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Significant Accounting Policies (Details) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Jan. 01, 2018
Cash Equivalents [Abstract] |  |  |  |
Maximum Maturity Period for Highly Liquid Securities | 90 days |  |  |
Pension and Other Postretirement Plans [Abstract] |  |  |  |
Percentage Recognized as Pension Expense in the First Year | 60.00% |  |  |
Percentage of Pension Expense Recognized in Each of the Next Four Years | 10.00% |  |  |
Subsequent Period Over Which Pension Return Adjustment Is Amortized | 4 years |  |  |
Percentage of Non-US Pension Benefit Obligation Related to Canada, United Kingdom and Germany | 92.00% |  |  |
Income Taxes [Abstract] |  |  |  |
Valuation Allowance Methodology Number Of Years Utilized | 3 years |  |  |
Minimum Percentage Threshold To Recognize The Tax Benefit For Uncertain Tax Positions | 50.00% |  |  |
Foreign Currency Transactions and Translation [Abstract] |  |  |  |
Foreign currency transaction and remeasurement losses | $ 52 | $ 229 | $ 806 |
Recently Adopted Accounting Standards and Accounting Standards Not Yet Adopted [Abstract] |  |  |  |
Operating Income (Loss) | 10,016 | 9,962 | 5,538 |
Automotive Selling, General and Administrative Expense [Member] |  |  |  |
Advertising and Promotion Expenditures [Abstract] |  |  |  |
Advertising and Promotion Expenditures | 4,300 | 4,600 | 4,400 |
Automotive Cost of Sales [Member] |  |  |  |
Research and Development Expenditures [Abstract] |  |  |  |
Research and Development Expenditures | $ 7,300 | 6,600 | $ 6,000 |
GM Financial [Member] | Minimum [Member] | Vehicles [Member] |  |  |  |
Equipment on Operating Leases, net [Abstract] |  |  |  |
Leasing Arrangements, Term of Contract | 2 years |  |  |
GM Financial [Member] | Maximum [Member] | Vehicles [Member] |  |  |  |
Equipment on Operating Leases, net [Abstract] |  |  |  |
Leasing Arrangements, Term of Contract | 5 years |  |  |
GM Financial [Member] | Retail Finance Receivables [Member] |  |  |  |
Revenue Recognition [Abstract] |  |  |  |
Period Past Due Threshold for Suspending Accrual of Finance Charge Income | 60 days |  |  |
Finance Receivables [Abstract] |  |  |  |
Period Past Due Threshold for Charge Off of Finance Receivables | 120 days |  |  |
GM Financial [Member] | Commercial Finance Receivables [Member] |  |  |  |
Revenue Recognition [Abstract] |  |  |  |
Period Past Due Threshold for Suspending Accrual of Finance Charge Income | 90 days |  |  |
Automotive [Member] | Vehicles [Member] |  |  |  |
Equipment on Operating Leases, net [Abstract] |  |  |  |
Leasing Arrangements, Term of Contract | 7 months |  |  |
Forecast [Member] | Accounting Standards Update 2014-09 [Member] | Maximum [Member] |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |
Cumulative Effect of New Accounting Principle in Period of Adoption |  |  |  | $ 1,000
Pro Forma [Member] | Accounting Standards Update 2017-07 [Member] |  |  |  |
Recently Adopted Accounting Standards and Accounting Standards Not Yet Adopted [Abstract] |  |  |  |
Operating Income (Loss) | $ (1,300) | $ (1,300) |  |

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