Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Derivative assets:
Derivative assets	$ 1.1	$ 7.2
Money market funds
Equity securities:
Equity securities	562.6	337.5
Publicly-traded equity securities
Equity securities:
Equity securities	12.2	5.1
Fair Value, Measurements, Recurring
Available-for-sale debt securities:
Available-for-sale debt securities	837.8	629.0
Equity securities:
Equity securities	623.9	380.6
Derivative assets:
Derivative assets	1.1	7.2
Total assets measured at fair value on a recurring basis	1,462.8	1,016.8
Derivative liabilities:
Derivative liabilities	(89.0)	(80.8)
Total liabilities measured at fair value on a recurring basis	(89.0)	(80.8)
Fair Value, Measurements, Recurring | Cash equivalents
Derivative assets:
Total assets measured at fair value on a recurring basis	836.5	665.7
Fair Value, Measurements, Recurring | Short-term investments
Derivative assets:
Total assets measured at fair value on a recurring basis	160.3	139.4
Fair Value, Measurements, Recurring | Long-term investments
Derivative assets:
Total assets measured at fair value on a recurring basis	385.4	116.8
Fair Value, Measurements, Recurring | Prepaid expenses and other current assets
Derivative assets:
Total assets measured at fair value on a recurring basis	4.6	7.1
Fair Value, Measurements, Recurring | Other long-term assets
Derivative assets:
Total assets measured at fair value on a recurring basis	76.0	87.8
Fair Value, Measurements, Recurring | Other accrued liabilities
Derivative liabilities:
Total liabilities measured at fair value on a recurring basis	(12.0)	(6.2)
Fair Value, Measurements, Recurring | Other long-term liabilities
Derivative liabilities:
Total liabilities measured at fair value on a recurring basis	(77.0)	(74.6)
Fair Value, Measurements, Recurring | Foreign exchange contracts
Derivative assets:
Derivative assets	1.1	7.2
Derivative liabilities:
Derivative liabilities	(12.0)	(7.2)
Fair Value, Measurements, Recurring | Interest rate contracts
Derivative assets:
Derivative assets	0.0	0.0
Derivative liabilities:
Derivative liabilities	(77.0)	(73.6)
Fair Value, Measurements, Recurring | Asset-backed and mortgage-backed securities
Available-for-sale debt securities:
Available-for-sale debt securities	106.5	38.0
Fair Value, Measurements, Recurring | Certificates of deposit
Available-for-sale debt securities:
Available-for-sale debt securities	6.8	3.0
Fair Value, Measurements, Recurring | Commercial paper
Available-for-sale debt securities:
Available-for-sale debt securities	77.2	41.1
Fair Value, Measurements, Recurring | Corporate debt securities
Available-for-sale debt securities:
Available-for-sale debt securities	309.4	159.6
Fair Value, Measurements, Recurring | Foreign government debt securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	5.1
Fair Value, Measurements, Recurring | Time deposits
Available-for-sale debt securities:
Available-for-sale debt securities	202.2	273.6
Fair Value, Measurements, Recurring | U.S. government agency securities
Available-for-sale debt securities:
Available-for-sale debt securities	6.0	4.0
Fair Value, Measurements, Recurring | U.S. government securities
Available-for-sale debt securities:
Available-for-sale debt securities	99.3	54.9
Fair Value, Measurements, Recurring | Privately-held debt and redeemable preferred stock securities
Available-for-sale debt securities:
Available-for-sale debt securities	30.4	49.7
Fair Value, Measurements, Recurring | Money market funds
Equity securities:
Equity securities	562.6	337.5
Fair Value, Measurements, Recurring | Mutual funds
Equity securities:
Equity securities	49.1	38.0
Fair Value, Measurements, Recurring | Publicly-traded equity securities
Equity securities:
Equity securities	12.2	5.1
Quoted Prices in Active Markets For Identical Assets (Level 1) | Fair Value, Measurements, Recurring
Available-for-sale debt securities:
Available-for-sale debt securities	58.4	20.0
Equity securities:
Equity securities	623.9	380.6
Derivative assets:
Derivative assets	0.0	0.0
Total assets measured at fair value on a recurring basis	682.3	400.6
Derivative liabilities:
Derivative liabilities	0.0	0.0
Total liabilities measured at fair value on a recurring basis	0.0	0.0
Quoted Prices in Active Markets For Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Cash equivalents
Derivative assets:
