Stock-Based Compensation - Exercise Price for Stock Options Outstanding and Exercisable (Details) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Exercise prices for stock options outstanding and exercisable
Number of stock options outstanding (in shares)	4,312,000
Options Outstanding, Weighted-Average Exercise Price (in dollars per share)	$ 31.39
Stock options
Exercise prices for stock options outstanding and exercisable
Exercise prices, outstanding stock option awards, high end of range (in dollars per share)	$ 80.00
Number of stock options outstanding (in shares)	7,923,009	6,845,685	11,725,823	14,058,574
Options Outstanding, Weighted-Average Remaining Contractual Life	5 years 8 months 9 days
Options Outstanding, Weighted-Average Exercise Price (in dollars per share)	$ 36.21	$ 31.13	$ 24.51	$ 21.71
Number of stock options exercisable	1,892,809	1,965,585	3,299,023
Options Exercisable, Weighted-Average Remaining Contractual Life	4 years 3 months 7 days
Options Exercisable, Weighted-Average Exercise Price (in dollars per share)	$ 29.97	$ 26.82	$ 19.64
Stock options | Range of Exercise Prices $00.00 - $10.00
Exercise prices for stock options outstanding and exercisable
Exercise prices, outstanding stock option awards, high end of range (in dollars per share)	$ 10.00
Number of stock options outstanding (in shares)	208,553
Options Outstanding, Weighted-Average Remaining Contractual Life	1 year 6 months
Options Outstanding, Weighted-Average Exercise Price (in dollars per share)	$ 6.31
Number of stock options exercisable	208,553
Options Exercisable, Weighted-Average Remaining Contractual Life	1 year 6 months
Options Exercisable, Weighted-Average Exercise Price (in dollars per share)	$ 6.31
Stock options | Range Of Exercise Prices $10.01 - $20.00
Exercise prices for stock options outstanding and exercisable
Exercise prices, outstanding stock option awards, low end of range (in dollars per share)	10.01
Exercise prices, outstanding stock option awards, high end of range (in dollars per share)	$ 20.00
Number of stock options outstanding (in shares)	1,885,085
Options Outstanding, Weighted-Average Remaining Contractual Life	3 years 5 months 19 days
Options Outstanding, Weighted-Average Exercise Price (in dollars per share)	$ 15.44
Number of stock options exercisable	85,085
Options Exercisable, Weighted-Average Remaining Contractual Life	2 years 11 months 9 days
Options Exercisable, Weighted-Average Exercise Price (in dollars per share)	$ 16.73
Stock options | Range of Exercise Prices $20.01 - $30.00
Exercise prices for stock options outstanding and exercisable
Exercise prices, outstanding stock option awards, low end of range (in dollars per share)	20.01
Exercise prices, outstanding stock option awards, high end of range (in dollars per share)	$ 30.00
Number of stock options outstanding (in shares)	1,617,876
Options Outstanding, Weighted-Average Remaining Contractual Life	4 years 4 months 28 days
Options Outstanding, Weighted-Average Exercise Price (in dollars per share)	$ 26.64
Number of stock options exercisable	1,067,876
Options Exercisable, Weighted-Average Remaining Contractual Life	4 years 2 months 19 days
Options Exercisable, Weighted-Average Exercise Price (in dollars per share)	$ 25.98
Stock options | Range of Exercise Prices $30.01 - $40.00
Exercise prices for stock options outstanding and exercisable
Exercise prices, outstanding stock option awards, low end of range (in dollars per share)	30.01
Exercise prices, outstanding stock option awards, high end of range (in dollars per share)	$ 40.00
Number of stock options outstanding (in shares)	1,434,345
Options Outstanding, Weighted-Average Remaining Contractual Life	5 years 10 months 6 days
Options Outstanding, Weighted-Average Exercise Price (in dollars per share)	$ 36.09
Number of stock options exercisable	265,945
Options Exercisable, Weighted-Average Remaining Contractual Life	5 years 2 months 27 days
Options Exercisable, Weighted-Average Exercise Price (in dollars per share)	$ 34.85
Stock options | Range of Exercise Prices $40.01 - $50.00
Exercise prices for stock options outstanding and exercisable
Exercise prices, outstanding stock option awards, low end of range (in dollars per share)	40.01
Exercise prices, outstanding stock option awards, high end of range (in dollars per share)	$ 50.00
Number of stock options outstanding (in shares)	428,900
Options Outstanding, Weighted-Average Remaining Contractual Life	9 years 29 days
Options Outstanding, Weighted-Average Exercise Price (in dollars per share)	$ 46.22
Number of stock options exercisable	7,800
Options Exercisable, Weighted-Average Remaining Contractual Life	2 years 11 days
Options Exercisable, Weighted-Average Exercise Price (in dollars per share)	$ 42.84
Stock options | Range of Exercise Prices $50.01 - $60.00
Exercise prices for stock options outstanding and exercisable
Exercise prices, outstanding stock option awards, low end of range (in dollars per share)	50.01
Exercise prices, outstanding stock option awards, high end of range (in dollars per share)	$ 60.00
Number of stock options outstanding (in shares)	1,532,000
Options Outstanding, Weighted-Average Remaining Contractual Life	8 years 6 months 11 days
Options Outstanding, Weighted-Average Exercise Price (in dollars per share)	$ 56.98
Number of stock options exercisable	48,500
Options Exercisable, Weighted-Average Remaining Contractual Life	4 years
Options Exercisable, Weighted-Average Exercise Price (in dollars per share)	$ 57.58
Stock options | Range of Exercise Prices $60.01 - $70.00
Exercise prices for stock options outstanding and exercisable
Exercise prices, outstanding stock option awards, low end of range (in dollars per share)	60.01
Exercise prices, outstanding stock option awards, high end of range (in dollars per share)	$ 70.00
Number of stock options outstanding (in shares)	796,250
Options Outstanding, Weighted-Average Remaining Contractual Life	7 years 1 month 10 days
Options Outstanding, Weighted-Average Exercise Price (in dollars per share)	$ 66.56
Number of stock options exercisable	189,050
Options Exercisable, Weighted-Average Remaining Contractual Life	7 years 1 month 28 days
Options Exercisable, Weighted-Average Exercise Price (in dollars per share)	$ 65.51
Stock options | Range Of Exercise Prices From Dollars $70.01 - $80.00
Exercise prices for stock options outstanding and exercisable
Exercise prices, outstanding stock option awards, low end of range (in dollars per share)	70.01
Exercise prices, outstanding stock option awards, high end of range (in dollars per share)	$ 80.00
Number of stock options outstanding (in shares)	20,000
Options Outstanding, Weighted-Average Remaining Contractual Life	3 years
Options Outstanding, Weighted-Average Exercise Price (in dollars per share)	$ 72.89
Number of stock options exercisable	20,000
Options Exercisable, Weighted-Average Remaining Contractual Life	3 years
Options Exercisable, Weighted-Average Exercise Price (in dollars per share)	$ 72.89