Stock-Based Compensation (Fair Value Estimation Of Stock-Based Awards) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011 years	Dec. 31, 2010 years	Dec. 31, 2009 years
Stock-Based Incentive Plan [Abstract]
Volatility	33.00%	30.80%	37.80%
Risk-free interest rate	2.40%	2.50%	2.40%
Expected term of options (in years)	6.0	5.7	5.7
Forfeiture rate	5.50%	5.50%	5.50%
Weighted average grant date fair value per option	$ 8.13	$ 6.89	$ 5.43