Business Restructuring Charges - Summary of Restructuring Accrual Activity (Detail) $ in Millions	3 Months Ended
	Dec. 31, 2020 USD ($)
CR Bard Inc
Restructuring Reserve [Roll Forward]
Balance at September 30, 2020	$ 16
Charged to expense	1
Cash payments	(4)
Balance at December 31, 2020	13
CR Bard Inc | Employee Termination
Restructuring Reserve [Roll Forward]
Balance at September 30, 2020	15
Charged to expense	0
Cash payments	(2)
Balance at December 31, 2020	13
CR Bard Inc | Other Restructuring
Restructuring Reserve [Roll Forward]
Balance at September 30, 2020	1
Charged to expense	1
Cash payments	(2)
Balance at December 31, 2020	0
Other Initiatives
Restructuring Reserve [Roll Forward]
Balance at September 30, 2020	20
Charged to expense	16
Cash payments	(20)
Balance at December 31, 2020	16
Other Initiatives | Employee Termination
Restructuring Reserve [Roll Forward]
Balance at September 30, 2020	17
Charged to expense	6
Cash payments	(10)
Balance at December 31, 2020	13
Other Initiatives | Other Restructuring
Restructuring Reserve [Roll Forward]
Balance at September 30, 2020	3
Charged to expense	10
Cash payments	(10)
Balance at December 31, 2020	$ 3