What size wire to hookup a 100 amp panel for a detached shed 26 feet from main house 200 amp panel?

Fast answer? I assume this is 240V, 1-phase, (3)-#4 THWN cu + (1)-#8 ground...
Will this be underground? Be aware you need to keep your neutral bar in the panel isolated from the equipment ground and install a ground rod...

I don't like answering these simple "What size wire" questions. I am always afraid of all the other unanswered questions. The wire size is only one small part.

Agreed... I hope for additional contact by the poster.