Why it is impossible to divide Integer number in Haskell?

This code

(4 :: Integer) / 2

will lead to error:

  No instance for (Fractional Integer) arising from a use of ‘/’
    In the expression: (4 :: Integer) / 2
    In an equation for ‘it’: it = (4 :: Integer) / 2

Why?

I need to specify

fromIntegral(4 :: Integer) / 2

to get a result. But what if I need a real number and not 2.0?