Restructuring (Narrative) (Detail) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) Employee	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 4	$ 38	$ 10	$ 45
Restructuring Reserve	2		2		$ 4
Workforce Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			$ 7
Restructuring and Related Cost, Expected Number of Positions Eliminated | Employee			91
Restructuring and Related Cost, Number of Positions Eliminated | Employee			87
Restructuring and Related Cost, Expected Cost	11		$ 11
Payments for Restructuring			$ 6
T17 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Number of Positions Eliminated | Employee			673
Payments for Restructuring			$ 3
2018 Truck Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			2
Restructuring and Related Cost, Expected Cost	1		1
Payments for Restructuring			2
International [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	$ 2		2		$ 3
International [Member] | Workforce Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			5
Payments for Restructuring			4
International [Member] | T17 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			2
International [Member] | 2018 Truck Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			0
Payments for Restructuring			$ 0