Cash, Cash Equivalents, and Marketable Securities (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Items measured at fair value [Line Items]
Total cash and cash equivalents	$ 16,223	$ 15,905	$ 17,063	$ 14,272
Fair Value, Measurements, Recurring [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	1,893	2,254
Marketable securities	22,886	22,922
Fair Value, Estimate Not Practicable, Carrying (Reported) Amount [Member] | Investment Type [Member]
Items measured at fair value [Line Items]
Cash, time deposits, and money market funds	14,330	13,651
U.S. government | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	482	1,812
Marketable securities	6,342	9,733
U.S. government agencies | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	724	0
Marketable securities	4,340	2,749
Non-U.S. government and agencies | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	612	342
Marketable securities	6,826	5,383
Corporate debt | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	75	100
Marketable securities	5,138	4,804
Equities | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Items measured at fair value [Line Items]
Marketable securities	177	165
Other marketable securities | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Items measured at fair value [Line Items]
Marketable securities	63	88
Operating Segments [Member] | Automotive
Items measured at fair value [Line Items]
Total cash and cash equivalents	8,853	7,820
Operating Segments [Member] | Automotive | Fair Value, Measurements, Recurring [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	1,194	1,188
Marketable securities	19,575	19,642
Operating Segments [Member] | Automotive | Fair Value, Estimate Not Practicable, Carrying (Reported) Amount [Member] | Investment Type [Member]
Items measured at fair value [Line Items]
Cash, time deposits, and money market funds	7,659	6,632
Operating Segments [Member] | Automotive | U.S. government | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	300	888
Marketable securities	5,365	8,099
Operating Segments [Member] | Automotive | U.S. government agencies | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	624	0
Marketable securities	3,677	2,244
Operating Segments [Member] | Automotive | Non-U.S. government and agencies | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	270	200
Marketable securities	6,036	4,751
Operating Segments [Member] | Automotive | Corporate debt | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	0	100
Marketable securities	4,284	4,329
Operating Segments [Member] | Automotive | Equities | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Items measured at fair value [Line Items]
Marketable securities	177	165
Operating Segments [Member] | Automotive | Other marketable securities | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Items measured at fair value [Line Items]
Marketable securities	36	54
Operating Segments [Member] | Financial Services
Items measured at fair value [Line Items]
Total cash and cash equivalents	7,366	8,077
Operating Segments [Member] | Financial Services | Fair Value, Measurements, Recurring [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	699	1,066
Marketable securities	3,311	3,280
Operating Segments [Member] | Financial Services | Fair Value, Estimate Not Practicable, Carrying (Reported) Amount [Member] | Investment Type [Member]
Items measured at fair value [Line Items]
Cash, time deposits, and money market funds	6,667	7,011
Operating Segments [Member] | Financial Services | U.S. government | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	182	924
Marketable securities	977	1,634
Operating Segments [Member] | Financial Services | U.S. government agencies | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	100	0
Marketable securities	663	505
Operating Segments [Member] | Financial Services | Non-U.S. government and agencies | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	342	142
Marketable securities	790	632
Operating Segments [Member] | Financial Services | Corporate debt | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	75	0
Marketable securities	854	475
Operating Segments [Member] | Financial Services | Equities | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Items measured at fair value [Line Items]
Marketable securities		0
Operating Segments [Member] | Financial Services | Other marketable securities | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Items measured at fair value [Line Items]
Marketable securities	27	34
Operating Segments [Member] | All Other
Items measured at fair value [Line Items]
Total cash and cash equivalents	4	8
Operating Segments [Member] | All Other | Fair Value, Measurements, Recurring [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	0	0
Marketable securities	0	0
Operating Segments [Member] | All Other | Fair Value, Estimate Not Practicable, Carrying (Reported) Amount [Member] | Investment Type [Member]
Items measured at fair value [Line Items]
Cash, time deposits, and money market funds	4	8
Operating Segments [Member] | All Other | U.S. government | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	0	0
Marketable securities	0	0
Operating Segments [Member] | All Other | U.S. government agencies | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	0	0
Marketable securities	0	0
Operating Segments [Member] | All Other | Non-U.S. government and agencies | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	0	0
Marketable securities	0	0
Operating Segments [Member] | All Other | Corporate debt | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	0	0
Marketable securities	0	0
Operating Segments [Member] | All Other | Equities | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Items measured at fair value [Line Items]
Marketable securities	0	0
Operating Segments [Member] | All Other | Other marketable securities | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Items measured at fair value [Line Items]
Marketable securities	$ 0	$ 0