Compensation for Mary Barra, who will become General Motors' chief executive on January 15, has not yet been determined, the automaker said in a US regulatory filing on Thursday. Barra, who is 51 but will turn 52 by the time she takes over as CEO, had a total compensation of about $4.9 million in 2012, including a $750,000 cash salary, according to the filing. A snapshot of other women top executives' compensation package: