Restructuring (Summary Of Changes To Restructuring-Related Liabilities) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2016	$ 4
Restructuring expense	(6)	$ (7)
Balance as of March 31, 2018	3
International
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2016	1
Balance as of March 31, 2018	0
International [Member]
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2016	3
Balance as of March 31, 2018	3
T17 Restructuring [Member]
Restructuring Reserve [Roll Forward]
Payment for Restructuring	(2)
T17 Restructuring [Member] | International
Restructuring Reserve [Roll Forward]
Payment for Restructuring	(1)
T17 Restructuring [Member] | International [Member]
Restructuring Reserve [Roll Forward]
Payment for Restructuring	(1)
Workforce Restructuring [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	(4)
Payment for Restructuring	(3)
Workforce Restructuring [Member] | International
Restructuring Reserve [Roll Forward]
Restructuring expense	(1)
Payment for Restructuring	(1)
Workforce Restructuring [Member] | International [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	(3)
Payment for Restructuring	(2)
2018 Truck Restructuring [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	(1)
Payment for Restructuring	(1)
2018 Truck Restructuring [Member] | International
Restructuring Reserve [Roll Forward]
Restructuring expense	(1)
Payment for Restructuring	(1)
2018 Truck Restructuring [Member] | International [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	0
Payment for Restructuring	0
Personnel Related
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2016	4
Balance as of March 31, 2018	3
Personnel Related | T17 Restructuring [Member]
Restructuring Reserve [Roll Forward]
Payment for Restructuring	(2)
Personnel Related | Workforce Restructuring [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	(4)
Payment for Restructuring	(3)
Personnel Related | 2018 Truck Restructuring [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	0
Payment for Restructuring	0
Other Restructuring [Member]
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2016	0
Balance as of March 31, 2018	0
Other Restructuring [Member] | T17 Restructuring [Member]
Restructuring Reserve [Roll Forward]
Payment for Restructuring	0
Other Restructuring [Member] | Workforce Restructuring [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	0
Payment for Restructuring	0
Other Restructuring [Member] | 2018 Truck Restructuring [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	(1)
Payment for Restructuring	$ (1)