Equity-Based Compensation (Restricted Stock Awards Activity) (Details) (Restricted Stock [Member], USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding at beginning, shares	4,165	5,801
Vested, shares	(1,497)	(1,509)
Forfeited, shares	(66)	(127)
Outstanding at end, shares	2,602	4,165	5,801
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Outstanding at beginning, weighted-average grant date fair value	$ 43.25	$ 43.21
Granted, weighted-average grant date fair value			$ 44.49
Vested, weighted-average grant date fair value	$ 42.87	$ 42.96
Forfeited, weighted-average grant date fair value	$ 44.64	$ 44.59
Outstanding at end, weighted-average grant date fair value	$ 43.44	$ 43.25	$ 43.21