Cash, Cash Equivalents, and Marketable Securities (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Items measured at fair value [Line Items]
Total cash and cash equivalents	$ 17,589	$ 15,905	$ 13,340	$ 14,272
Fair Value, Measurements, Recurring [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	1,317	2,254
Marketable securities	20,492	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	16,272	13,651
U.S. government | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	610	1,812
Marketable securities	5,088	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	350	0
Marketable securities	3,374	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	357	342
Marketable securities	6,804	5,383
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	5,009	4,804
Equities | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Items measured at fair value [Line Items]
Marketable securities	160	165
Other marketable securities | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Items measured at fair value [Line Items]
Marketable securities	57	88
Operating Segments [Member] | Automotive
Items measured at fair value [Line Items]
Total cash and cash equivalents	8,753	7,820
Operating Segments [Member] | Automotive | Fair Value, Measurements, Recurring [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	648	1,188
Marketable securities	17,391	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	8,105	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	498	888
Marketable securities	4,418	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	150	0
Marketable securities	2,990	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	0	200
Marketable securities	5,833	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	3,958	4,329
Operating Segments [Member] | Automotive | Equities | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Items measured at fair value [Line Items]
Marketable securities	160	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	32	54
Operating Segments [Member] | Financial Services
Items measured at fair value [Line Items]
Total cash and cash equivalents	8,835	8,077
Operating Segments [Member] | Financial Services | Fair Value, Measurements, Recurring [Member]
Items measured at fair value [Line Items]
Cash and cash equivalents	669	1,066
Marketable securities	3,101	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	8,166	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	112	924
Marketable securities	670	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	200	0
Marketable securities	384	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	357	142
Marketable securities	971	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	0	0
Marketable securities	1,051	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	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	25	34
Operating Segments [Member] | All Other
Items measured at fair value [Line Items]
Total cash and cash equivalents	1	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	1	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