It boosted the US economy. Because of the destruction of a lot of the big cities in Europe, its economy was at rock bottom. Therefore Europe was economically dependent on the USA. This monetary and economical support from the USA to Europe was set up through 'the Marshall Plan' or the 'European Recovery Program (ERP)'.
This (temporary) expansion of the US market boosted the US economy (and stopped the spread of communism in Europe at the same time.).
