Equity-Based Compensation (Deferred Stock Awards Activity) (Details) (Deferred Stock Awards [Member], USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Deferred Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding at beginning, shares	6,191	6,573
Outstanding at beginning, weighted-average grant date fair value	$ 46.71	$ 51.88
Granted, shares	5,468	2,287
Granted, weighted-average grant date fair value	$ 41.92	$ 42.45	$ 25.51
Vested, shares	(2,361)	(2,356)
Vested, weighted-average grant date fair value	$ 52.86	$ 57.76
Forfeited, shares	(345)	(313)
Forfeited, weighted-average grant date fair value	$ 41.99	$ 43.13
Outstanding at end, shares	8,953	6,191	6,573
Outstanding at end, weighted-average grant date fair value	$ 42.34	$ 46.71	$ 51.88