Answer based on context:

In the United States Federal Budget for 2010, entitled 'A New Era of Responsibility', the DHS was allocated a discretionary budget of $42.7 billion . The end-of-yearDHS Annual Financial Report for financial year 2010 showed a net cost of operations of $56.4 billion , out of total budgetary resources of $83.2 billion . The components with the highest net cost were US Coast Guard , U.S. Customs and Border Protection , and Federal Emergency Management Agency . Revenues of $10.4 billion were generated in the year . According to the Washington Post, "DHS has given $31 billion in grants since 2003 to state and local governments for homeland security and to improve their ability to find and protect against terrorists, including $3.8 billion in 2010."

How many dollars (in billions) of the total budgetary resources were not spent on the net cost of operations?
26.8