Total assets measured at fair value on a recurring basis	562.6	337.5
Quoted Prices in Active Markets For Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Short-term investments
Derivative assets:
Total assets measured at fair value on a recurring basis	21.5	12.8
Quoted Prices in Active Markets For Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Long-term investments
Derivative assets:
Total assets measured at fair value on a recurring basis	49.1	12.3
Quoted Prices in Active Markets For Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Prepaid expenses and other current assets
Derivative assets:
Total assets measured at fair value on a recurring basis	3.5	2.5
Quoted Prices in Active Markets For Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Other long-term assets
Derivative assets:
Total assets measured at fair value on a recurring basis	45.6	35.5
Quoted Prices in Active Markets For Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Other accrued liabilities
Derivative liabilities:
Total liabilities measured at fair value on a recurring basis	0.0	0.0
Quoted Prices in Active Markets For Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Other long-term liabilities
Derivative liabilities:
Total liabilities measured at fair value on a recurring basis	0.0	0.0
Quoted Prices in Active Markets For Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Foreign exchange contracts
Derivative assets:
Derivative assets	0.0	0.0
Derivative liabilities:
Derivative liabilities	0.0	0.0
Quoted Prices in Active Markets For Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Interest rate contracts
Derivative assets:
Derivative assets	0.0	0.0
Derivative liabilities:
Derivative liabilities	0.0	0.0
Quoted Prices in Active Markets For Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Asset-backed and mortgage-backed securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Quoted Prices in Active Markets For Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Certificates of deposit
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Quoted Prices in Active Markets For Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Commercial paper
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Quoted Prices in Active Markets For Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Corporate debt securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Quoted Prices in Active Markets For Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Foreign government debt securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Quoted Prices in Active Markets For Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Time deposits
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Quoted Prices in Active Markets For Identical Assets (Level 1) | Fair Value, Measurements, Recurring | U.S. government agency securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Quoted Prices in Active Markets For Identical Assets (Level 1) | Fair Value, Measurements, Recurring | U.S. government securities
Available-for-sale debt securities:
Available-for-sale debt securities	58.4	20.0
Quoted Prices in Active Markets For Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Privately-held debt and redeemable preferred stock securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Quoted Prices in Active Markets For Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Money market funds
Equity securities:
Equity securities	562.6	337.5
Quoted Prices in Active Markets For Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Mutual funds
Equity securities:
Equity securities	49.1	38.0
Quoted Prices in Active Markets For Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Publicly-traded equity securities
Equity securities:
Equity securities	12.2	5.1
Significant Other Observable Remaining Inputs (Level 2) | Fair Value, Measurements, Recurring
Available-for-sale debt securities:
Available-for-sale debt securities	749.0	559.3
Equity securities:
Equity securities	0.0	0.0
Derivative assets:
Derivative assets	1.1	7.2
Total assets measured at fair value on a recurring basis	750.1	566.5
Derivative liabilities:
Derivative liabilities	(89.0)	(80.8)
Total liabilities measured at fair value on a recurring basis	(89.0)	(80.8)
Significant Other Observable Remaining Inputs (Level 2) | Fair Value, Measurements, Recurring | Cash equivalents
