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Stock-Based Compensation Plans (Details)	9 Months Ended
Stock-Based Compensation Plans (Details)	Sep. 30, 2012	Oct. 02, 2011
Valuation of stock options granted
Expected dividend yield
Expected volatility	34.10%	36.80%
Risk-free interest rate	1.10%	2.10%
Expected life in years	6 years 8 months 12 days	6 years

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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