EX-24.4_172315 2 poa.txt POA DOCUMENT Limited Power of Attorney The undersigned hereby appoints each of Brian J. Woram, Paul M. Johnston, Anita L. Nesser and James R. Peacock III as his attorney-in-fact with full power to act in his name, place and stead for the limited purpose of executing on his behalf all forms required to be signed and filed by him under Section 16 of the Securities Exchange Act of 1934 and the rules and regulations promulgated thereunder. IN WITNESS WHEREOF, the undersigned hereunto sets his hand this 6th day of April 2005. Timothy R. Eller