Stock-Based Compensation (Details 6) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Recognized non-cash stock-based compensation expense
Non-cash stock-based compensation expense recognized	$ 4,042	$ 7,017	$ 15,362	$ 30,199
Outstanding awards pursuant to performance-based stock incentive plans
Restricted Performance Units (in shares)	1,986,830		1,986,830
Long-Term Performance Based Plans
Recognized non-cash stock-based compensation expense
Non-cash stock-based compensation expense recognized	1,923	3,773	5,934	12,751
Outstanding awards pursuant to performance-based stock incentive plans
Performance Based Stock Options (in shares)	7,840,500		7,840,500
Weighted-Average Exercise Price (in dollars per share)	$ 24.06		$ 24.06
Restricted Performance Units (in shares)	1,986,830		1,986,830
LTIP 2005
Outstanding awards pursuant to performance-based stock incentive plans
Performance Based Stock Options (in shares)	3,200,500		3,200,500
Weighted-Average Exercise Price (in dollars per share)	$ 20.33		$ 20.33
Restricted Performance Units (in shares)	301,830		301,830
LTIP 2008
Recognized non-cash stock-based compensation expense
Non-cash stock-based compensation expense recognized	1,061	2,340	3,071	8,179
LTIP 2013
Estimated Remaining Non-Cash, Stock-Based Compensation Expense
Estimated contingent expense subsequent to 2013	67,024		67,024
Total estimated expense remaining over the term of the plan	67,024		67,024
Outstanding awards pursuant to performance-based stock incentive plans
Performance Based Stock Options (in shares)	1,940,000		1,940,000
Weighted-Average Exercise Price (in dollars per share)	$ 36.48		$ 36.48
Restricted Performance Units (in shares)	970,000		970,000
Other Employee Performance Awards
Estimated Remaining Non-Cash, Stock-Based Compensation Expense
Remaining expense estimated to be recognized during 2013	271		271
Estimated contingent expense subsequent to 2013	43,074		43,074
Total estimated expense remaining over the term of the plan	43,345		43,345
Recognized non-cash stock-based compensation expense
Non-cash stock-based compensation expense recognized	$ 862	$ 1,433	$ 2,863	$ 4,572
Outstanding awards pursuant to performance-based stock incentive plans
Performance Based Stock Options (in shares)	2,700,000		2,700,000
Weighted-Average Exercise Price (in dollars per share)	$ 19.55		$ 19.55
Restricted Performance Units (in shares)	715,000		715,000