Header Divider
The way to solve this without knowing the width and the background color is the following:
Structure
<div class="strike">
   <span>Kringle</span>
</div>
CSS
.strike {
    display: block;
    text-align: center;
    overflow: hidden;
    white-space: nowrap; 
}
.strike > span {
    position: relative;
    display: inline-block;
}
.strike > span:before,
.strike > span:after {
    content: "";
    position: absolute;
    top: 50%;
    width: 9999px;
    height: 1px;
    background: red;
}
.strike > span:before {
    right: 100%;
    margin-right: 15px;
}
.strike > span:after {
    left: 100%;
    margin-left: 15px;
}
Example: http://jsfiddle.net/z8Hnz/
Double line
To create a double line, use one of the following options:
1) Fixed space between lines
.strike > span:before,
.strike > span:after {
    content: "";
    position: absolute;
    top: 50%;
    width: 9999px;
    border-top: 4px double red;
Example: http://jsfiddle.net/z8Hnz/103/
2) Custom space between lines
.strike > span:before,
.strike > span:after {
    content: "";
    position: absolute;
    top: 50%;
    width: 9999px;
    height: 5px; /* space between lines */
    margin-top: -2px; /* adjust vertical align */
    border-top: 1px solid red;
    border-bottom: 1px solid red;
}
Example: http://jsfiddle.net/z8Hnz/105/
SASS (SCSS) version
Based on this solution, I added SCSS "with color property" if it could help someone...
//mixins.scss
@mixin bg-strike($color) {
    display: block;
    text-align: center;
    overflow: hidden;
    white-space: nowrap; 
    > span {
        position: relative;
        display: inline-block;
        &:before,
        &:after {
            content: "";
            position: absolute;
            top: 50%;
            width: 9999px;
            height: 1px;
            background: $color;
        }
        &:before {
            right: 100%;
            margin-right: 15px;
        }
        &:after {
            left: 100%;
            margin-left: 15px;
        }
    }
}
example of use :
//content.scss
h2 {
    @include bg-strike($col1);
    color: $col1;
}