Restructuring Costs (Details) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended		22 Months Ended
	Mar. 31, 2017	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Jun. 30, 2017 USD ($)
Restructuring and Related Cost [Abstract]
Restructuring costs		$ 169	$ 139	$ 921	$ 300	$ 1,019
Employee Separation Charges [Roll Forward]
Liability balance at beginning of period				147	483	483
Increase in liability (separation charges)				506		297
Reduction in liability (payments)				(237)		(633)
Liability balance at end of period		416		416		147	$ 483	$ 416
September 2015 announcement
Restructuring and Related Cost [Abstract]
Restructuring costs				749		281	$ 569	1,599
Estimated restructuring costs		160		160				160
Discontinue production on-highway vocational trucks
Restructuring and Related Cost [Abstract]
Restructuring costs						104
Estimated restructuring costs		4		4				4
Q3 2016 announcement
Restructuring and Related Cost [Abstract]
Restructuring costs						$ 369
Gosselies closure announcement
Restructuring and Related Cost [Abstract]
Restructuring costs				667
Estimated restructuring costs		700		700				$ 700
Positions eliminated	2,000
Employee separations | Gosselies closure announcement
Restructuring and Related Cost [Abstract]
Restructuring costs				444
Employee separations | Other Operating Income (Expense)
Restructuring and Related Cost [Abstract]
Restructuring costs		42	45	506	76
Contract terminations | Other Operating Income (Expense)
Restructuring and Related Cost [Abstract]
Restructuring costs		17	36	26	46
Long-lived asset impairments | Gosselies closure announcement
Restructuring and Related Cost [Abstract]
Restructuring costs				199
Long-lived asset impairments | Other Operating Income (Expense)
Restructuring and Related Cost [Abstract]
Restructuring costs		63	14	275	96
Defined benefit retirement plan curtailments and termination benefits | Other Operating Income (Expense)
Restructuring and Related Cost [Abstract]
Restructuring costs				29	0
Other | Gosselies closure announcement
Restructuring and Related Cost [Abstract]
Restructuring costs				57
Other | Other Operating Income (Expense)
Restructuring and Related Cost [Abstract]
Restructuring costs		$ 47	$ 44	85	$ 82
LIFO inventory decrement benefit(expense) | Gosselies closure announcement
Restructuring and Related Cost [Abstract]
Restructuring costs				$ 33