Password protected word docs only use 128 AES encryption. An improvement you could easily make is upping this encryption level to 256. Another suggestion you could also PGP encrypt the seed words inside the document itself.
I also think putting this information in a cloud environment would be sacrificing security. I assuming you are counting on google drive being around in the event of your hard-drive crashing. Unless you need this information on the go though I would think writing the information on a piece of paper and locking that away would be more secure, depending on your locations physical security.
You should also have multiple backup points in the event of a loss, even if you are counting on google drive being there you don't want that to be a single point of failure. I would suggest at least having one paper copy and possibly a thumb-drive/DVD copy.