Stock-Based Compensation 1 (Details)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Abstract]
Expected volatility minimum	32.83%	32.79%	32.22%
Expected volatility maximum	35.60%	34.98%	33.69%
Expected dividend yield minimum	2.45%	2.45%	2.37%
Expected dividend yield maximum	2.45%	2.47%	2.45%
Risk-free interest rate minimum	1.58%	1.78%	2.34%
Risk-free interest rate maximum	2.41%	2.40%	2.72%
Expected life minimum	4.75	4.75	4.75
Expected life maximum	6.00	6.00	6.00