fuse lit on jpms $trillion interest rate swaps, page-22

These derivatives are little more than insurance policies and as the players spread their risks there is only an issue if one player backs the wrong side of too many.
The numbers are so large in much the same way as a few guys playing poker at home with matchsticks and agreeing each matchstick is worth a million dollars. So long as the game keeps going and no player wants to cash in and there is ample supply of matchsticks then there is no threat to economic markets.
No of the players have assets to back their exposure.