While completing a grad school project, I was having a major headache! I was trying to insert an Excel spreadsheet with a lot of data into a word document. Every way I tried (thanks to Google), it came out wrong.  The margins were way off the page.  The spreadsheet only showed the first few rows.  It would insert as a picture and be so small that it couldn't be read.   It came to the point that I thought it was impossible! But, VIOLA!
I want to share with you what I did.  Maybe, it will be of use to you.  
- Save your Excel spreadsheet as a PDF.  Go to FILE>SAVE AS>under SAVE AS TYPE change to PDF.  Be sure to specify the name and location where you want to save it.
- Open PDF TO WORD ONLINE CONVERTER.  (I am in no way being compensated for sharing this site.  I simply found it in my struggle, and it is free!)
- Select CHOOSE FILE.  Find where you saved your PDF, and click to open it.
- Click CONVERT.  That's it! You will have to wait a few minutes depending on the size of your file, but it will open the file into a new word document.  You margins are perfect.  All the information is there.
- You can keep it as its own document, or choose to copy and paste it into another document.  This is what I did.  To do this:
- Highlight all the text in your newly converted document.  Press CTRL-C on your keyboard at the same time.  You don't have to hold them down.
- Open the document you want to insert the table into, and press CTRL-V to paste it into this document.  
There you go! Simple and headache free!
~Cara