All conforming DCC decoders meet an NMRA spec for control signal and track power. Any DCC throttle should be able to control any DCC decoder. However, the throttle bus and communications between controllers is proprietary. Therefore, DCC controllers from different manufacturers will not interoperate with each other.
DCC decoders are made by a number of manufacturers, including the makers of DCC systems. The big names in DCC controller systems in the US are: Digitrax, Lenz, NCE, CVP, MRC, and Bachmann (in no specific order).
Marklin and some other HO European manufacturers have put out proprietary digital command control systems that are NOT compatible with DCC, but they are seldom seen in the US.
MTH has made an HO locomotive that is compatible with DCS 3.0 and DCC. However, it is just the one locomotive to date. No DCS 3.0 decoders have been made available for separate sale.