Derivative assets:
Total assets measured at fair value on a recurring basis	273.9	328.2
Significant Other Observable Remaining Inputs (Level 2) | Fair Value, Measurements, Recurring | Short-term investments
Derivative assets:
Total assets measured at fair value on a recurring basis	138.8	126.6
Significant Other Observable Remaining Inputs (Level 2) | Fair Value, Measurements, Recurring | Long-term investments
Derivative assets:
Total assets measured at fair value on a recurring basis	336.3	104.5
Significant Other Observable Remaining Inputs (Level 2) | Fair Value, Measurements, Recurring | Prepaid expenses and other current assets
Derivative assets:
Total assets measured at fair value on a recurring basis	1.1	4.6
Significant Other Observable Remaining Inputs (Level 2) | Fair Value, Measurements, Recurring | Other long-term assets
Derivative assets:
Total assets measured at fair value on a recurring basis	0.0	2.6
Significant Other Observable Remaining Inputs (Level 2) | Fair Value, Measurements, Recurring | Other accrued liabilities
Derivative liabilities:
Total liabilities measured at fair value on a recurring basis	(12.0)	(6.2)
Significant Other Observable Remaining Inputs (Level 2) | Fair Value, Measurements, Recurring | Other long-term liabilities
Derivative liabilities:
Total liabilities measured at fair value on a recurring basis	(77.0)	(74.6)
Significant Other Observable Remaining Inputs (Level 2) | Fair Value, Measurements, Recurring | Foreign exchange contracts
Derivative assets:
Derivative assets	1.1	7.2
Derivative liabilities:
Derivative liabilities	(12.0)	(7.2)
Significant Other Observable Remaining Inputs (Level 2) | Fair Value, Measurements, Recurring | Interest rate contracts
Derivative assets:
Derivative assets	0.0	0.0
Derivative liabilities:
Derivative liabilities	(77.0)	(73.6)
Significant Other Observable Remaining Inputs (Level 2) | Fair Value, Measurements, Recurring | Asset-backed and mortgage-backed securities
Available-for-sale debt securities:
Available-for-sale debt securities	106.5	38.0
Significant Other Observable Remaining Inputs (Level 2) | Fair Value, Measurements, Recurring | Certificates of deposit
Available-for-sale debt securities:
Available-for-sale debt securities	6.8	3.0
Significant Other Observable Remaining Inputs (Level 2) | Fair Value, Measurements, Recurring | Commercial paper
Available-for-sale debt securities:
Available-for-sale debt securities	77.2	41.1
Significant Other Observable Remaining Inputs (Level 2) | Fair Value, Measurements, Recurring | Corporate debt securities
Available-for-sale debt securities:
Available-for-sale debt securities	309.4	159.6
Significant Other Observable Remaining Inputs (Level 2) | Fair Value, Measurements, Recurring | Foreign government debt securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	5.1
Significant Other Observable Remaining Inputs (Level 2) | Fair Value, Measurements, Recurring | Time deposits
Available-for-sale debt securities:
Available-for-sale debt securities	202.2	273.6
Significant Other Observable Remaining Inputs (Level 2) | Fair Value, Measurements, Recurring | U.S. government agency securities
Available-for-sale debt securities:
Available-for-sale debt securities	6.0	4.0
Significant Other Observable Remaining Inputs (Level 2) | Fair Value, Measurements, Recurring | U.S. government securities
Available-for-sale debt securities:
Available-for-sale debt securities	40.9	34.9
Significant Other Observable Remaining Inputs (Level 2) | Fair Value, Measurements, Recurring | Privately-held debt and redeemable preferred stock securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Significant Other Observable Remaining Inputs (Level 2) | Fair Value, Measurements, Recurring | Money market funds
Equity securities:
Equity securities	0.0	0.0
Significant Other Observable Remaining Inputs (Level 2) | Fair Value, Measurements, Recurring | Mutual funds
Equity securities:
Equity securities	0.0	0.0
Significant Other Observable Remaining Inputs (Level 2) | Fair Value, Measurements, Recurring | Publicly-traded equity securities
Equity securities:
Equity securities	0.0	0.0
Significant Other Unobservable Remaining Inputs (Level 3) | Fair Value, Measurements, Recurring
Available-for-sale debt securities:
Available-for-sale debt securities	30.4	49.7
