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Share-Based Compensation Plans (Details 1)	12 Months Ended
Share-Based Compensation Plans (Details 1)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Black-Scholes option-pricing model
Expected Term (years)	3 years	3 years	3 years
Risk-Free Interest Rate	0.39%	0.71%	1.23%
Expected Dividend Yield	8.21%	7.31%	7.66%
Expected Volatility	21.12%	33.58%	40.29%
Forfeiture Rate	1.00%	2.00%	10.00%

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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