CSS width property

Hello,

I am new to this list and I am desperate for an answer to my question. 
Ideally, setting the width, margin-left and margin-right properties on a 
block-level element to auto would create a centered box that sizes to 
its contents. Instead, all browsers that I know of default the width to 
100% if it is not set explicitly, and only tables and floating elements 
size to their contents. Floating has its own problems though, and 
{display: table} doesn't work in MSIE/Win. Is there any reliable way to 
make an element size to its contents without resorting to floating? 
Thanks in advance.

Greetings,
Timo Frenay.