So if ALL power generation of the US would stop right now, EVERYTHING would still have power for 25 minutes. (ignoring all safeties tripping, and perfect load balancing)
That sounds so impressive.
It's not public.
Only if that battery was connected to 500GW of inverter capacity (and the grid was a spherical chicken -- enough intertia-replacement devices to keep timing working, enough capacity to link supply with demand etc)
No. Because neither storage nor generation is evenly spread. In some places you would have nothing, in some you could have potentially hours.
In practical terms, you would most probably get nothing, because situation like this would lead to complete grid breakdown and interruption of service.