Despite having similar hydrophobic core volumes, the longer chain of C12EO10 favours the formation of regular, nearly spherical micelles, while TX-100 micelles are polydisperse having an aggregation number ranging from 41 to 184 molecules, and show polymorphism. According to our simulations, most TX-100 micelles would be nearly spherical or prolate, with a few torus-shaped oblate micelles. Among the nearly spherical micelles, we observe multi-domain structures without encapsulated water for assemblies with more than 100 molecules. These structures emerge to accommodate the voluminous polar tails while simultaneously maintaining the local packing of the hydrophobic groups. Our ensemble provides quantitative agreement with the SAS experiments, but due to limitations in system sizes and number of replicas, the results should be interpreted as the minimum degree of complexity needed to describe the TX-100 assemblies.