A current perpendicular to plane (CPP) differential giant magnetoresistive (GMR) sensor that is insensitive to stray longitudinal and transverse magnetic fields. The sensor includes an in stack bias layer structure that is used to bias the magnetic moment of first and second free layers disposed at either side thereof. The bias structure includes an antiferromagnetic layer (AFM). An odd number of antiparallel (AP) coupled magnetic layers are formed on a first side of the AFM and an even number of AP coupled magnetic layers on the opposite side of the AFM.