http://bugs.python.org/review/16036/diff/6073/Doc/library/functions.rst File Doc/library/functions.rst (right): http://bugs.python.org/review/16036/diff/6073/Doc/library/functions.rst#newcode637 Doc/library/functions.rst:637: For floating point numbers, this truncates towards zero. I don't know if it worth to mention specifically such details. Floating pointer numbers truncated first and then __int__() method called for result. http://bugs.python.org/review/16036/