T his report is part of a suite of reports that discuss appropriations for the Department of Homeland Security (DHS) for FY2017. It specifically discusses appropriations for the components of DHS included in the second title of the homeland security appropriations bill—Customs and Border Protection (CBP), Immigration and Customs Enforcement (ICE), the Transportation Security Administration (TSA), the U.S. Coast Guard (USCG), and the U.S. Secret Service (USSS). Collectively, Congress has labeled these components in recent years as "Security, Enforcement and Investigations." The report provides an overview of the Administration's FY2017 request for these components, and the appropriations proposed by the Senate and House appropriations committees in response. Rather than limiting the scope of its review to the first titles of the bills, the report includes information on provisions throughout the bills and reports that directly affect these components. The suite of CRS reports on homeland security appropriations tracks legislative action and congressional issues related to DHS appropriations, with particular attention paid to discretionary funding amounts. The reports do not provide in-depth analysis of specific issues related to mandatory funding—such as retirement pay—nor do they systematically follow other legislation related to the authorization or amending of DHS programs, activities, or fee revenues. Discussion of appropriations legislation involves a variety of specialized budgetary concepts. The Appendix to CRS Report R44621, Department of Homeland Security Appropriations: FY2017 , explains several of these concepts, including budget authority, obligations, outlays, discretionary and mandatory spending, offsetting collections, allocations, and adjustments to the discretionary spending caps under the Budget Control Act ( P.L. 112-25 ). A more complete discussion of those terms and the appropriations process in general can be found in CRS Report R42388, The Congressional Appropriations Process: An Introduction , by [author name scrubbed] and [author name scrubbed], and the Government Accountability Office's A Glossary of Terms Used in the Federal Budget Process . Note on Data and Citations Except in summary discussions and when discussing total amounts for the bill as a whole, all amounts contained in the suite of CRS reports on homeland security appropriations represent budget authority and are rounded to the nearest million. However, for precision in percentages and totals, all calculations were performed using unrounded data. Data used in this report for FY2016 amounts are derived from two sources. Normally, this report would rely on P.L. 114-113 , the Omnibus Appropriations Act, 2016—Division F of which is the Homeland Security Appropriations Act, 2016—and the accompanying explanatory statement published in Books II and III of the Congressional Record for December 17, 2015. However, due to the implementation of the Common Appropriations Structure for DHS (see below), additional information is drawn from H.Rept. 114-668 , which presents the FY2016 enacted funding in the new structure. H.Rept. 114-668 also serves as the primary source for the FY2016 enacted funding levels, the FY2017 Administration-requested funding levels, and the House Appropriations Committee recommendation in the new structure. S.Rept. 114-264 serves as the primary source for the FY2016 enacted funding levels, the FY2017 Administration-requested funding levels, and Senate Appropriations Committee recommendation in the "legacy structure"—the overall structure of appropriations enacted for FY2016. There are several differences of interpretation between the two committee reports in accounting for both the FY2016 enacted and FY2017 requested levels. These include differences in resources available for CBP through the Small Airport User Fee, how reimbursements for preclearance operations are accounted for, the size of the request for Immigration and Customs Enforcement salaries and expenses, and accounting for some TSA fees. To facilitate comparisons with the enacted and requested numbers, unless otherwise specified, this report relies on the data in S.Rept. 114-264 when the two reports are in conflict, as its interpretation of FY2016 enacted levels could be verified against the FY2016 explanatory statement. The "Common Appropriations Structure" Section 563 of Division F of P.L. 114-113 (the FY2016 Department of Homeland Security Appropriations Act) provided authority for DHS to submit its FY2017 appropriations request under the new common appropriations structure (CAS), and implement it in FY2017. Under the act, the new structure was to have four categories of appropriations: Operations and Support; Procurement, Construction, and Improvement; Research and Development; and Federal Assistance. Most of the FY2017 DHS appropriations request categorized its appropriations in this fashion. The exception was the Coast Guard, which was in the process of migrating its financial information to a new system. DHS has also