Stock-Based Compensation Plans (Weighted Average Assumptions For The ESOP) (Details) (USD $)	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Stock-Based Compensation Plans
Dividend yield	2.68%	2.73%	2.71%	2.72%
Expected volatility	40.80%	41.04%	40.59%	40.82%
Risk-free interest rate	1.62%	1.79%	1.93%	2.17%
Expected term of options (in years)	4.05	4.19	4.05	4.20
Weighted-average grant-date fair value	$ 8.13	$ 5.01	$ 8.24	$ 5.29

The period of time an equity-based award is expected to be outstanding. An equity-based award's expected term is generally determined based on, among other factors, the instrument's contractual term and the effects of employees' expected exercise and post-vesting employment termination behavior.

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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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