Password protect an excel document

Good evening to all.I'm in the process of downloading some bank statements that are in a spreadsheet format.Now my issue is will the microsoft office method be sufficient to password protect the excel file.
I'm using microsoft office 2010 on windows 7 home premium.Been looking on the good old google and came across the office method.
Would this method be okay and password strong enough to save the excel file Please ??.
Many thanks.
Found this on google.
Password protect a workbook - Excel

It's pretty good but there are also other easy methods. For example you can use 7-Zip to save the document in a compressed file and encrypt it with a password. It's encrypted with AES-256. If you use the default format .7z instead of .zip you can also encrypt the file names inside the archive.

Office 2010 uses AES-128

If you use both methods, even better. If you have separate password for the document and the zip, much better.

A general advice I practice myself when it comes to important passwords like encryption ones, is to use at least 20 characters and it should not be a word or phrase that can be found in dictionaries or similar. Why I recommend 20 chars is that it's usually too long to be used in brute force cracking.

Perhaps overkill for this issue but now you know what I think