Benefit Plans - Postemployment Benefit Costs (Detail) - USD ($) $ in Millions	12 Months Ended
Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Compensation and Retirement Disclosure [Abstract]
Service cost	$ 23	$ 18	$ 20
Interest cost	4	6	7
Amortization of prior service credit	0	(2)	(2)
Amortization of loss	13	18	21
Net postemployment benefit cost	$ 40	$ 42	$ 47

The amount of the prior service cost or credit recognized in net periodic postemployment benefit cost relating to benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation.

No definition available.

Name:	bdx_PostEmploymentBenefitAmortizationOfPriorServiceCreditCost
Namespace Prefix:	bdx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration