Schneiderman may have only just begun to use the power of his office, however, in an investigation that has already spanned roughly 18 months and forced Exxon to release roughly 3 million internal documents. It remains unclear whether he will ultimately force Tillerson to answer questions under oath, but he told The Associated Press he has the legal authority to depose the secretary of state, who served as Exxon's CEO until joining the Trump administration.