I have an IRA that has $ from a 401K rollover, non-deductible contribs & gains. How is this treated if I withdraw $ since part of the $ have been taxed and part have not.

I have an IRA that includes money from a 401K rollover ($25K),  non-deductible contributions ($65K) and gains ($100K) for a total of $190K.  Also, I moved the account between brokers so the current broker does not have the full history.   If I were to withdraw $20K, how will this be reported since $65K has already been taxed?