Here is information. They don't exactly spell out what they will refund and you do have to request it. Bolding mine.

http://www.usairways.com/en-US/trave...s/default.html

Non-refundable tickets
To make a change to a paper ticket, please go to the airport or contact your travel agent to make a change. If you have an electronic ticket, call Reservations or your travel agent to make a change.

Domestic flight changes are subject to a $150 fee and transatlantic/transpacific flight changes are subject to a $250 fee, in addition to any difference in fare.

Here are the rules:
If a reservation is canceled on/before the ticketed departure date, the value of the ticket may be applied toward future travel up to one year from the original issue date. Travel on the new ticket must be completed within one year of the original date of issue.
If any part of the ticket is unused after the ticketed departure date and the reservation has not been canceled, the ticket has no value.
Once the value of a non-refundable ticket has been applied towards the purchase of a new ticket, the original ticket is considered valueless.
Non-refundable tickets: all taxes are fully refundable (upon request), except the VAT for tickets sold within the U.S. and the following U.S. taxes (US; ZP; XF). YQ and YR are considered fuel surcharges, not taxes, and are non-refundable.

US Airways
Attention: Refund Fulfillment
4000 East Sky Harbor Blvd.
Phoenix, AZ 85034