Customers for Arizona’s largest utility will see some unexpected savings on their bills this year because of the GOP tax plan.

The cut in the corporate tax rate — a key part of the Republican’s tax overhaul — would amount to a decrease of $4.68 for the average Arizona Public Service customer. The $119 million in savings will offset the utility's recently approved rate hike, which authorized a revenue increase of $95 million.

The Arizona Corporation Commission still has to OK the decrease, which would appear as a credit on customers’ bills.

A statement from APS said it anticipates additional savings due to the tax bill but doesn’t have full details yet.

The change would take effect next month if regulators give their approval.