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Stock Based Compensation (Schedule Of Stock Option Pricing Assumptions) (Details) (USD $)
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Share-based Compensation [Abstract]      
Expected life 10 years 10 years 10 years
Interest rate 2.71% 3.40% 3.78%
Volatility 27.10% 32.77% 31.70%
Dividend yield 7.23% 7.00% 6.83%
Weighted-average fair value per share at grant date $ 1.37 $ 2.16 $ 1.92