Fair Value Measurements (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Liabilities
Decrease in fair value of contingent consideration liability	$ 1.2
Recurring fair value measurements | Other income (expense), net
Liabilities
Net unrealized and realized gains (losses) on securities	(8.8)	$ 25.7
Recurring fair value measurements | Level 1
Assets
Total assets	752.6		$ 565.9
Liabilities
Contingent consideration	0.0		0.0
Total liabilities	0.0		0.0
Recurring fair value measurements | Level 1 | Money market funds
Assets
Total assets	476.9		459.6
Recurring fair value measurements | Level 1 | Time deposits
Assets
Total assets	253.8		75.6
Recurring fair value measurements | Level 1 | U.S. government and agency securities
Assets
Total assets	0.0		0.0
Recurring fair value measurements | Level 1 | Corporate debt securities
Assets
Total assets	0.0		0.0
Recurring fair value measurements | Level 1 | Equity securities
Assets
Total assets	21.9		30.7
Recurring fair value measurements | Level 1 | Contingent consideration
Assets
Total assets	0.0		0.0
Recurring fair value measurements | Level 2
Assets
Total assets	3,460.5		3,178.6
Liabilities
Contingent consideration	0.0		0.0
Total liabilities	0.0		0.0
Recurring fair value measurements | Level 2 | Money market funds
Assets
Total assets	0.0		0.0
Recurring fair value measurements | Level 2 | Time deposits
Assets
Total assets	0.0		0.0
Recurring fair value measurements | Level 2 | U.S. government and agency securities
Assets
Total assets	2,958.4		2,639.0
Recurring fair value measurements | Level 2 | Corporate debt securities
Assets
Total assets	502.1		539.6
Recurring fair value measurements | Level 2 | Equity securities
Assets
Total assets	0.0		0.0
Recurring fair value measurements | Level 2 | Contingent consideration
Assets
Total assets	0.0		0.0
Recurring fair value measurements | Level 3
Assets
Total assets	0.1		0.1
Liabilities
Contingent consideration	18.5		19.7
Total liabilities	18.5		19.7
Recurring fair value measurements | Level 3 | Money market funds
Assets
Total assets	0.0		0.0
Recurring fair value measurements | Level 3 | Time deposits
Assets
Total assets	0.0		0.0
Recurring fair value measurements | Level 3 | U.S. government and agency securities
Assets
Total assets	0.0		0.0
Recurring fair value measurements | Level 3 | Corporate debt securities
Assets
Total assets	0.0		0.0
Recurring fair value measurements | Level 3 | Equity securities
Assets
Total assets	0.0		0.0
Recurring fair value measurements | Level 3 | Contingent consideration
Assets
Total assets	0.1		0.1
Recurring fair value measurements | Balance
Assets
Total assets	4,213.2		3,744.6
Liabilities
Contingent consideration	18.5		19.7
Total liabilities	18.5		19.7
Recurring fair value measurements | Balance | Money market funds
Assets
Total assets	476.9		459.6
Recurring fair value measurements | Balance | Time deposits
Assets
Total assets	253.8		75.6
Recurring fair value measurements | Balance | U.S. government and agency securities
Assets
Total assets	2,958.4		2,639.0
Recurring fair value measurements | Balance | Corporate debt securities
Assets
Total assets	502.1		539.6
Recurring fair value measurements | Balance | Equity securities
Assets
Total assets	21.9		30.7
Recurring fair value measurements | Balance | Contingent consideration
Assets
Total assets	$ 0.1		$ 0.1