Stock-Based Compensation (Details)	6 Months Ended
	Jun. 30, 2012 Y
Stock-Based Compensation Activity
Vesting period, low end of range (in years)	1
Vesting period, high end of range (in years)	3
Expiration of annual grants (in years)	10
Retirement age eligibility for employees (in years)	55
Retirement eligibility for employees, minimum years of service required (in years)	5
Percent of stock-based compensation related to retiree-eligible population (as a percent)	30.00%
Number of shares available for grant under the 2008 Long Term Incentive Plan Program	12,315,394