Off one's own bat

From Fresh Dictionary

English

Adverbial phrase

off one's own bat

1. ((idiomatic{{#if:|, {{{2}}}{{#if:|, {{{3}}}{{#if:|, {{{4}}}{{#if:|, {{{5}}}{{#if:|, {{{6}}}{{#if:|, {{{7}}}{{#if:|, {{{8}}}{{#if:|, {{{9}}}}}}}}}}}}}}}}}}})) At one's own instigation

   My boss didn't tell me to reorganize the filing system, I did it off my own bat