Stock-Based Compensation (Details 6) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Recognized non-cash stock-based compensation expense
Non-cash stock-based compensation expense recognized	$ 11,320	$ 23,182
Long-Term Performance Based Plans
Recognized non-cash stock-based compensation expense
Non-cash stock-based compensation expense recognized	4,011	8,978
Outstanding awards pursuant to performance-based stock incentive plans
Performance Based Stock Options (in shares)	9,790,850
Weighted-Average Exercise Price (in dollars per share)	$ 21.58
Restricted Performance Units (in shares)	2,117,580
LTIP 2005
Outstanding awards pursuant to performance-based stock incentive plans
Performance Based Stock Options (in shares)	3,209,500
Weighted-Average Exercise Price (in dollars per share)	$ 20.33
Restricted Performance Units (in shares)	314,830
LTIP 2008
Estimated Remaining Non-Cash, Stock-Based Compensation Expense
Remaining expense estimated to be recognized during 2013	1,061
Total estimated expense remaining over the term of the plan	1,061
Recognized non-cash stock-based compensation expense
Non-cash stock-based compensation expense recognized	2,010	5,839
Outstanding awards pursuant to performance-based stock incentive plans
Performance Based Stock Options (in shares)	1,706,350
Weighted-Average Exercise Price (in dollars per share)	$ 9.75
Restricted Performance Units (in shares)	10,250
LTIP 2013
Estimated Remaining Non-Cash, Stock-Based Compensation Expense
Estimated contingent expense subsequent to 2013	64,826
Total estimated expense remaining over the term of the plan	64,826
Outstanding awards pursuant to performance-based stock incentive plans
Performance Based Stock Options (in shares)	1,875,000
Weighted-Average Exercise Price (in dollars per share)	$ 36.40
Restricted Performance Units (in shares)	937,500
Other Employee Performance Awards
Estimated Remaining Non-Cash, Stock-Based Compensation Expense
Remaining expense estimated to be recognized during 2013	1,789
Estimated contingent expense subsequent to 2013	43,185
Total estimated expense remaining over the term of the plan	44,974
Recognized non-cash stock-based compensation expense
Non-cash stock-based compensation expense recognized	$ 2,001	$ 3,139
Outstanding awards pursuant to performance-based stock incentive plans
Performance Based Stock Options (in shares)	3,000,000
Weighted-Average Exercise Price (in dollars per share)	$ 20.39
Restricted Performance Units (in shares)	855,000