Stock-Based Awards And Other Equity Instruments (Weighted Average Assumptions Of Black-Scholes Option-Pricing Model) (Details) (USD $)	12 Months Ended
Dec. 31, 2011 years	Dec. 31, 2010 years	Dec. 31, 2009 years
Stock-Based Awards And Other Equity Instruments [Abstract]
Risk-free interest rate	1.87%	2.18%	1.75%
Expected volatility	49.94%	51.75%	49.96%
Expected life (in years)	4.68	4.72	4.72
Dividend yield	1.38%	1.25%
Weighted-average estimated fair value of options granted during the year	$ 16.90	$ 18.56	$ 6.62

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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