Steam Wirelessly from Laptop to TV

http://www.shopping.hp.com/en_US/home-office/-/products/Electronics/TV-Accessories/QE389AA;pgid=c7twGfjc0ptSRpIq7ZUcoGXQ00006n2wJSCz;sid=xAxATFHLmiFGRAF4I4Qc2IjE8BCFGWXXAVkRos3XztfN55e6STkXgKGk?HP-Wireless-TV-Connect-Kit
this product already offers a solution for this scenario. There are others like it, too.

As far as WIDI, i know your laptop needs to have WIDI, and AFAIK, most modern (2012+) intel-based laptops offer WIDI (you can tell by typing in "WIDI" in your run bar and something should pop up if you have it). And for the TV, i believe you can just use an adapter box; theres a list of compatible adapter boxes on this website:
http://www.intel.com/content/www/us/en/architecture-and-technology/intel-wireless-display.html

edit: and to clarify, i do not believe your TV needs to be wireless or even be internet enabled for WIDI to work, since the signal goes straight from your PC to the adapter box, which hooks up to your TV via HDMI and only sends a video signal.