Net Property and Lease Commitments (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment, Net, by Type [Abstract]
Net property	$ 30,126	$ 27,616
Depreciation, Depletion and Amortization [Abstract]
Total	7,385	6,504	5,486
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	246	267
Liabilities settled	(11)	(5)
Revision to estimates	(7)	(16)
Ending balance	228	246	267
Operating Leases, Future Minimum Payments Due [Abstract]
Operating Leases, Future Minimum Payments, Due in next twelve months	268
Operating Leases, Future Minimum Payments, Due in two years	219
Operating Leases, Future Minimum Payments, Due in three years	158
Operating Leases, Future Minimum Payments, Due in four years	92
Operating Leases, Future Minimum Payments, Due in five years	63
Operating Leases, Future Minimum Payments, Due Thereafter	83
Operating Leases, Future Minimum Payments Due - Total	883
Operating Leases, Rent Expense, Net [Abstract]
Rental expense	524	516	510
Building [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	36 years
Machinery, equipment and other [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	14 years 6 months
Software [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Mainframe and client based software [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	8 years
Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	30 years
Automotive [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Net property	29,795	27,492
Depreciation, Depletion and Amortization [Abstract]
Depreciation and other amortization	2,092	2,110	1,794
Amortization of special tools	2,160	1,954	1,861
Total	4,252	4,064	3,655
Maintenance and rearrangement	1,523	1,422	1,352
Operating Leases, Future Minimum Payments Due [Abstract]
Operating Leases, Future Minimum Payments, Due in next twelve months	211
Operating Leases, Future Minimum Payments, Due in two years	166
Operating Leases, Future Minimum Payments, Due in three years	117
Operating Leases, Future Minimum Payments, Due in four years	70
Operating Leases, Future Minimum Payments, Due in five years	51
Operating Leases, Future Minimum Payments, Due Thereafter	64
Operating Leases, Future Minimum Payments Due - Total	679
Operating Leases, Rent Expense, Net [Abstract]
Rental expense	423	411	404
Automotive [Member] | Land [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Gross property	351	440
Automotive [Member] | Buildings and Land Improvements [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Gross property	10,601	10,325
Automotive [Member] | Machinery, equipment and other [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Gross property	33,381	34,830
Automotive [Member] | Software [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Gross property	2,122	2,069
Automotive [Member] | Construction in progress [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Gross property	1,719	2,110
Automotive [Member] | Land, plant and equipment and other [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Gross property	48,174	49,774
Accumulated depreciation	(29,134)	(31,476)
Net property	19,040	18,298
Automotive [Member] | Special tools, net of amortization [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Net property	10,755	9,194
Financial Services [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Net property	331	124
Depreciation, Depletion and Amortization [Abstract]
Total	3,133	2,440	1,831
Operating Leases, Future Minimum Payments Due [Abstract]
Operating Leases, Future Minimum Payments, Due in next twelve months	57
Operating Leases, Future Minimum Payments, Due in two years	53
Operating Leases, Future Minimum Payments, Due in three years	41
Operating Leases, Future Minimum Payments, Due in four years	22
Operating Leases, Future Minimum Payments, Due in five years	12
Operating Leases, Future Minimum Payments, Due Thereafter	19
Operating Leases, Future Minimum Payments Due - Total	204
Operating Leases, Rent Expense, Net [Abstract]
Rental expense	$ 101	$ 105	$ 106
Minimum [Member]
Property, Plant and Equipment [Line Items]
Capitalization useful life policy	more than one year
Property, Plant and Equipment, Useful Life	3 years
Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	36 years