Equity securities:
Equity securities	0.0	0.0
Derivative assets:
Derivative assets	0.0	0.0
Total assets measured at fair value on a recurring basis	30.4	49.7
Derivative liabilities:
Derivative liabilities	0.0	0.0
Total liabilities measured at fair value on a recurring basis	0.0	0.0
Significant Other Unobservable Remaining Inputs (Level 3) | Fair Value, Measurements, Recurring | Cash equivalents
Derivative assets:
Total assets measured at fair value on a recurring basis	0.0	0.0
Significant Other Unobservable Remaining Inputs (Level 3) | Fair Value, Measurements, Recurring | Short-term investments
Derivative assets:
Total assets measured at fair value on a recurring basis	0.0	0.0
Significant Other Unobservable Remaining Inputs (Level 3) | Fair Value, Measurements, Recurring | Long-term investments
Derivative assets:
Total assets measured at fair value on a recurring basis	0.0	0.0
Significant Other Unobservable Remaining Inputs (Level 3) | Fair Value, Measurements, Recurring | Prepaid expenses and other current assets
Derivative assets:
Total assets measured at fair value on a recurring basis	0.0	0.0
Significant Other Unobservable Remaining Inputs (Level 3) | Fair Value, Measurements, Recurring | Other long-term assets
Derivative assets:
Total assets measured at fair value on a recurring basis	30.4	49.7
Significant Other Unobservable Remaining Inputs (Level 3) | Fair Value, Measurements, Recurring | Other accrued liabilities
Derivative liabilities:
Total liabilities measured at fair value on a recurring basis	0.0	0.0
Significant Other Unobservable Remaining Inputs (Level 3) | Fair Value, Measurements, Recurring | Other long-term liabilities
Derivative liabilities:
Total liabilities measured at fair value on a recurring basis	0.0	0.0
Significant Other Unobservable Remaining Inputs (Level 3) | Fair Value, Measurements, Recurring | Foreign exchange contracts
Derivative assets:
Derivative assets	0.0	0.0
Derivative liabilities:
Derivative liabilities	0.0	0.0
Significant Other Unobservable Remaining Inputs (Level 3) | Fair Value, Measurements, Recurring | Interest rate contracts
Derivative assets:
Derivative assets	0.0	0.0
Derivative liabilities:
Derivative liabilities	0.0	0.0
Significant Other Unobservable Remaining Inputs (Level 3) | Fair Value, Measurements, Recurring | Asset-backed and mortgage-backed securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Significant Other Unobservable Remaining Inputs (Level 3) | Fair Value, Measurements, Recurring | Certificates of deposit
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Significant Other Unobservable Remaining Inputs (Level 3) | Fair Value, Measurements, Recurring | Commercial paper
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Significant Other Unobservable Remaining Inputs (Level 3) | Fair Value, Measurements, Recurring | Corporate debt securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Significant Other Unobservable Remaining Inputs (Level 3) | Fair Value, Measurements, Recurring | Foreign government debt securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Significant Other Unobservable Remaining Inputs (Level 3) | Fair Value, Measurements, Recurring | Time deposits
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Significant Other Unobservable Remaining Inputs (Level 3) | Fair Value, Measurements, Recurring | U.S. government agency securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Significant Other Unobservable Remaining Inputs (Level 3) | Fair Value, Measurements, Recurring | U.S. government securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Significant Other Unobservable Remaining Inputs (Level 3) | Fair Value, Measurements, Recurring | Privately-held debt and redeemable preferred stock securities
Available-for-sale debt securities:
Available-for-sale debt securities	30.4	49.7
Significant Other Unobservable Remaining Inputs (Level 3) | Fair Value, Measurements, Recurring | Money market funds
Equity securities:
Equity securities	0.0	0.0
Significant Other Unobservable Remaining Inputs (Level 3) | Fair Value, Measurements, Recurring | Mutual funds
Equity securities:
Equity securities	0.0	0.0
Significant Other Unobservable Remaining Inputs (Level 3) | Fair Value, Measurements, Recurring | Publicly-traded equity securities
Equity securities:
Equity securities	$ 0.0	$ 0.0