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Share-Based Compensation (Assumption For Fair Value Of Options Granted) (Details)
12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free interest rate 2.60% 2.50% 2.49%
Expected volatility 27.40% 42.10% 41.00%
Dividend yield 3.66% 3.45% 3.64%
Forfeiture rate 3.81% 3.88% 5.80%
Incentive Stock Option Plans [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Weighted average expected life in years 7.4 4.5 4.5
Non-Qualified Option Plans [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Weighted average expected life in years 7.4 4.5 4.5