Debt - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2019
Debt Instrument [Line Items]
Short-term loans	$ 0
Long-term Debt, Weighted Average Interest Rate, at Point in Time	0.71%
Long-term Debt, Maturities, Repayments of Principal in Next Rolling Twelve Months	$ 2,500,000
ITT 2014 Revolving Credit Agreement [Member]
Debt Instrument [Line Items]
Revolving credit facility	500,000,000
Maximum face amount outstanding on letters of credit	100,000,000
Minimum amount of reduce commitments	10,000,000
Maximum potential increase in credit facility	200,000,000
Maximum potential credit facility outstanding	$ 700,000,000
Maximum Leverage Ratio Under Credit Facility	3.00
Minimum leverage ratio under credit facility	1.00
Maximum interest coverage ratio under credit facility	3.00
Minimum interest coverage ratio under credit facility	1.00
364 Day Revolving Credit Agreement [Member]
Debt Instrument [Line Items]
Revolving credit facility	$ 200
Line of Credit Facility, Interest Rate Description	1.55
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.35%
Commercial Paper [Member]
Debt Instrument [Line Items]
Short-term Debt, Weighted Average Interest Rate, at Point in Time	(0.06%)	0.05%