Income Taxes - Schedule Of Deferred Tax Assets (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Share-based compensation expense	$ 95.6	$ 87.2
Expenses deducted in later years for tax purposes	42.0	29.1
Intangible assets	362.3	351.9
Research and other credits	56.1	40.1
Other	10.4	9.0
Gross deferred tax assets	566.4	517.3
Valuation allowance	(57.2)	(42.3)
Deferred tax assets	509.2	475.0
Deferred tax liabilities:
Fixed assets	(75.3)	(42.2)
Intangible assets	(8.3)	(7.5)
Other	0.0	(0.1)
Deferred tax liabilities	83.6	49.8
Net deferred tax assets	$ 425.6	$ 425.2