The USA has been running the world financial system since the establishment of the IMF -(International Monetary Fund) and the World Bank which was created after the Bretton Woods agreement in 1945. See Bretton Woods System in Wikipedia
Now after years of US domination, at times bullying and financial irresponsibility of QE (Quantitative Easing ie printing fiat currency) the BRICS countries have had enough and they have set up a rival financial system that will be operational on 1st of October 2015. see Asian Infrastructure Investment Bank part of China’s bid for global clout also see the official AII website
The USA tried to stop its allies from signing the AII agreement but on June 27th 2015 – 57 Counties including Australia signed the agreement. see pictures
Larry Summers the former US Treasury Secretary said “This past month may be remembered as the moment the United States lost its role as the underwriter of the global economic system” Bloomberg April 6th see what Larry says on www.larrysummers.com
So after the 1st October 2015 we might see a significant shift in the value of the US dollar as it will NO LONGER be the world’s reserve currency.
It might be gradual decline or dramatic- no one really knows.