Stock-based Compensation Expense and Share Repurchase Programs - Stock Options Outstanding and Exercisable (Details) shares in Thousands	9 Months Ended
	Sep. 30, 2019 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Exercise price range, options outstanding (in shares) | shares	8,090
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	7 years 7 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 128.89
Exercise price range, options exercisable (in shares) | shares	4,690
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 109.42
$29.07–$40.00
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Exercise price, low end of range (in dollars per share)	29.07
Exercise price, high end of range (in dollars per share)	$ 40
Exercise price range, options outstanding (in shares) | shares	186
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	1 year 5 months 19 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 36.89
Exercise price range, options exercisable (in shares) | shares	186
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 36.89
$40.01–$60.00
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Exercise price, low end of range (in dollars per share)	40.01
Exercise price, high end of range (in dollars per share)	$ 60
Exercise price range, options outstanding (in shares) | shares	379
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	2 years 8 months 23 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 50.00
Exercise price range, options exercisable (in shares) | shares	379
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 50.00
$60.01–$80.00
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Exercise price, low end of range (in dollars per share)	60.01
Exercise price, high end of range (in dollars per share)	$ 80
Exercise price range, options outstanding (in shares) | shares	299
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	4 years 7 months 13 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 73.01
Exercise price range, options exercisable (in shares) | shares	294
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 72.96
$80.01–$100.00
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Exercise price, low end of range (in dollars per share)	80.01
Exercise price, high end of range (in dollars per share)	$ 100
Exercise price range, options outstanding (in shares) | shares	2,183
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	6 years 4 months 28 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 89.27
Exercise price range, options exercisable (in shares) | shares	1,477
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 89.78
$100.01–$120.00
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Exercise price, low end of range (in dollars per share)	100.01
Exercise price, high end of range (in dollars per share)	$ 120
Exercise price range, options outstanding (in shares) | shares	597
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	5 years 4 months 13 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 109.29
Exercise price range, options exercisable (in shares) | shares	592
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 109.25
$120.01–$140.00
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Exercise price, low end of range (in dollars per share)	120.01
Exercise price, high end of range (in dollars per share)	$ 140.00
Exercise price range, options outstanding (in shares) | shares	707
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	5 years 10 months 20 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 130.24
Exercise price range, options exercisable (in shares) | shares	695
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 130.35
$140.01–$160.00
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Exercise price, low end of range (in dollars per share)	140.01
Exercise price, high end of range (in dollars per share)	$ 160.00
Exercise price range, options outstanding (in shares) | shares	1,203
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	8 years 4 months 2 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 155.51
Exercise price range, options exercisable (in shares) | shares	464
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 155.41
$160.01–$180.00
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Exercise price, low end of range (in dollars per share)	160.01
Exercise price, high end of range (in dollars per share)	$ 180.00
Exercise price range, options outstanding (in shares) | shares	803
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	8 years 7 months 9 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 167.65
Exercise price range, options exercisable (in shares) | shares	257
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 163.59
$180.01–$189.38
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Exercise price, low end of range (in dollars per share)	180.01
Exercise price, high end of range (in dollars per share)	$ 189.38
Exercise price range, options outstanding (in shares) | shares	1,733
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	9 years 1 month 13 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 185.35
Exercise price range, options exercisable (in shares) | shares	346
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 184.58