Restructuring (Summary Of Changes To Restructuring-Related Liabilities) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2016	$ 2
Restructuring expense	(21)	$ (6)
Balance as of March 31, 2019	3
Americas
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2016	0
Balance as of March 31, 2019	0
International [Member]
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2016	2
Balance as of March 31, 2019	3
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	(18)
Payment for Restructuring	(16)
T19 Restructuring [Member] | Americas
Restructuring Reserve [Roll Forward]
Restructuring expense	(14)
Payment for Restructuring	(14)
T19 Restructuring [Member] | International [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	(4)
Payment for Restructuring	(2)
Personnel Related
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2016	1
Balance as of March 31, 2019	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	(8)
Payment for Restructuring	(7)
Other Restructuring [Member]
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2016	1
Balance as of March 31, 2019	2
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	(10)
Payment for Restructuring	$ (9)