Yesterday I mentioned the Doublespeak definition of insurance as used in the health care field, when a public policy person can say with a straight face that a particular health care policy is "bad" because it only covers catastrophes. Finem Respice had a good article several years ago on the history of insurance and current efforts to affect redistribution through mispricing risk. The article is written about housing but could easily have been about health care as well.
No one has put a number on this, but my gut feel is that the largest new source of funding for health care in the plan is not new taxes (though they are large) nor price controls on doctors (though these are onerous) nor deficit spending (though this is likely to be substantial) but an implicit premium subsidy from young to old. Since insurers are extremely limited in how much they can raise the price to risky groups, healthier and younger people will have to pay absurdly high premiums for what they get to subsidize the policies of the old and sick. In a normal market young people would just refuse to buy such policies -- thus the individual mandate. They must be forced to buy them, because their purchase of these overpriced, and to them, likely useless policies will fund most of the system.