Restructuring and Other Related Charges (Summary Of Changes To Restructuring-Related Liabilities) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2021			$ 9
Restructuring expenses	$ 5	$ 17	47	$ 89
Balance as of September 30, 2021	5		5
Americas
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2021			3
Balance as of September 30, 2021	1		1
International
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2021			6
Balance as of September 30, 2021	4		4
T21
Restructuring Reserve [Roll Forward]
Restructuring expenses			16
Restructuring payment/utilization:			(15)
T21 | Americas
Restructuring Reserve [Roll Forward]
Restructuring expenses			3
Restructuring payment/utilization:			(3)
T21 | International
Restructuring Reserve [Roll Forward]
Restructuring expenses			13
Restructuring payment/utilization:			(12)
2020 Optimization Plan
Restructuring Reserve [Roll Forward]
Restructuring payment/utilization:			(5)
2020 Optimization Plan | Americas
Restructuring Reserve [Roll Forward]
Restructuring payment/utilization:			(2)
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, 2021			4
Balance as of September 30, 2021	1		1
Personnel | T21
Restructuring Reserve [Roll Forward]
Restructuring expenses			13
Restructuring payment/utilization:			(10)
Personnel | 2020 Optimization Plan
Restructuring Reserve [Roll Forward]
Restructuring payment/utilization:			(5)
Personnel | T19
Restructuring Reserve [Roll Forward]
Restructuring expenses			0
Restructuring payment/utilization:			(1)
Facility Related
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2021			2
Balance as of September 30, 2021	1		1
Facility Related | T21
Restructuring Reserve [Roll Forward]
Restructuring expenses			2
Restructuring payment/utilization:			(3)
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, 2021			3
Balance as of September 30, 2021	$ 3		3
Other | T21
Restructuring Reserve [Roll Forward]
Restructuring expenses			1
Restructuring payment/utilization:			(2)
Other | 2020 Optimization Plan
Restructuring Reserve [Roll Forward]
Restructuring payment/utilization:			0
Other | T19
Restructuring Reserve [Roll Forward]
Restructuring expenses			(2)
Restructuring payment/utilization:			$ 3