Debt - Interest Expense and LT Debt Maturities (Details) $ in Millions |
Jun. 30, 2020
USD ($)
|
|---|---|
| Debt Instrument [Line Items] | |
| 2020 (July 1, 2020 to December 31, 2020) | $ 23,182 |
| 2021 | 29,415 |
| 2022 | 20,038 |
| 2023 | 22,339 |
| 2024 | 6,245 |
| 2025 | 8,805 |
| Thereafter | 17,194 |
| Total | 127,218 |
| Automotive [Member] | |
| Debt Instrument [Line Items] | |
| 2020 (July 1, 2020 to December 31, 2020) | 1,489 |
| 2021 | 1,908 |
| 2022 | 5,160 |
| 2023 | 13,010 |
| 2024 | 75 |
| 2025 | 2,540 |
| Thereafter | 11,253 |
| Total | 35,435 |
| GM Financial [Member] | |
| Debt Instrument [Line Items] | |
| 2020 (July 1, 2020 to December 31, 2020) | 21,693 |
| 2021 | 27,507 |
| 2022 | 14,878 |
| 2023 | 9,329 |
| 2024 | 6,170 |
| 2025 | 6,265 |
| Thereafter | 5,941 |
| Total | $ 91,783 |