Exclusive: Trump administration has found only $20 million in existing funds for wall - document

President Donald Trump’s promise to use existing funds to begin immediate construction of a wall on the U.S.-Mexico border has hit a financial roadblock, according to a document seen by Reuters.The rapid start of construction, promised throughout Trump's campaign and in an executive order issued in January on border security, was to be financed, according to the White House, with "existing funds and resources" of the Department of Homeland Security.The document said the funds would be enou