I think a big part of that number is risk, dividends are tied to risk too.
The very idea of investing is that you take risks in exchange for profits. That is, if it fails, you lose your capital, if it succeeds, you become richer. A public provider doesn't work the same way, risk is covered by taxpayer money. If it fails, taxpayers foot the bill, if it succeeds, cheaper service.
From that, NEE pays 43.72% in dividends.
If we multiply these two numbers, we end up at 17.64% in dividends ALONE.
23% is not a really big number by a long shot.
Their other subsidiary is NextEra Energy Resources, which is not a regulated utility, and has 60% net margins. This business is basically an unregulated competitive wind and solar developer. They take full risk if they can't sell their power, but can build wherever they think there are customers willing to pay. 35% of their power is sold straight to industrial customers at private contracted prices, the rest into the grid.