The U.S. Nuclear Physics community is considering plans for an Electron Ion Collider (EIC) as a major new facility to follow up on the QCD research presently being done at RHIC, CEBAF, LHC, and elsewhere. The BNL design for such a facility, eRHIC, would add a high-energy, polarized electron beam to the existing RHIC complex, resulting in one of the world's most technologically advanced accelerators whose performance meets very challenging physics goals, and presents demanding requirements on instrumentation for the experimental program. I will briefly discuss the physics questions that drive the design of such a facility, describe the specific design and performance parameters for eRHIC, and examine the resulting requirements for the experimental detectors. I will present some of the ideas for realizing such detectors, and discuss the activities of the "EIC Generic Detector R&D" program. This program, funded by DOE and managed at BNL, aims to develop instrumentation technology to meet the requirements of an EIC program, and to help ensure that the techniques and resources for implementing these technologies are well established within the EIC user community.