Share-Based Compensation Share Based Compensation (Performance Shares Rollforward) (Details) (Performance Shares [Member], USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding and unvested, beginning balance, in shares	3,768,706	3,671,374	830,790
Weighted average grant date fair value, beginning of Period, in dollars per share	$ 20.36	$ 17.70	$ 40.56
Share based compensation (SARs or Performance shares), granted, in shares	614,006	937,788	3,764,964
Weighted average grant date fair value, granted, in dollars per share	$ 46.66	$ 32.39	$ 16.85
Performance shares, vested in period, in shares	(633,504)	(140,904)	(286,790)
Performance shares, vested, weighted average grant date fair value	$ 16.95	$ 39.00	$ 43.52
Share based compensation (SARs or Performance shares), cancelled, in shares	(1,116,212)	(699,552)	(637,590)
Weighted average grant date fair value, cancelled, in dollars per share	$ 19.31	$ 18.74	$ 30.85
Outstanding and unvested, ending balance, in shares	2,632,996	3,768,706	3,671,374
Weighted average grant date fair value, end of Period, in dollars per share	$ 27.76	$ 20.36	$ 17.70