Smartphones are becoming increasingly complex software- intensive devices. The growing power demand of feature-rich applications cannot be satisfied by the improvement levels in battery technology, and therefore devices need to become leaner, more energy-efficient. Hardware manufacturers typically provide power saving features in their components, and several tech- niques have been addressed in the past to increase software energy efficiency. However, the binding for this set of techniques is still missing. We present a policy-based approach for system-level power management targeting mobile devices. Policies provide the needed flexibility to cope with power management across whole product families by implementing reusable strategies targeting specific parts of the system. Other parts of the framework combine the output from several policies to produce a consistent set of actions at the system level. The presented framework allows for efficient management of the inherent system-level complexity and represents part of the solution to the energy problem plaguing current mobile devices.