Before anybody thinks this is weird, or unusual. Microsoft has quite often been more pragmatic about the platform offerings for their office suite than elsewhere. After all, Office exists and has existed on Apple products for a very long time. It's more unusual that it hasn't been on the iProducts than anything.
I may be remembering wrong, but isn't the fact that Office existed on the Mac for so long also a result of the deal that Microsoft and Apple struck back in the 90's? Microsoft would keep making Office for the Mac and in exchange Apple would drop it's patent suit against them.
No, Word and Excel started out on the Mac and came to Windows later. I think what you're referring to is, there was a deal in the '90s where Microsoft helped out Apple, which included investment and maintaining an Internet Explorer Mac port (this was a much bigger deal back then). This gave the company some breathing room. At the time Apple was circling the drain and everyone assumed that they would be out of business in a matter of years if not months. This was the same era as Microsoft's antitrust suits, so what Microsoft got out of it was a (very weak at the time) competitor that they could continue pointing to as evidence that they weren't a monopoly.