COMMITMENTS AND CONTINGENCIES Rollforward of Environmental Liability and Related Assets (Detail) - Liability [Member] - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Loss Contingency Accrual [Roll Forward]
Environmental liability - Beginning balance	$ 73.9	$ 76.6
Accruals added during the period for new matters	2.0	0.0
Net Cash Activity	(10.0)	(3.4)
Environmental liability - Ending balance	68.5	72.5
Continuing Operations [Member]
Loss Contingency Accrual [Roll Forward]
Changes In Pre-Existing Environmental Accruals	$ 2.6	$ (0.7)

Changes In Pre-Existing Environmental Accruals

No definition available.

Name:	itt_ChangesInPreExistingEnvironmentalAccruals
Namespace Prefix:	itt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Total costs accrued as of the balance sheet date for environmental loss contingencies.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14326-108349

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 30
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13207-110859

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 25
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6395460&loc=d3e13647-108346

+ Details

Name:	us-gaap_AccrualForEnvironmentalLossContingencies
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of expense for newly incurred environmental loss contingencies. Includes, but is not limited to, remediation expense and interest accretion.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 5.Y.Q2)
-URI http://asc.fasb.org/extlink&oid=27011672&loc=d3e149879-122751

+ Details

Name:	us-gaap_AccrualForEnvironmentalLossContingenciesChargesToExpenseForNewLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of cash outflow to settle environmental loss contingencies.

+ References

+ Details

Name:	us-gaap_AccrualForEnvironmentalLossContingenciesPayments1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

Name:	us-gaap_LossContingencyAccrualRollForward
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_LiabilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_SegmentContinuingOperationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: