IE thinks that float initial is float left?

IE thinks that float initial is float left?

I have the following html :
<div class="cleanContainer">
<div style="height:80px">test</div>
</div>
And this CSS :
.cleanContainer
{
float: left;
padding: 7px;
background-color: #ffffff;
width: 786px;
-moz-border-radius: 2px 2px 2px 2px;
-webkit-border-radius: 2px 2px 2px 2px;
border-radius: 2px 2px 2px 2px;
}
Then I got a @media screen CSS file where I got this :
.cleanContainer
{
float: initial;
padding: 3px;
width: auto;
}
This works fine in Chrome, the float is set to none and will take the
entire width. In IE it will be set as float: left and this is no good for
the design?
How do I solve this?