This may not be what it seems...
News reports from down there seem to think that Johnson was promised the CEO job after the merger of Duke and progress (In order to ensure the merger happen) and then summarily screwed out of it. The board "asking" for your resignation usually means you're fired, and this happened in such record time it was obviously set up.
A contract is a contract and he gets the money unless he was in on the scheme. The NC utilities commission and AG are on the case, credit rating agencies and Wall Street are upset about the possible departure of all the Progress bigwigs he brought over, and we shall what happens.