An ideology is literally a structured ideal, systematically created as follows:

Ideologies may be based on religious, social, political, or economic grounds. In many cases, they're a combination of these elements. In practice, they tend to expand and become more complex as the practical issues related to the concept, principles, rules and laws become more involved.

Socialism- Started out as a particularly complex socio economic ideology, and devolved into a series of related but antagonistic ideologies: