Eventually, he's named Minister of Armaments and War Production, an office from which he personally directs the Nazi production of war materiel — often through the use of slave labor, for which he will be tried at the Nuremberg war crimes tribunal.
At the Nuremberg trial Albert Speer will be unique in the extent to which he is willing to take responsibility. He not only accepts responsibility for the areas over which he had direct control, but also a measure of collective responsibility for what the Nazi government did as a whole. This suggests greater honesty and moral integrity than other high Nazi officials.
On the other hand, there numerous examples of Albert Speer being dishonest in order to make himself (and sometimes even Hitler) look better than reality would demand. Thus his willingness to accept responsibility for war crimes becomes sharply limited by his willingness to be truthful about this actions.
He's found guilty of war crimes and crimes against humanity, but only given a sentence of 20 years instead of death because of his efforts at the end of the war to undermine Adolf Hitler's actions.