What’s the main idea in this paragraph I need 2 sentences please

The concept of the "suburbs" was built up by Levitt and Sons, and this concept had become extremely successful, as over  85% of new homes within the United States are in suburban areas- and is has become a staple of American culture.

..Well, you  might want to cut out the "staple of American culture" part. That's just me  talking out my butt.

.elections are held to determine who serves in congress.