When making a purchase at Walmart you are given $5 too much change. Do you say something or keep quiet ?

I was at a convenience store and the cashier gave me more money back than I had given for my purchase. I turned back to the counter and said I was given too much money. After it was sorted, another cashier thanked me for being so honest.
It doesn't matter where I'm shopping. I will still be honest and give the money back.