The bible has a lot of history in it, but to say that it’s primarily an historical document is missing its entire point. It is a religious document, and historical incidents are presented only in a manner relevant to that faith – and with a definite editorial slant.
The language and form of Genesis indicates its source in myth. At first glance God creating the universe through Logos may not, at first glance, seem very similar to Marduk creating the world from Tiamat’s corpse, Chaos giving birth to Gaia, Nyx, Tartarus, Erebus, and Eros, or Damballa making or causing everything to form in sequence – but it is. The story attributes special creation to the divine, just as the movement of Damballa’s coils created hills and valleys, takes place within a very brief time when compared to how long we think it actually took, and pays no heed to self-contradiction (how could one have a day/night cycle before the creation of the Sun?).
And then God rests. Takes a day off. No problem – he’s earned it. Except he’s God: resting is something humans do when they’ve been working for a long time. The God of Genesis is far less anthropomorphic than Zeus, but it’s definitely noticeable.
Another issue with taking the creation story in Genesis as literal fact is that it is linear. God exists outside time; in fact, he created it with day and night, correct? It’s not a matter of ‘a day to me is a million years to you’; God can see each instant of those million years at once and poke things around at any point he likes. Time has no meaning for the divine. But Genesis is a simple story, unconcerned with such matters – it’s meant to teach people that they owe their existence to God, and getting into strange, mindbending philosophy isn’t going to cut it even now, let alone the time it was written.
edit: Looking up, you’re rather quick to throw around accusations of heresy. Mind calming down a touch?