Stock Based Compensation Stock Based Compensation (Details) (USD $) Share data in Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Stock-Based Compensation [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	10.0
Stock or Unit Option Plan Expense	$ 2,000,000	$ 5,400,000	$ 5,300,000
Stock Issued During Period, Value, Restricted Stock Award, Gross	19,700,000	32,400,000	19,300,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	51,000,000
expense relating to vesting of stock options	800,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	11,500,000	3,600,000	10,400,000
Percent of salary maximum contribution employee stock purchase plan	6.00%
Maximum contribution to employee stock purchase plan	20,000
expense relating to vesting of stock awards	$ 18,700,000