|Yes it will be safe. You can never have too many watts. The thing to be wary of if Volts. Too many of them and the smoke escapes.|
Watts is a measurement of power. It is like saying my motors car is 100 Horsepower. Is it to powerful to drive down a country lane. Only if you press to hard on the accelerator. The laptop will sets its own level as far a power is concerned, it will take what it needs.
The Volts required is usually very specific. That should be a near as possible exactly what the specifications call for.
You also need to be looking at the Amps the power supply can supply as well as the Amps the laptop needs.
Watts = Volts * Amps