Restructuring (Summary Of Changes To Restructuring-Related Liabilities) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2016			$ 2
Restructuring expense	$ (23)	$ (4)	(44)	$ (10)
Balance as of June 30, 2019	7		7
Americas
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2016			0
Balance as of June 30, 2019	5		5
International [Member]
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2016			2
Balance as of June 30, 2019	2		2
Workforce Restructuring [Member]
Restructuring Reserve [Roll Forward]
Payment for Restructuring			(1)
Workforce Restructuring [Member] | Americas
Restructuring Reserve [Roll Forward]
Payment for Restructuring			0
Workforce Restructuring [Member] | International [Member]
Restructuring Reserve [Roll Forward]
Payment for Restructuring			(1)
T19 Restructuring [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense			(33)
Payment for Restructuring			(27)
T19 Restructuring [Member] | Americas
Restructuring Reserve [Roll Forward]
Restructuring expense			(25)
Payment for Restructuring			(20)
T19 Restructuring [Member] | International [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense			(8)
Payment for Restructuring			(7)
Personnel Related
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2016			1
Balance as of June 30, 2019	1		1
Personnel Related | Workforce Restructuring [Member]
Restructuring Reserve [Roll Forward]
Payment for Restructuring			(1)
Personnel Related | T19 Restructuring [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense			(13)
Payment for Restructuring			(12)
Other Restructuring [Member]
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2016			1
Balance as of June 30, 2019	$ 6		6
Other Restructuring [Member] | Workforce Restructuring [Member]
Restructuring Reserve [Roll Forward]
Payment for Restructuring			0
Other Restructuring [Member] | T19 Restructuring [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense			(20)
Payment for Restructuring			$ (15)