$ 0.0	$ 0.0		1.2
Long-term annual rate of return for domestic pension plans	8.00%	8.00%
Employer contributions	$ 8.6	$ 0.9
Pre-age 65 retirees [Member]
Defined Benefit Plan Disclosure [Line Items]
Assumed rate of future increase in per capita cost of health care for 2013	8.50%
Post-age 65 retirees [Member]
Defined Benefit Plan Disclosure [Line Items]
Assumed rate of future increase in per capita cost of health care for 2013	6.50%
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect of curtailment / Special termination benefit	$ 0.1	0.4		$ 1.2
Contributions to postretirement plans	12.4	$ 4.4
Discretionary Pension Contribution	7.5
Defined Benefit Plan, Expected Employer Contributions Next Fiscal Year	$ 5.0

[1] (a)During 2014, management approved changes to certain other employee-related defined benefit plans, reducing certain retiree medical benefits, resulting in a decrease to ITT's other employee-related defined benefit liability of $58.7.