Cash, Cash Equivalents, and Marketable Securities Available for Sale Securities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Sales proceeds	$ 5,753,000,000	$ 5,512,000,000	$ 3,315,000,000
Gross realized gains	13,000,000	1,000,000	3,000,000
Gross realized losses	10,000,000	21,000,000	8,000,000
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities	0	0	$ 0
Operating Segments | Automotive
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	13,468,000,000	12,911,000,000
Gross Unrealized Gains	87,000,000	12,000,000
Gross Unrealized Losses	(3,000,000)	(98,000,000)
Fair Value	13,552,000,000	12,825,000,000
Within 1 Year	5,241,000,000	3,854,000,000
After 1 Year through 5 Years	8,153,000,000	8,879,000,000
After 5 Years	158,000,000	92,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	1,104,000,000	2,674,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(2,000,000)	(19,000,000)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	854,000,000	6,534,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1,000,000)	(79,000,000)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,958,000,000	9,208,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(3,000,000)	(98,000,000)
Operating Segments | Automotive | U.S. government
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	2,839,000,000	2,933,000,000
Gross Unrealized Gains	11,000,000	5,000,000
Gross Unrealized Losses	(1,000,000)	(10,000,000)
Fair Value	2,849,000,000	2,928,000,000
Within 1 Year	1,028,000,000	1,714,000,000
After 1 Year through 5 Years	1,772,000,000	1,214,000,000
After 5 Years	49,000,000	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	183,000,000	199,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1,000,000)	(1,000,000)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	50,000,000	1,637,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	(9,000,000)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	233,000,000	1,836,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(1,000,000)	(10,000,000)
Operating Segments | Automotive | U.S. government agencies
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	1,445,000,000	1,920,000,000
Gross Unrealized Gains	2,000,000	0
Gross Unrealized Losses	(1,000,000)	(18,000,000)
Fair Value	1,446,000,000	1,902,000,000
Within 1 Year	830,000,000	797,000,000
After 1 Year through 5 Years	589,000,000	1,087,000,000
After 5 Years	27,000,000	18,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	370,000,000	193,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1,000,000)	(1,000,000)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	344,000,000	1,596,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	(17,000,000)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	714,000,000	1,789,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(1,000,000)	(18,000,000)
Operating Segments | Automotive | Non-U.S. government and agencies
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	3,925,000,000	3,841,000,000
Gross Unrealized Gains	20,000,000	4,000,000
Gross Unrealized Losses	(1,000,000)	(37,000,000)
Fair Value	3,944,000,000	3,808,000,000
Within 1 Year	1,546,000,000	194,000,000
After 1 Year through 5 Years	2,398,000,000	3,614,000,000
After 5 Years	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	463,000,000	341,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	(1,000,000)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	390,000,000	2,445,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1,000,000)	(36,000,000)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	853,000,000	2,786,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(1,000,000)	(37,000,000)
Operating Segments | Automotive | Corporate debt
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	5,029,000,000	4,010,000,000
Gross Unrealized Gains	53,000,000	3,000,000
Gross Unrealized Losses	0	(33,000,000)
Fair Value	5,082,000,000	3,980,000,000
Within 1 Year	1,837,000,000	1,148,000,000
After 1 Year through 5 Years	3,245,000,000	2,830,000,000
After 5 Years	0	2,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	29,000,000	1,816,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	(16,000,000)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	53,000,000	856,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	(17,000,000)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	82,000,000	2,672,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	0	(33,000,000)
Operating Segments | Automotive | Other marketable securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	230,000,000	207,000,000
Gross Unrealized Gains	1,000,000	0
Gross Unrealized Losses	0	0
Fair Value	231,000,000	207,000,000
Within 1 Year	0	1,000,000
After 1 Year through 5 Years	149,000,000	134,000,000
After 5 Years	82,000,000	72,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	59,000,000	125,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	17,000,000	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	76,000,000	125,000,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ 0	$ 0