It's simple Bory, the technology did not exist for either nation to try and launch an amphibious assault across 3,000 miles of ocean. The US wouldn't ignore Germany, a tentative peace would settle upon the world as neither nation would be able to deliver the knock out blow against the other and wars are very costly.
Here's a very polarized map of what I envision the world would be like. I toyed with the thought of listing neutrals too but in the end I voted to just list America and her allies (or nations whose politics are dominated by America) and Germany and her allies (or nations dominated by Germany.) As you can see I divided up Africa and Asia, let me explain. I divided Africa up by determining what nation they were a colony of. Southern Africa was almost entirely colonized by the Allies, the governments of Belgium, Britain, France and the Netherlands would operate in exile in their former colonies. The Germans would have continued the fight in Africa, but their armies could only stretch so far before they would be forced to stop less from Allied resistance but more from shear distance from their source of supplies. China would still go "red' in that the communist revolution would still take place but because of the German-occupied Russia to the north they would side with America. Japan, as I mention before, would be defeated, they are too far away from Germany for them to send much more than token assistance and as I have already mention, the US would have gone after Japan first instead of Europe. Southeast Asia would be shielded by India to the west and China to the north so German influence would be minimal. Governments of Britain and the Netherlands would retain a certain degree of control over these areas but India and the East Indies would be granted a certain degree of semi-autonomy.
Now, about this whole victory conditions, here's mine.
Germany wins if they expand no further than Russia, France and England. Even if everywhere they go they get slapped around like rag dolls they are victorious because they have conquered the largest empire in the history of mankind, regardless of whether the US remains or not.
The US wins by remaining independent and without losing any territories, simple as that.
As you can see, by my own victory conditions both nations can win. IMO the only problem with this outcome is that the Nazi's were the most evil sons of :cen:ches to ever walk the face of the earth and it would be far preferable if the world was united under one compassionate government, not one that survives by declaring group after group enemies of the state until everyone is dead.