proposed realigning its Programs, Project, and Activities (PPA) structure—the next level of funding detail below the appropriation level—possibly trying to align PPAs into a mission-based hierarchy. The House Appropriations Committee made its funding recommendation using the CAS (although it chose to implement it slightly differently than the Administration had envisioned in Title I), but the Senate Appropriations Committee did not, instead drafting its annual DHS appropriations bill and report using the same structure as was used in FY2016. It remains to be seen how differences between the House and Senate structures will be worked out in the legislation which finalizes FY2017 appropriations levels for DHS. Some individual programmatic comparisons are possible between the two bills, and the Coast Guard's appropriations are comparable as its FY2017 funding was not proposed in the CAS structure. However, no authoritative crosswalk between the House Appropriations Committee proposal in the CAS structure and Senate Appropriations Committee proposal in the legacy structure is publicly available. Generally, the homeland security appropriations bill includes all annual appropriations provided for DHS, allocating resources to every departmental component. Discretionary appropriations provide roughly two-thirds to three-fourths of the annual funding for DHS operations, depending how one accounts for disaster relief spending and funding for overseas contingency operations. The remainder of the budget is a mix of fee revenues, trust fund resources, and mandatory spending. Appropriations measures for DHS typically have been organized into five titles. The first four are thematic groupings of components: Departmental Management and Operations; Security, Enforcement, and Investigations; Protection, Preparedness, Response, and Recovery; and Research and Development, Training, and Services. A fifth title contains general provisions, the impact of which may reach across the entire department, impact multiple components, or focus on a single activity. The following pie chart presents a comparison of the share of annual appropriations requested for the components funded in each of the first four titles, highlighting the components discussed in this report. As noted above, the Security, Enforcement, and Investigations title (Title II) of the DHS appropriations bill is the largest of the four main titles, providing funding for CBP, ICE, TSA, USCG, and USSS. Some provisions in Title V, General Provisions, may affect the total funding provided for some of these components. The Administration requested $32.27 billion in FY2017 net discretionary budget authority for components included in this title, as part of a total budget for these components of $40.27 billion for FY2017. The appropriations request was $797 million (2.4%) less than was provided for FY2016. In addition, in the budget request for the Department of Defense, the Administration requested a transfer of $163 million of Overseas Contingency Operations/Global War on Terror designated funding (OCO) from the Navy to the USCG. Senate Appropriations Committee-reported S. 3001 would have provided the components included in this title $32.92 billion in net discretionary budget authority, $652 million (2.0%) more than requested, but $145 million (0.4%) more than was provided in FY2016. In addition, the Senate Appropriations Committee recommended $163 million in OCO-designated funding for USCG be appropriated directly to the USCG, rather than be provided as a transfer. House Appropriations Committee-reported H.R. 5634 would provide the components included in this title $32.85 billion in net discretionary budget authority. This would have been $592 million (1.8%) more than requested, but $206 million (0.6%) less than was provided in FY2016. The House Appropriations Committee sought to provide $163 million in OCO-designated funding as a transfer from the Navy in the Department of Defense appropriations bill, as requested. These bills were not voted on in either body, and no annual appropriations bill for DHS was enacted prior to the end of FY2016. On September 29, 2016, the President signed into law P.L. 114-223 , which contained a continuing resolution that funds the government at the same rate of operations as FY2016, minus 0.496% through December 9, 2017. A second continuing resolution was signed into law on December 10, 2016 ( P.L. 114-254 ), funding the government at the same rate of operations as FY2016, minus 0.1901%, through April 28, 2017. The second continuing resolution contained a new provision, Section 163, which provided certain budgetary flexibility to CBP, ICE, TSA, and the Coast Guard. The Administration requested flexibility not only to maintain staffing levels of CBP and ICE, but also flexibility for them to maintain border security and fulfil immigration enforcement priorities. In their request, they specifically noted this flexibility was for both salaries and non-pay expenses, and was needed to "respond to unpredictable surges in migration."