Cash, Cash Equivalents, and Marketable Securities Available for Sale Securities (Details) - USD ($) | 3 Months Ended | |
Mar. 31, 2019 | Mar. 31, 2018 | Dec. 31, 2018 |
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] | | | |
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities | $ 0 | $ 0 | |
Proceeds from Sale of Debt Securities, Available-for-sale | 1,142,000,000 | 1,339,000,000 | |
Available-for-sale Securities, Gross Realized Gains | 2,000,000 | 0 | |
Available-for-sale Securities, Gross Realized Losses | 5,000,000 | $ 6,000,000 | |
Operating Segments [Member] | Automotive | | | |
Debt Securities, Available-for-sale [Line Items] | | | |
Available-for-sale Securities, Amortized Cost Basis | 13,891,000,000 | | $ 12,911,000,000 |
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax | 38,000,000 | | 12,000,000 |
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | 41,000,000 | | 98,000,000 |
Available-for-sale Securities | 13,888,000,000 | | 12,825,000,000 |
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value | 5,552,000,000 | | 3,854,000,000 |
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value | 8,240,000,000 | | 8,879,000,000 |
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Fair Value | 96,000,000 | | 92,000,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] | | | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value | 694,000,000 | | 2,674,000,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | (1,000,000) | | (19,000,000) |
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value | 5,538,000,000 | | 6,534,000,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | (40,000,000) | | (79,000,000) |
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value | 6,232,000,000 | | 9,208,000,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss | (41,000,000) | | (98,000,000) |
Operating Segments [Member] | Automotive | U.S. government | | | |
Debt Securities, Available-for-sale [Line Items] | | | |
Available-for-sale Securities, Amortized Cost Basis | 2,914,000,000 | | 2,933,000,000 |
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax | 7,000,000 | | 5,000,000 |
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | 5,000,000 | | 10,000,000 |
Available-for-sale Securities | 2,916,000,000 | | 2,928,000,000 |
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value | 1,884,000,000 | | 1,714,000,000 |
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value | 1,027,000,000 | | 1,214,000,000 |
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Fair Value | 5,000,000 | | 0 |
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] | | | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value | 324,000,000 | | 199,000,000 |
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 | 685,000,000 | | 1,637,000,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | (5,000,000) | | (9,000,000) |
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value | 1,009,000,000 | | 1,836,000,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss | (5,000,000) | | (10,000,000) |
Operating Segments [Member] | Automotive | U.S. government agencies | | | |
Debt Securities, Available-for-sale [Line Items] | | | |
Available-for-sale Securities, Amortized Cost Basis | 1,972,000,000 | | 1,920,000,000 |
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax | 1,000,000 | | 0 |
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | 10,000,000 | | 18,000,000 |
Available-for-sale Securities | 1,963,000,000 | | 1,902,000,000 |
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value | 1,106,000,000 | | 797,000,000 |
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value | 851,000,000 | | 1,087,000,000 |
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Fair Value | 6,000,000 | | 18,000,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] | | | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value | 90,000,000 | | 193,000,000 |
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 | 1,524,000,000 | | 1,596,000,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | (10,000,000) | | (17,000,000) |
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value | 1,614,000,000 | | 1,789,000,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss | (10,000,000) | | (18,000,000) |
Operating Segments [Member] | Automotive | Non-U.S. government and agencies | | | |
Debt Securities, Available-for-sale [Line Items] | | | |
Available-for-sale Securities, Amortized Cost Basis | 3,639,000,000 | | 3,841,000,000 |
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax | 8,000,000 | | 4,000,000 |
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | 17,000,000 | | 37,000,000 |
Available-for-sale Securities | 3,630,000,000 | | 3,808,000,000 |
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value | 362,000,000 | | 194,000,000 |
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value | 3,263,000,000 | | 3,614,000,000 |
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Fair Value | 5,000,000 | | 0 |
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] | | | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value | 25,000,000 | | 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 | 2,171,000,000 | | 2,445,000,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | (17,000,000) | | (36,000,000) |
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value | 2,196,000,000 | | 2,786,000,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss | (17,000,000) | | (37,000,000) |
Operating Segments [Member] | Automotive | Corporate debt | | | |
Debt Securities, Available-for-sale [Line Items] | | | |
Available-for-sale Securities, Amortized Cost Basis | 5,154,000,000 | | 4,010,000,000 |
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax | 21,000,000 | | 3,000,000 |
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | 9,000,000 | | 33,000,000 |
Available-for-sale Securities | 5,166,000,000 | | 3,980,000,000 |
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value | 2,199,000,000 | | 1,148,000,000 |
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value | 2,964,000,000 | | 2,830,000,000 |
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Fair Value | 3,000,000 | | 2,000,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] | | | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value | 233,000,000 | | 1,816,000,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | (1,000,000) | | (16,000,000) |
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value | 1,110,000,000 | | 856,000,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | (8,000,000) | | (17,000,000) |
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value | 1,343,000,000 | | 2,672,000,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss | (9,000,000) | | (33,000,000) |
Operating Segments [Member] | Automotive | Other marketable securities [Member] | | | |
Debt Securities, Available-for-sale [Line Items] | | | |
Available-for-sale Securities, Amortized Cost Basis | 212,000,000 | | 207,000,000 |
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax | 1,000,000 | | 0 |
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | 0 | | 0 |
Available-for-sale Securities | 213,000,000 | | 207,000,000 |
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value | 1,000,000 | | 1,000,000 |
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value | 135,000,000 | | 134,000,000 |
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Fair Value | 77,000,000 | | 72,000,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] | | | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value | 22,000,000 | | 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 | 48,000,000 | | 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 | 70,000,000 | | 125,000,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss | $ 0 | | $ 0 |