This deliverable is a typical business case to evaluate whether an initiative has sufficient benefits to warrant an organizational investment. The detailed business case can enumerate quantitative and qualitative benefits, and tangible and intangible benefits, and can stratify value into OPEX and CAPEX.
Benefits are the reason that projects are undertaken, and all project efforts will be linked to benefits, so it is important that the benefits are clearly and accurately defined in as much detail as prudent. Further, the business case 'sells' the project to the organization so it is wise to elaborate benefits (and costs) with as much detail as possible.
Create several benefits and see them in aggregate. Allocate the benefits further to business units if you wish.