Stock-Based Compensation - Narrative (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) right $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares	Dec. 31, 2016 shares
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Unrecognized stock-based compensation expense	$ 143.1
Unrecognized stock-based compensation expense, weighted-average period recognition (in years)	1 year 21 days
Stock-based compensation expense	$ 101.7	$ 82.6	$ 90.3
Income tax benefit related to stock-based compensation expense	$ 25.1	$ 20.5	$ 34.3
Expiration period	10 years
Weighted-average per share fair value of option rights granted during the year (in dollars per share) | $ / shares	$ 116.41	$ 90.86	$ 77.14
Intrinsic value of exercised option rights	$ 1,184.0	$ 704.2	$ 955.8
Fair value of options vested	$ 43.2	$ 38.6	$ 31.3
Outstanding option rights (in shares) | shares	4,039,729	4,485,249	4,646,313	5,163,709
Weighted average remaining term for options outstanding	6 years 7 days	6 years 1 month 2 days	6 years 3 months 10 days
Weighted average remaining term for options exercisable	4 years 11 months 12 days	5 years 3 days	5 years 1 month 9 days
Shares reserved for future grants of option rights restricted stock (in shares) | shares	4,217,446	5,135,822	6,041,092
Employees
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Intrinsic value of exercised option rights	$ 285.8	$ 190.2	$ 255.5
Restricted Stock
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Weighted-average fair value of restricted stock granted during the year (in dollars per share) | $ / shares	$ 432.55	$ 404.08	$ 313.88
Time Shares
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Award vesting period	3 years
Performance shares
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Award vesting period	3 years
Service period required for vesting of grants	3 years
Stock Option
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Unrecognized stock-based compensation expense	$ 67.8
Unrecognized stock-based compensation expense, weighted-average period recognition (in years)	1 year 1 month 6 days
Vesting percentage	33.00%
Award vesting period	3 years
Restricted Stock
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Vesting percentage	33.00%
Award vesting period	3 years
Restricted Stock | Employees
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Unrecognized stock-based compensation expense	$ 73.6
Unrecognized stock-based compensation expense, weighted-average period recognition (in years)	11 months 4 days
Restricted Stock | Non-Employee Directors
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Unrecognized stock-based compensation expense	$ 1.7
Unrecognized stock-based compensation expense, weighted-average period recognition (in years)	11 months 15 days
Nonemployee Director Plan
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of appreciation rights, performance shares or performance units granted | right	0
Outstanding option rights (in shares) | shares	0	0	0
ASU 2016-09
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Reduction of income tax provision	$ 65.2	$ 43.4	$ 86.5
2006 Employee Plan
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of shares authorized (in shares) | shares	23,700,000
Number of appreciation rights, performance shares or performance units granted | right	0
Nonemployee Director Plan
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of shares authorized (in shares) | shares	200,000