Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Available-for-sale debt securities:
Available-for-sale debt securities	$ 770.2	$ 837.8
Derivative assets:
Derivative assets:	5.1	1.1
Cash equivalents
Available-for-sale debt securities:
Available-for-sale debt securities	69.0	273.9
Short-term investments
Available-for-sale debt securities:
Available-for-sale debt securities	258.0	148.1
Long-term investments
Available-for-sale debt securities:
Available-for-sale debt securities	412.3	385.4
Asset-backed and mortgage-backed securities
Available-for-sale debt securities:
Available-for-sale debt securities	152.1	106.5
Certificates of deposit
Available-for-sale debt securities:
Available-for-sale debt securities	20.4	6.8
Corporate debt securities
Available-for-sale debt securities:
Available-for-sale debt securities	342.5	309.4
Commercial paper
Available-for-sale debt securities:
Available-for-sale debt securities	97.4	77.2
Time deposits
Available-for-sale debt securities:
Available-for-sale debt securities	8.6	202.2
U.S. government agency securities
Available-for-sale debt securities:
Available-for-sale debt securities	14.9	6.0
U.S. government securities
Available-for-sale debt securities:
Available-for-sale debt securities	103.4	99.3
Privately-held debt and redeemable preferred stock securities
Available-for-sale debt securities:
Available-for-sale debt securities	30.9	30.4
Money market funds
Equity securities:
Equity securities	677.8	562.6
Publicly-traded equity securities
Equity securities:
Equity securities	10.6	12.2
Fair Value, Measurements, Recurring
Available-for-sale debt securities:
Available-for-sale debt securities	770.2	837.8
Equity securities:
Equity securities	736.9	623.9
Derivative assets:
Derivative assets:	5.1	1.1
Total assets measured at fair value on a recurring basis	1,512.2	1,462.8
Liabilities:
Derivative liabilities:	(70.4)	(89.0)
Total liabilities measured at fair value on a recurring basis	(70.4)	(89.0)
Fair Value, Measurements, Recurring | Cash equivalents
Derivative assets:
Total assets measured at fair value on a recurring basis	746.8	836.5
Fair Value, Measurements, Recurring | Short-term investments
Derivative assets:
Total assets measured at fair value on a recurring basis	268.7	160.3
Fair Value, Measurements, Recurring | Long-term investments
Derivative assets:
Total assets measured at fair value on a recurring basis	412.3	385.4
Fair Value, Measurements, Recurring | Prepaid expenses and other current assets
Derivative assets:
Total assets measured at fair value on a recurring basis	7.1	4.6
Fair Value, Measurements, Recurring | Other long-term assets
Derivative assets:
Total assets measured at fair value on a recurring basis	77.3	76.0
Fair Value, Measurements, Recurring | Other accrued liabilities
Liabilities:
Total liabilities measured at fair value on a recurring basis	(6.0)	(12.0)
Fair Value, Measurements, Recurring | Other long-term liabilities
Liabilities:
Total liabilities measured at fair value on a recurring basis	(64.4)	(77.0)
Fair Value, Measurements, Recurring | Foreign exchange contracts
Derivative assets:
Derivative assets:	5.1	1.1
Liabilities:
Derivative liabilities:	(6.3)	(12.0)
Fair Value, Measurements, Recurring | Interest rate contracts
Liabilities:
Derivative liabilities:	(64.1)	(77.0)
Fair Value, Measurements, Recurring | Asset-backed and mortgage-backed securities
Available-for-sale debt securities:
Available-for-sale debt securities	152.1	106.5
Fair Value, Measurements, Recurring | Certificates of deposit
Available-for-sale debt securities:
Available-for-sale debt securities	20.4	6.8
Fair Value, Measurements, Recurring | Corporate debt securities
Available-for-sale debt securities:
Available-for-sale debt securities	342.6	309.4
Fair Value, Measurements, Recurring | Commercial paper
Available-for-sale debt securities:
Available-for-sale debt securities	97.4	77.2
Fair Value, Measurements, Recurring | Time deposits
Available-for-sale debt securities:
Available-for-sale debt securities	8.6	202.2
Fair Value, Measurements, Recurring | U.S. government agency securities
Available-for-sale debt securities:
Available-for-sale debt securities	14.9	6.0
Fair Value, Measurements, Recurring | U.S. government securities
Available-for-sale debt securities:
Available-for-sale debt securities	103.3	99.3
Fair Value, Measurements, Recurring | Privately-held debt and redeemable preferred stock securities
Available-for-sale debt securities:
Available-for-sale debt securities	30.9	30.4
Fair Value, Measurements, Recurring | Money market funds
Equity securities:
Equity securities	677.8	562.6
Fair Value, Measurements, Recurring | Mutual funds
Equity securities:
Equity securities	48.5	49.1
Fair Value, Measurements, Recurring | Publicly-traded equity securities
Equity securities:
Equity securities	10.6	12.2
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1)
Available-for-sale debt securities:
Available-for-sale debt securities	60.5	58.4
Equity securities:
Equity securities	736.9	623.9
Derivative assets:
Derivative assets:	0.0	0.0
Total assets measured at fair value on a recurring basis	797.4	682.3
Liabilities:
Derivative liabilities:	0.0	0.0
Total liabilities measured at fair value on a recurring basis	0.0	0.0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | Cash equivalents
Derivative assets:
Total assets measured at fair value on a recurring basis	677.8	562.6
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | Short-term investments
Derivative assets:
Total assets measured at fair value on a recurring basis	36.9	21.5
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | Long-term investments
Derivative assets:
Total assets measured at fair value on a recurring basis	34.3	49.1
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | Prepaid expenses and other current assets
Derivative assets:
Total assets measured at fair value on a recurring basis	3.6	3.5
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | Other long-term assets
Derivative assets:
Total assets measured at fair value on a recurring basis	44.8	45.6
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | Other accrued liabilities
Liabilities:
Total liabilities measured at fair value on a recurring basis	0.0	0.0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | Other long-term liabilities
Liabilities:
Total liabilities measured at fair value on a recurring basis	0.0	0.0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | Foreign exchange contracts
Derivative assets:
Derivative assets:	0.0	0.0
Liabilities:
Derivative liabilities:	0.0	0.0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | Interest rate contracts
Liabilities:
Derivative liabilities:	0.0	0.0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | Asset-backed and mortgage-backed securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | Certificates of deposit
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | Corporate debt securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | Commercial paper
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | Time deposits
