Derivative Instruments and Fair Value Measurements - Assets recorded at fair value on a nonrecurring basis (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Fair Value Measurements, Nonrecurring \| Finance group \| Unobservable Inputs Level 3
Assets measured at fair value on a nonrecurring basis
Impaired finance receivables, Balance	$ 26	$ 44

Impaired finance receivables fair value disclosure.

No definition available.

Name:	txt_ImpairedFinanceReceivablesFairValueDisclosure
Namespace Prefix:	txt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant