What do FM radios use as a detector?

Question

Please include as much information as possible.

Answer 1

Basically its a LC detector hooked to an antenna. When the resonant frequency of the LC tank is tuned to the receiving center freq, the signal is maximum and its output is demodulated to get audio output.

If this does not satisfy you, ask Google !

Answer 2

Are you asking about the process of demodulating the FM signal to produce an audio output?  

If so, here are some search terms to help you:

FM discriminator

Foster-Seeley discriminator

Ratio detector

Phase locked loop discriminator

Pulse integration detector

Slope detection of FM signal

Hope that helps.