To clone an object in jQuery:
var vi.nextSegment = jQuery.extend({}, vi.details);
NOTE: The above is a shallow copy: any nested objects or arrays will be copied by reference – meaning any changes you make to vi.nextSegment.obj[prop] will be reflected in vi.details.obj[prop]. If you want a completely new object which is completely separate from the original, you will need to do a deep copy (pass true as the first parameter):
var vi.nextSegment = jQuery.extend(true, {}, vi.details);
To read up more on extend, see here.