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | U.S. government agency securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | U.S. government securities
Available-for-sale debt securities:
Available-for-sale debt securities	60.5	58.4
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | Privately-held debt and redeemable preferred stock securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | Money market funds
Equity securities:
Equity securities	677.8	562.6
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | Mutual funds
Equity securities:
Equity securities	48.5	49.1
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | Publicly-traded equity securities
Equity securities:
Equity securities	10.6	12.2
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2)
Available-for-sale debt securities:
Available-for-sale debt securities	678.8	749.0
Equity securities:
Equity securities	0.0	0.0
Derivative assets:
Derivative assets:	5.1	1.1
Total assets measured at fair value on a recurring basis	683.9	750.1
Liabilities:
Derivative liabilities:	(70.4)	(89.0)
Total liabilities measured at fair value on a recurring basis	(70.4)	(89.0)
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | Cash equivalents
Derivative assets:
Total assets measured at fair value on a recurring basis	69.0	273.9
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | Short-term investments
Derivative assets:
Total assets measured at fair value on a recurring basis	231.8	138.8
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | Long-term investments
Derivative assets:
Total assets measured at fair value on a recurring basis	378.0	336.3
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | Prepaid expenses and other current assets
Derivative assets:
Total assets measured at fair value on a recurring basis	3.5	1.1
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | Other long-term assets
Derivative assets:
Total assets measured at fair value on a recurring basis	1.6	0.0
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | Other accrued liabilities
Liabilities:
Total liabilities measured at fair value on a recurring basis	(6.0)	(12.0)
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | Other long-term liabilities
Liabilities:
Total liabilities measured at fair value on a recurring basis	(64.4)	(77.0)
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | Foreign exchange contracts
Derivative assets:
Derivative assets:	5.1	1.1
Liabilities:
Derivative liabilities:	(6.3)	(12.0)
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | Interest rate contracts
Liabilities:
Derivative liabilities:	(64.1)	(77.0)
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | Asset-backed and mortgage-backed securities
Available-for-sale debt securities:
Available-for-sale debt securities	152.1	106.5
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | Certificates of deposit
Available-for-sale debt securities:
Available-for-sale debt securities	20.4	6.8
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | Corporate debt securities
Available-for-sale debt securities:
Available-for-sale debt securities	342.6	309.4
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | Commercial paper
Available-for-sale debt securities:
Available-for-sale debt securities	97.4	77.2
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | Time deposits
Available-for-sale debt securities:
Available-for-sale debt securities	8.6	202.2
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | U.S. government agency securities
Available-for-sale debt securities:
Available-for-sale debt securities	14.9	6.0
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | U.S. government securities
Available-for-sale debt securities:
Available-for-sale debt securities	42.8	40.9
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | Privately-held debt and redeemable preferred stock securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | Money market funds
Equity securities:
Equity securities	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | Mutual funds
Equity securities:
Equity securities	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | Publicly-traded equity securities
Equity securities:
Equity securities	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3)
Available-for-sale debt securities:
Available-for-sale debt securities	30.9	30.4
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	30.9	30.4
Liabilities:
Derivative liabilities:	0.0	0.0
Total liabilities measured at fair value on a recurring basis	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | Cash equivalents
Derivative assets:
Total assets measured at fair value on a recurring basis	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | Short-term investments
Derivative assets:
Total assets measured at fair value on a recurring basis	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | Long-term investments
Derivative assets:
Total assets measured at fair value on a recurring basis	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | Prepaid expenses and other current assets
Derivative assets:
Total assets measured at fair value on a recurring basis	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | Other long-term assets
Derivative assets:
Total assets measured at fair value on a recurring basis	30.9	30.4
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | Other accrued liabilities
Liabilities:
Total liabilities measured at fair value on a recurring basis	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | Other long-term liabilities
Liabilities:
Total liabilities measured at fair value on a recurring basis	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | Foreign exchange contracts
Derivative assets:
Derivative assets:	0.0	0.0
Liabilities:
Derivative liabilities:	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | Interest rate contracts
Liabilities:
Derivative liabilities:	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | Asset-backed and mortgage-backed securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | Certificates of deposit
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | Corporate debt securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | Commercial paper
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | Time deposits
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | U.S. government agency securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | U.S. government securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | Privately-held debt and redeemable preferred stock securities
Available-for-sale debt securities:
Available-for-sale debt securities	30.9	30.4
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | Money market funds
Equity securities:
Equity securities	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | Mutual funds
Equity securities:
Equity securities	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | Publicly-traded equity securities
Equity securities:
Equity securities	$ 0.0	$ 0.0