$3m total balance cap for those who have not yet reached it.
But people with total super balances above $4m would only require to reduce it to $4m (this is what I’d do as benevolent dictator, but I’m not going to die in a ditch over it).
PS Of course governments can, and do, change rules that can either work for you or against you.
But when it comes to retirement, there needs to be very careful consideration of any new rules that work against you, as you’ve based your retirement planning on an existing set of rules. This extends to changing rules around things like the refund of excess imputation credits, as Bill Shorten found out to his detriment.