Stock Options (Summary of Stock Option Activity) (Details) (Employee Stock Option [Member], USD $) In Millions, except Share data in Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2011
Employee Stock Option [Member]
Outstanding at December 31, 2010, Shares	3,125
Granted, Shares	611
Exercised, Shares	(154)
Forfeited and expired, Shares	(722)
Outstanding at June 30, 2011, Shares	2,860
Expected to vest at June 30, 2011, Shares	1,181
Exercisable at June 30, 2011, Shares	1,636
Outstanding at December 31, 2010, Weighted-Average Exercise Price	$ 85.78
Granted, Weighted-Average Exercise Price	$ 38.60
Exercised, Weighted-Average Exercise Price	$ 9.00
Forfeited and expired, Weighted-Average Exercise Price	$ 168.05
Outstanding at June 30, 2011, Weighted-Average Exercise Price	$ 59.12
Expected to vest at June 30, 2011, Weighted-Average Exercise Price	$ 31.03
Exercisable at June 30, 2011, Weighted-Average Exercise Price	$ 80.09
Outstanding at June 30, 2011, Weighted-Average Remaining Contractual Term (years)	2.73
Expected to vest at June 30, 2011, Weighted-Average Remaining Contractual Term (years)	3.90
Exercisable at June 30, 2011, Weighted-Average Remaining Contractual Term (years)	1.85
Outstanding at June 30, 2011, Aggregate Intrinsic Value	$ 13.0
Expected to vest at June 30, 2011, Aggregate Intrinsic Value	4.3
Exercisable at June 30, 2011, Aggregate Intrinsic Value	$ 8.6