Inventories (Details) - USD ($) $ in Millions |
Mar. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Inventory [Line Items] | ||
| Total productive material, supplies and work in process | $ 6,134 | $ 5,147 |
| Finished product, including service parts | 9,683 | 8,617 |
| Total inventories | 15,817 | 13,764 |
| GMNA [Member] | ||
| Inventory [Line Items] | ||
| Total productive material, supplies and work in process | 3,407 | 2,705 |
| Finished product, including service parts | 5,379 | 4,884 |
| Total inventories | 8,786 | 7,589 |
| GME [Member] | ||
| Inventory [Line Items] | ||
| Total productive material, supplies and work in process | 782 | 713 |
| Finished product, including service parts | 2,641 | 2,166 |
| Total inventories | 3,423 | 2,879 |
| GMIO [Member] | ||
| Inventory [Line Items] | ||
| Total productive material, supplies and work in process | 1,158 | 1,113 |
| Finished product, including service parts | 1,110 | 954 |
| Total inventories | 2,268 | 2,067 |
| GMSA [Member] | ||
| Inventory [Line Items] | ||
| Total productive material, supplies and work in process | 787 | 616 |
| Finished product, including service parts | 553 | 613 |
| Total inventories | $ 1,340 | $ 1,229 |