Generally, companies are broken down into four levels of hierarchy, the corporate, the division, the business unit and the product level. The overall plan of the company is designed at a corporate level. As part of this planning, each resource is allocated to each division of the company. Next, division level planning allocates resources to each business unit of the company. In addition, business unit planning designs a strategic plan for each business area, which determines each of the marketing objectives/goals, strategies and tactics, that have to be consistent with the overall strategic plan.
When I ask entrepreneurs and small business owners, it is not unusual for not having any marketing plan. I once read that Sir Richard Branson never had any marketing plan when he started the 1st Virgin business many years ago. In fact in one study of entrepreneurship (I couldn't recall the name of the study) was that as much as 50% of entrepreneurs and business owners don't have a business plan and marketing plan when they first started the business.