Business Restructuring Charges - Summary of Restructuring Accrual Activity (Detail) $ in Millions	9 Months Ended
	Jun. 30, 2018 USD ($)
CR Bard Inc
Restructuring Reserve [Roll Forward]
Balance at September 30, 2017	$ 0
Charged to expense	244
Cash payments	(60)
Non-cash settlements	(118)
Balance at June 30, 2018	66
CR Bard Inc | Employee Termination
Restructuring Reserve [Roll Forward]
Balance at September 30, 2017	0
Charged to expense	126
Cash payments	(60)
Non-cash settlements	0
Balance at June 30, 2018	66
CR Bard Inc | Other Restructuring
Restructuring Reserve [Roll Forward]
Balance at September 30, 2017	0
Charged to expense	118
Cash payments	0
Non-cash settlements	(118)
Balance at June 30, 2018	0
CareFusion/Other Initiatives
Restructuring Reserve [Roll Forward]
Balance at September 30, 2017	55
Charged to expense	44
Cash payments	(63)
Non-cash settlements	0
Balance at June 30, 2018	36
CareFusion/Other Initiatives | Employee Termination
Restructuring Reserve [Roll Forward]
Balance at September 30, 2017	49
Charged to expense	30
Cash payments	(49)
Non-cash settlements	0
Balance at June 30, 2018	30
CareFusion/Other Initiatives | Other Restructuring
Restructuring Reserve [Roll Forward]
Balance at September 30, 2017	6
Charged to expense	14
Cash payments	(14)
Non-cash settlements	0
Balance at June 30, 2018	$ 6