Inventories (Details) - USD ($) $ in Millions |
Mar. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Inventory [Line Items] | ||
| Total productive material, supplies and work in process | $ 6,014 | $ 5,643 |
| Finished product, including service parts | 8,672 | 8,145 |
| Total inventories | 14,686 | 13,788 |
| GMNA [Member] | ||
| Inventory [Line Items] | ||
| Total productive material, supplies and work in process | 3,525 | 3,226 |
| Finished product, including service parts | 4,073 | 4,108 |
| Total inventories | 7,598 | 7,334 |
| GME [Member] | ||
| Inventory [Line Items] | ||
| Total productive material, supplies and work in process | 704 | 684 |
| Finished product, including service parts | 2,625 | 2,229 |
| Total inventories | 3,329 | 2,913 |
| GMIO [Member] | ||
| Inventory [Line Items] | ||
| Total productive material, supplies and work in process | 999 | 974 |
| Finished product, including service parts | 1,231 | 1,107 |
| Total inventories | 2,230 | 2,081 |
| GMSA [Member] | ||
| Inventory [Line Items] | ||
| Total productive material, supplies and work in process | 786 | 759 |
| Finished product, including service parts | 743 | 701 |
| Total inventories | $ 1,529 | $ 1,460 |