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Stock-Based Compensation (Schedule of Assumptions Used to Estimate Weighted-Average Fair Value of Options Granted) (Details)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Dividend yield	3.70%	4.50%	5.00%
Volatility	15.40%	12.86%	12.54%
Risk-free interest rate	0.87%	1.08%	2.26%
Expected life—years	5 years 1 month 6 days	5 years 9 months 18 days	6 years 3 months 18 days

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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