Kind of dystopic, but I think this is a worst case scenario, honestly:
With no Marshall Plan, expect communism to spread like wildfire in Europe. In Italy, the Communists will probably win the 1948 general election. When the allies withdraw from Germany, expect a Soviet-backed 'war of liberation' to break the FRG (if it even exists) early on. Berlin becomes the capital of a unified DDR.
France's Communist Party will probably do markedly better as well. If the powers that be deny them a victory at the polls, you might see civil war or something in the aftermath. Austria probably goes red as well. The remaining noncommunist states probably form some sort of alliance without the United States (UK, Benelux nations, Norway, Denmark, Spain, Canada, Australia, South Africa, New Zealand), but they're grossly outnumbered by Red Europe.
In Asia, Chinese Communists achieve total victory over the KMT. North Korea unifies the peninsula after a brief conflict. If the United States occupies Japan for as long as they did IOTL, don't expect many changes there, but if they simply set up a new Constitution and then let the Japanese have at it, there's a very real possibility that the Japanese Communists win out at the polls if the Americans don't rebuild the country.
If France goes red, expect it's colonies to get independence and probably go red as well. Same for other colonial powers that go Communist.
India and Israel forge alliances with the Soviet bloc, while the Arabs ally with the Anticommunist European bloc. Latin America probably faces a great deal of leftist upheaval as well. There may very well be a short war between the uber-Soviet bloc and the European bloc, and this would favor the uber-Communists, of course, supposing that the United States stays neutral.