Business Restructuring Charges - Summary of Restructuring Accrual Activity (Detail) $ in Millions	3 Months Ended
	Dec. 31, 2019 USD ($)
CR Bard Inc
Restructuring Reserve [Roll Forward]
Balance at September 30, 2019	$ 23
Charged to expense	17
Cash payments	(13)
Non-cash settlements	(7)
Balance at December 31, 2019	20
CR Bard Inc | Employee Termination
Restructuring Reserve [Roll Forward]
Balance at September 30, 2019	22
Charged to expense	4
Cash payments	(7)
Non-cash settlements	0
Balance at December 31, 2019	19
CR Bard Inc | Other Restructuring
Restructuring Reserve [Roll Forward]
Balance at September 30, 2019	1
Charged to expense	13
Cash payments	(6)
Non-cash settlements	(7)
Balance at December 31, 2019	1
Other Initiatives
Restructuring Reserve [Roll Forward]
Balance at September 30, 2019	34
Charged to expense	6
Cash payments	(16)
Non-cash settlements	0
Balance at December 31, 2019	24
Other Initiatives | Employee Termination
Restructuring Reserve [Roll Forward]
Balance at September 30, 2019	31
Charged to expense	2
Cash payments	(12)
Non-cash settlements	0
Balance at December 31, 2019	21
Other Initiatives | Other Restructuring
Restructuring Reserve [Roll Forward]
Balance at September 30, 2019	3
Charged to expense	4
Cash payments	(4)
Non-cash settlements	0
Balance at December 31, 2019	$ 3