In "[The Diplomat's Club](http://seinfeldscripts.com/TheDiplomatClub.htm)" (*Seinfeld* Season 6 Episode 21) the phrase in question is used in the following context:

Kramer, one of the show's characters, is gambling with a stranger, and he's down by some amount. Kramer proposes a "double or nothing" final bet, which is accepted. Kramer ends up winning that bet... and it's later shown that he walks away *with a cheque*.

I don't get this. Given the definition of "[double or nothing](https://en.wikipedia.org/wiki/Double_or_nothing)", how is he walking away with anything at all? Isn't the idea that his previous debt should be merely cleared upon winning?