There is a [technical article from Esri][1] that describes showing the codes in the attribute table instead of the domain text descriptions. 
[![domain descriptions][2]][2]
becomes
[![domain codes][3]][3]

 Try:

*Customize > ArcMap Options > Tables*

Then, uncheck the '*Display coded value domain and subtype descriptions*' option.


  [1]: https://support.esri.com/en/technical-article/000012200
  [2]: https://i.sstatic.net/4jnj0.gif
  [3]: https://i.sstatic.net/vAqL2.gif