Design vs. engineering question

[Alaskan Son]

I'm assuming most of you guys are either designers, or builders (not architects or engineers or you would be using AutoDesk products). I'm a builder who is just getting into design work. I've been building off plans drawn on "napkins" or plans drawn by others for years now. I'm happy to say I'm changing that.

My question is, where do you draw the line between design and engineering?

I plan on pricing any necessary engineering as an allowance item, but I want to be fair with where I draw the line. Should I draw up foundation details, wall details etc. during the design process, or should this be something I let the engineer do? What about framing details?

I just think most details neither my subs nor myself need to see on plans. Its only local codes that require those details and ask for an engineers stamp, so in my mind I should only need to draw up the basics.

Any input as to how the rest of you handle this would be greatly appreciated. Thanks.