Accidentally charged iPhone with iPad charger?

The iPhone 5 charger and the iPad mini charger look exactly the same. I usually know which is which because I got the mini for Christmas so its charger is a bit whiter and cleaner, but this morning I wasn't paying attention and I accidentally charged the iPhone with the iPad charger. All I noticed was that it charged a LOT faster than with its own charger. Was it "too strong" for the iPhone? Or does it not matter

Not at all you can use any apple charger that goes into it correctly