Stock-Based Compensation (Details 2) (Non-Qualified Stock Options, USD $) In Millions, except Share data in Thousands, unless otherwise specified					12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2011 $ 0 - $ 20 Y	Dec. 31, 2011 $ 20 - $ 40 Y	Dec. 31, 2011 $ 40 - $ 60 Y	Dec. 31, 2011 $ 60 - $ 80 Y	Dec. 31, 2011 $ 80 - $ 100 Y
Summary of stock options outstanding by range of exercise prices
Low end of range of exercise price (in dollars per share)					$ 0	$ 20	$ 40	$ 60	$ 80
High end of range of exercise price (in dollars per share)					$ 20	$ 40	$ 60	$ 80	$ 100
Outstanding - Stock Options (in shares)					2,524	4,402	2,362	717	651
Total stock options outstanding (in shares)	10,656	9,070	8,146	6,058
Outstanding - Aggregate Intrinsic Value	$ 81.9				$ 50.7	$ 31.2
Exercisable - Stock Options (in shares)					1,563	1,246	2,362	717	651
Total Exercisable, end of year (in shares)	6,539	5,316	4,114
Exercisable - Aggregate Intrinsic Value	$ 36.7				$ 31.4	$ 5.3
Weighted-Average Remaining Contractual Life (in years)					7.2	7.6	3.2	5.2	6.1