Department of Homeland Security 'Office of the Under Secretary for Management' Budget Overview (Fiscal Year 2018 Congressional Justification) [open pdf - 4MB]
From the Document: "For necessary expenses of the Office of the Under Secretary for Management for operations and support, as authorized by sections 103 and 701 through 705 of the Homeland Security Act of 2002 (6 U.S.C. 113; 6 U.S.C. 341 through 345), [$727,771,000] '$696,131,000', of which not to exceed $2,000 shall be for official reception and representation expenses, and of which $227,516,000 shall remain available until September 30, 2019."
U.S. Department of Homeland Security: https://www.dhs.gov/