No, it just means your governors take alot of what the city earns for his own personal wallet instead of giving to you, the emperor. One million denarii in the treasury, eh? Well then, give tribute of 10k a turn to every surviving faction for 50 turns, and then bribe every army they have in the field, give a few provinces here and there to those factions, and I guarantee you'll run down your surplus in no time.

One million... I used to have that as the Brutii. If you've got one million, you can afford the corruption. No way you can run that down, even with cities all churning out units.