Short-Term and Long-Term Debt Short and Long-Term Debt (Details) - USD ($) $ in Millions |
Jun. 30, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Automotive [Member] | ||
| Debt Instrument [Line Items] | ||
| Carrying amount | $ 9,187 | $ 9,410 |
| Fair Value | 9,292 | 9,799 |
| Automotive [Member] | Level 1 [Member] | ||
| Debt Instrument [Line Items] | ||
| Fair Value | 7,255 | 7,550 |
| Automotive [Member] | Level 2 [Member] | ||
| Debt Instrument [Line Items] | ||
| Fair Value | 2,037 | 2,249 |
| GM Financial [Member] | ||
| Debt Instrument [Line Items] | ||
| Carrying amount | 44,330 | 37,431 |
| Fair Value | 44,554 | 37,707 |
| GM Financial [Member] | Secured Debt [Member] | ||
| Debt Instrument [Line Items] | ||
| Carrying amount | 26,617 | 25,214 |
| Fair Value | 26,628 | 25,228 |
| GM Financial [Member] | Unsecured Debt [Member] | ||
| Debt Instrument [Line Items] | ||
| Carrying amount | 17,713 | 12,217 |
| Fair Value | 17,926 | 12,479 |
| GM Financial [Member] | Level 2 [Member] | ||
| Debt Instrument [Line Items] | ||
| Fair Value | 39,264 | 32,790 |
| GM Financial [Member] | Level 3 [Member] | ||
| Debt Instrument [Line Items] | ||
| Fair Value | $ 5,290 | $ 4,917 |