Stock Repurchase Program And Shares Withheld From Vested Restricted Shares (Narrative) (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended
	Mar. 04, 2008 2008 Share Repurchase Program [Member]	Nov. 30, 2011 2008 Repurchase Program Expansion [Member]	Aug. 24, 2011 2008 Repurchase Program Expansion [Member]
Equity, Class of Treasury Stock [Line Items]
Share repurchase program, authorized amount	$ 50	$ 50	$ 36