Yes, generally all engines are measured in litres. These numbers are usually rounded. So for example, an engine with 1960 cubic centimetres is rounded to 2.0 litres.
The "L" and "T" designations are not either/or though. Adding the "T" is just shorthand for saying that the engine is turbocharged. A 2.0T is still a 2.0L engine, if that makes sense. The L is usually implied, so if you describe an engine as being a 3.0 V6, that means it's a 3.0 litre engine.