Restructuring and Other Related Charges (Summary Of Changes To Restructuring-Related Liabilities) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2020			$ 9
Restructuring expenses	$ 22	$ 28	42	$ 72
Balance as of June 30, 2021	7		7
Americas
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2020			3
Balance as of June 30, 2021	2		2
International
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2020			6
Balance as of June 30, 2021	5		5
T21
Restructuring Reserve [Roll Forward]
Restructuring expenses			12
Restructuring (payment)/utilization			(10)
T21 | Americas
Restructuring Reserve [Roll Forward]
Restructuring expenses			2
Restructuring (payment)/utilization			(2)
T21 | International
Restructuring Reserve [Roll Forward]
Restructuring expenses			10
Restructuring (payment)/utilization			(8)
2020 Optimization Plan
Restructuring Reserve [Roll Forward]
Restructuring (payment)/utilization			(4)
2020 Optimization Plan | Americas
Restructuring Reserve [Roll Forward]
Restructuring (payment)/utilization			(1)
2020 Optimization Plan | International
Restructuring Reserve [Roll Forward]
Restructuring (payment)/utilization			(3)
T19
Restructuring Reserve [Roll Forward]
Restructuring expenses			(2)
Restructuring (payment)/utilization			(2)
T19 | Americas
Restructuring Reserve [Roll Forward]
Restructuring expenses			(2)
Restructuring (payment)/utilization			(2)
T19 | International
Restructuring Reserve [Roll Forward]
Restructuring expenses			0
Restructuring (payment)/utilization			0
Personnel
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2020			4
Balance as of June 30, 2021	3		3
Personnel | T21
Restructuring Reserve [Roll Forward]
Restructuring expenses			10
Restructuring (payment)/utilization			(7)
Personnel | 2020 Optimization Plan
Restructuring Reserve [Roll Forward]
Restructuring (payment)/utilization			(4)
Personnel | T19
Restructuring Reserve [Roll Forward]
Restructuring expenses			0
Restructuring (payment)/utilization			0
Facility Related
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2020			2
Balance as of June 30, 2021	2		2
Facility Related | T21
Restructuring Reserve [Roll Forward]
Restructuring expenses			2
Restructuring (payment)/utilization			(2)
Facility Related | 2020 Optimization Plan
Restructuring Reserve [Roll Forward]
Restructuring (payment)/utilization			0
Facility Related | T19
Restructuring Reserve [Roll Forward]
Restructuring expenses			0
Restructuring (payment)/utilization			0
Other
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2020			3
Balance as of June 30, 2021	$ 2		2
Other | T21
Restructuring Reserve [Roll Forward]
Restructuring expenses			0
Restructuring (payment)/utilization			(1)
Other | 2020 Optimization Plan
Restructuring Reserve [Roll Forward]
Restructuring (payment)/utilization			0
Other | T19
Restructuring Reserve [Roll Forward]
Restructuring expenses			(2)
Restructuring (payment)/utilization			$ (2)