That would be a better question to ask a licensed CPA (Certified Public Accountant).
For most people, exactly zero of your Comcast bill is tax deductible. If you use your internet for business purposes, the exact percentage of your bill used exclusively for business purposes is generally deductible if you have a genuine business operation. If you use it for personal purposes, it will likely be disallowed by the IRS. You would need to keep extremely detailed records of your usage and be able to prove it was business use only to pass the sniff test.
For what it's worth, I have also looked at my Comcast bill and wondered how I can save, but I'm not good enough at keeping work records, and I bounce back and forth between work and personal Facebook (sshhh, secret). Not worth the audit risk to try and claim any part of it.