Share-based Payment Arrangements (Weighted Average Assumptions For Option Grants) (Details)	3 Months Ended
Mar. 31, 2012 Y	Mar. 26, 2011 Y
Share-based Payment Arrangements [Abstract]
Expected volatility	34.00%	35.00%
Expected dividend yield	0.42%	0.45%
Risk-free interest rate	0.90%	1.75%
Expected lives (in years)	4.0	4.0

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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