You can bet this won't be indexed to anything approaching an actual cost-of-living adjustment.
This sounds like it will only attack the "rich" today, but don't bet on it. Note that "other retirement accounts" is likely to mean aggregation of all retirement assets, including the actuarial value of pensions and similar.
Oh, all those people who thought they had done so well by screwing the taxpayer (like, for instance, Superintendents in Chicago area schools with massively-bloated pensions)?
"Your" funds will be stolen for the federal government's use too.