This may sound kind of dumb, and it is probably is, but I am trying to understand why some companies like Berkshire, Moody's, General Electric and Procter & Gamble borrow money ? they have been in business for decades if not more and they produce huge amounts of cash flows. why do they need to borrow money at X% if they can pay it down and use their own money (which is free) ?
I am asking since when trying to discount all future cash flows to equity owners I assume that the company will hold its debt level forever, which seems to be the case in real life, but why is it ?