Xilinx calls main logic resource available on FPGA as CLB (Configurable Logic Block) whereas Altera call them LE (Logic Elements). Its just a matter of how they call it. Logically CLBs and LEs may be same but structurally they are different.
By terminology, CLBs are available on XILINX FPGAs and LEs are available on ALTERA FPGAs. Altera doesn't refer their logic block as CLB that's why you will not find the term CLB in Altera documents.