It is losing energy and it is slowing down. A day now is longer than it used to be.
The slowing down is due to several factors, one notably being the sloshing of the seas. As the world turns, the oceans slosh around. It causes big ocean currents like the Gulf current and so on.
Some events slow the Earth even more, like big Earthquakes.
So one day a day will be much longer, and once ago, a day was much shorter.
It’s going on for “a long time” because there’s nothing in space to stop it from spinning. The only friction is the air and oceans that sit upon the surface.
You’ll notice in America, the storm systems come in from the Pacific and move across the continent toward the eastern seaboard. That’s also caused by Earth’s rotation, and that causes friction.
So the ocean and the air cause some friction. But they are small compared to the giant Earth. So the influence is pretty small, and it takes a long long time to slow it down. Take a look at this image which shows how much air and water are on Earth…