This is a bug present in Chrome from version 36+. text-decoration not displayed during installation with :first-letter .
Chrome has an interesting history of rendering differences for text-decoration: underline compared to other browsers.
These examples have the first letter set to font-size: 10em; . I got screenshots from crossbrowsertesting.com .
You can view the full results in Chrome for OSX here and Windows 7 here.
Here you can view jsfiddle .
Firefox agreed
By comparison, Firefox has these consistent results verified since version 7 :

Internet explorer
Even IE is more consistent.
IE 6 - 7 IE8 + p>


Chrome is different
They come from Chrome running on Mac OS 10.9 and Windows 7 64bit.
Chrome Version 19 - Version 31
Single underline pixel

Chrome Version 32 - Version 33
Underlined image

Chrome Version 34 - Version 35
Windows 7 64bit Mac OSX


Chrome Version 36+
Error without underscore when installing with :first-letter .

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