Stock-Based Compensation (Details 4) (USD $)	12 Months Ended
	Dec. 31, 2012
Non-employee director
Options outstanding and exercisable
Vesting period of initial grant to newly appointed director	2 years
Vesting period of annual grant upon re-election as director	12 months
Proration vesting period of annual grant upon re-election as director	12 months
Stock options
Options outstanding and exercisable
Number Outstanding (in shares)	6,120,000
Weighted-average Remaining Contractual Life in Years, Options Outstanding	3 years 9 months 18 days
Weighted-average Exercise Price, Options Outstanding (in dollars per share)	20.30
Options Exercisable (in shares)	5,413,000
Weighted-average Remaining Contractual Life in Years, Options Exercisable	3 years 2 months 12 days
Weighted-average Exercise Price, Options Exercisable (in dollars per share)	20.31
Stock options | Non-employee director
Options outstanding and exercisable
One-time grant of shares	6,000
Annual grant of shares upon re-election to the Board	6,000
Stock options | Exercise price, $3.10
Options outstanding and exercisable
Exercise price range, low end of range (in dollars per share)	3.10
Number Outstanding (in shares)	191,000
Weighted-average Remaining Contractual Life in Years, Options Outstanding	9 months 18 days
Weighted-average Exercise Price, Options Outstanding (in dollars per share)	3.10
Options Exercisable (in shares)	191,000
Weighted-average Remaining Contractual Life in Years, Options Exercisable	9 months 18 days
Weighted-average Exercise Price, Options Exercisable (in dollars per share)	3.10
Stock options | Exercise price range, $6.15 - $6.70
Options outstanding and exercisable
Exercise price range, low end of range (in dollars per share)	6.15
Exercise price range, high end of range (in dollars per share)	6.70
Number Outstanding (in shares)	25,000
Weighted-average Remaining Contractual Life in Years, Options Outstanding	5 years 10 months 24 days
Weighted-average Exercise Price, Options Outstanding (in dollars per share)	6.15
Options Exercisable (in shares)	25,000
Weighted-average Remaining Contractual Life in Years, Options Exercisable	5 years 10 months 24 days
Weighted-average Exercise Price, Options Exercisable (in dollars per share)	6.15
Stock options | Exercise price, $9.69
Options outstanding and exercisable
Exercise price range, low end of range (in dollars per share)	9.69
Number Outstanding (in shares)	1,140,000
Weighted-average Remaining Contractual Life in Years, Options Outstanding	1 year 3 months 18 days
Weighted-average Exercise Price, Options Outstanding (in dollars per share)	9.69
Options Exercisable (in shares)	1,140,000
Weighted-average Remaining Contractual Life in Years, Options Exercisable	1 year 3 months 18 days
Weighted-average Exercise Price, Options Exercisable (in dollars per share)	9.69
Stock options | Exercise price range, $9.70 - $16.00
Options outstanding and exercisable
Exercise price range, low end of range (in dollars per share)	9.70
Exercise price range, high end of range (in dollars per share)	16.00
Number Outstanding (in shares)	839,000
Weighted-average Remaining Contractual Life in Years, Options Outstanding	4 years 1 month 6 days
Weighted-average Exercise Price, Options Outstanding (in dollars per share)	14.71
Options Exercisable (in shares)	768,000
Weighted-average Remaining Contractual Life in Years, Options Exercisable	3 years 9 months 18 days
Weighted-average Exercise Price, Options Exercisable (in dollars per share)	14.87
Stock options | Exercise price range, $16.01- $19.80
Options outstanding and exercisable
Exercise price range, low end of range (in dollars per share)	16.01
Exercise price range, high end of range (in dollars per share)	19.80
Number Outstanding (in shares)	1,228,000
Weighted-average Remaining Contractual Life in Years, Options Outstanding	4 years 6 months
Weighted-average Exercise Price, Options Outstanding (in dollars per share)	18.17
Options Exercisable (in shares)	956,000
Weighted-average Remaining Contractual Life in Years, Options Exercisable	3 years 3 months 18 days
Weighted-average Exercise Price, Options Exercisable (in dollars per share)	18.13
Stock options | Exercise price range, $19.81- $24.71
Options outstanding and exercisable
Exercise price range, low end of range (in dollars per share)	19.81
Exercise price range, high end of range (in dollars per share)	24.71
Number Outstanding (in shares)	594,000
Weighted-average Remaining Contractual Life in Years, Options Outstanding	7 years 2 months 16 days
Weighted-average Exercise Price, Options Outstanding (in dollars per share)	22.16
Options Exercisable (in shares)	316,000
Weighted-average Remaining Contractual Life in Years, Options Exercisable	5 years 8 months 12 days
Weighted-average Exercise Price, Options Exercisable (in dollars per share)	22.38
Stock options | Exercise price range, $24.72 - $29.70
Options outstanding and exercisable
Exercise price range, low end of range (in dollars per share)	24.72
Exercise price range, high end of range (in dollars per share)	29.70
Number Outstanding (in shares)	1,124,000
Weighted-average Remaining Contractual Life in Years, Options Outstanding	4 years 1 month 6 days
Weighted-average Exercise Price, Options Outstanding (in dollars per share)	28.29
Options Exercisable (in shares)	1,038,000
Weighted-average Remaining Contractual Life in Years, Options Exercisable	3 years 7 months 6 days
Weighted-average Exercise Price, Options Exercisable (in dollars per share)	28.42
Stock options | Exercise price range, $29.71 - $35.46
Options outstanding and exercisable
Exercise price range, low end of range (in dollars per share)	29.71
Exercise price range, high end of range (in dollars per share)	35.46
Number Outstanding (in shares)	979,000
Weighted-average Remaining Contractual Life in Years, Options Outstanding	4 years 1 month 6 days
Weighted-average Exercise Price, Options Outstanding (in dollars per share)	33.52
Options Exercisable (in shares)	979,000
Weighted-average Remaining Contractual Life in Years, Options Exercisable	4 years 1 month 6 days
Weighted-average Exercise Price, Options Exercisable (in dollars per share)	33.52
RSUs | Non-employee director
Options outstanding and exercisable
One-time grant of shares	6,000
Annual grant of shares upon re-election to the Board	6,000