Stock Benefit Plans (Black-Scholes Option Pricing Valuation Model For Options) (Details) (Black-Scholes Option Pricing [Member])	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Black-Scholes Option Pricing [Member]
Risk-free interest rate, Range Minimum	2.28%	3.15%	2.16%
Risk-free interest rate, Range Maximum	2.90%	3.20%	2.68%
Expected life (in years)	6.75	6.75	6.75
Expected volatility, Range Minimum	25.40%	26.30%	33.50%
Expected volatility, Range Maximum	25.80%	27.60%	36.40%
Expected dividend yield, Range Minimum	2.75%	3.26%	4.15%
Expected dividend yield, Range Maximum	2.86%	3.52%	4.20%