Goodwill (details) - USD ($) $ in Millions |
Jun. 30, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Goodwill by segment | ||
| Goodwill | $ 3,588 | $ 3,573 |
| Reportable Segments [Member] | Business and International Insurance [Member] | ||
| Goodwill by segment | ||
| Goodwill | 2,454 | 2,439 |
| Reportable Segments [Member] | Bond & Specialty Insurance [Member] | ||
| Goodwill by segment | ||
| Goodwill | 496 | 496 |
| Reportable Segments [Member] | Personal Insurance [Member] | ||
| Goodwill by segment | ||
| Goodwill | 612 | 612 |
| Other [Member] | ||
| Goodwill by segment | ||
| Goodwill | $ 26 | $ 26 |