What word or phrase is best used to describe a monopoly in all economies - basically having a monopoly in everything.
For example, Company X has a monopoly in Food, Technology, Communication, Resources, etc.
Such a company could be called a Megacorporation. These companies are common in speculative fiction (some examples are Buy n Large from Wall-E, Mom-Corp from Futurama, and Blue Sun from Firefly), and used to exist in the past (such as the Dutch East India Company and the British East India Company), but basically cannot exist now due to competition law.
And while not monopolies, you may also like to look at the Japanese keiretsu and Korean chaebol. Massive conglomerates like the Mitsubishi Group are involved in industries including "Mining, shipbuilding, telecom, financial services, insurance, electronics, automotive, construction, heavy industries, oil and gas, real estate, foods and beverages, chemicals, steel, aviation and others" (Wikipedia).
You might say Company X had achieved both horizontal and vertical monopolies. See definitions of "vertical integration" and "horizontal integration".