  The historic LHC discovery of the 125 GeV particle with properties that
closely resemble the Standard Model (SM) Higgs boson verifies our understanding
of electroweak symmetry breaking, but solidifies the need for a resolution to
the hierarchy problem. Many extensions of the SM that address the hierarchy
problem contain a non-minimal Higgs sector. Therefore, as a benchmark
alternative to the SM Higgs mechanism, we study a general 2 Higgs doublet model
(2HDM-G) framework for evaluating future sensitivity to Higgs couplings. We
study how well it can be distinguished from the SM Higgs boson by future
measurements at LHC14, ILC (250, 500,1000 GeV) and a Muon Collider (125 GeV).
Additionally, our study bears on singlet Higgs extensions of two Higgs doublet
models through predicted coupling relationships.
