You could use Float in conjunction with Con in the raster calculator and get your desired result in a single step. Good ol' raster algebra.
Here is an example using a 4 value integer (21, 41, 42, 43) raster that results in a float with the values of 1.0, 2.0, 3.0, 4.0.
Float(Con("nlcd" == 21, 1.0, Con("nlcd" == 41, 2.0, Con("nlcd" == 42, 3.0, Con("nlcd" == 43, 4.0, 0.0)))))
The 0.0 value at the end represents the value that is assigned to values in the integer raster that are not accounted for in the Con statement (the "else" clause). So, if I had an integer raster with the values "0, 5, 21, 41, 42, 43" that I applied the above statement to, the 0 and 5 would be assigned a value of 0.