Restructuring (Summary Of Changes To Restructuring-Related Liabilities) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2016			$ 4
Restructuring expense	$ (4)	$ (7)	(14)	$ (52)
Balance as of September 30, 2018	3		3
International
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2016			1
Balance as of September 30, 2018	1		1
International [Member]
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2016			3
Balance as of September 30, 2018	2		2
T17 Restructuring [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense			(2)
Payment for Restructuring			(4)
T17 Restructuring [Member] | International
Restructuring Reserve [Roll Forward]
Restructuring expense			(2)
Payment for Restructuring			(2)
T17 Restructuring [Member] | International [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense			0
Payment for Restructuring			(2)
Workforce Restructuring [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense			(9)
Payment for Restructuring			(8)
Workforce Restructuring [Member] | International
Restructuring Reserve [Roll Forward]
Restructuring expense			(2)
Payment for Restructuring			(2)
Workforce Restructuring [Member] | International [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense			(7)
Payment for Restructuring			(6)
2018 Truck Restructuring [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense			(2)
Payment for Restructuring			(2)
2018 Truck Restructuring [Member] | International
Restructuring Reserve [Roll Forward]
Restructuring expense			(2)
Payment for Restructuring			(2)
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 September 30, 2018	2		2
Personnel Related | T17 Restructuring [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense			0
Payment for Restructuring			(2)
Personnel Related | Workforce Restructuring [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense			(8)
Payment for Restructuring			(8)
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 September 30, 2018	$ 1		1
Other Restructuring [Member] | T17 Restructuring [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense			(2)
Payment for Restructuring			(2)
Other Restructuring [Member] | Workforce Restructuring [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense			(1)
Payment for Restructuring			0
Other Restructuring [Member] | 2018 Truck Restructuring [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense			(2)
Payment for Restructuring			$ (2)