Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating loss	$ 106.6	$ 140.6
Tax credit carryforwards	202.4	406.1
Intangible assets	802.8	507.5
Stock-based compensation	94.6	89.2
Accrued expenses	48.6	47.3
Finance lease liabilities	103.4	118.7
Operating lease assets	81.1	65.0
Other	41.7	22.1
Gross deferred tax assets	1,481.2	1,396.5
Valuation allowance	(220.4)	(213.8)
Total deferred tax assets	1,260.8	1,182.7
Deferred tax liabilities:
Property and equipment	(118.2)	(117.0)
Acquired intangibles	(87.0)	(87.0)
Operating lease liabilities	(64.8)	(63.3)
Other	(56.3)	(32.6)
Total deferred tax liabilities	(326.3)	(299.9)
Net deferred tax assets	$ 934.5	$ 882.8