Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions | Mar. 31, 2021 | Dec. 31, 2020 |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | $ 969.9 | $ 1,451.5 |
Derivative assets: | | |
Derivative assets: | 119.5 | 89 |
Asset-backed securities | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 70.5 | 76.7 |
Certificates of deposit | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 28.4 | 32.9 |
Commercial paper | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 81.4 | 89.3 |
Corporate debt securities | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 479.2 | 637.4 |
Foreign government debt securities | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 4.6 | 4.6 |
Time deposits | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 83.1 | 255.6 |
U.S. government agency securities | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 40.9 | 65.5 |
U.S. government securities | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 125.2 | 233.8 |
Privately-held debt and redeemable preferred stock securities | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 56.6 | 55.7 |
Money market funds | | |
Equity securities: | | |
Equity securities | 433.3 | 536.6 |
Publicly-traded equity securities | | |
Equity securities: | | |
Equity securities | 8.4 | 6.6 |
Fair Value, Measurements, Recurring | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 969.9 | 1,451.5 |
Equity securities: | | |
Equity securities | 471.8 | 572.5 |
Derivative assets: | | |
Derivative assets: | 119.5 | 89 |
Total assets measured at fair value on a recurring basis | 1,561.2 | 2,113 |
Liabilities measured at fair value: | | |
Derivative liabilities: | (8) | (0.5) |
Total liabilities measured at fair value on a recurring basis | (8) | (0.5) |
Fair Value, Measurements, Recurring | Foreign exchange contracts | | |
Derivative assets: | | |
Derivative assets: | 32.3 | 38 |
Liabilities measured at fair value: | | |
Derivative liabilities: | (6.7) | (0.5) |
Fair Value, Measurements, Recurring | Interest rate contracts | | |
Derivative assets: | | |
Derivative assets: | 87.2 | 51 |
Liabilities measured at fair value: | | |
Derivative liabilities: | (1.3) | 0 |
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 71.2 | 140 |
Equity securities: | | |
Equity securities | 471.8 | 572.5 |
Derivative assets: | | |
Derivative assets: | 0 | 0 |
Total assets measured at fair value on a recurring basis | 543 | 712.5 |
Liabilities measured at fair value: | | |
Derivative liabilities: | 0 | 0 |
Total liabilities measured at fair value on a recurring basis | 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 |
Liabilities measured at fair value: | | |
Derivative liabilities: | 0 | 0 |
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | Interest rate contracts | | |
Derivative assets: | | |
Derivative assets: | 0 | 0 |
Liabilities measured at fair value: | | |
Derivative liabilities: | 0 | 0 |
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 842.1 | 1,255.8 |
Equity securities: | | |
Equity securities | 0 | 0 |
Derivative assets: | | |
Derivative assets: | 119.5 | 89 |
Total assets measured at fair value on a recurring basis | 961.6 | 1,344.8 |
Liabilities measured at fair value: | | |
Derivative liabilities: | (8) | (0.5) |
Total liabilities measured at fair value on a recurring basis | (8) | (0.5) |
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | Foreign exchange contracts | | |
Derivative assets: | | |
Derivative assets: | 32.3 | 38 |
Liabilities measured at fair value: | | |
Derivative liabilities: | (6.7) | (0.5) |
Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | Interest rate contracts | | |
Derivative assets: | | |
Derivative assets: | 87.2 | 51 |
Liabilities measured at fair value: | | |
Derivative liabilities: | (1.3) | 0 |
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 56.6 | 55.7 |
Equity securities: | | |
Equity securities | 0 | 0 |
Derivative assets: | | |
Derivative assets: | 0 | 0 |
Total assets measured at fair value on a recurring basis | 56.6 | 55.7 |
Liabilities measured at fair value: | | |
Derivative liabilities: | 0 | 0 |
Total liabilities measured at fair value on a recurring basis | 0 | 0 |
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | Foreign exchange contracts | | |
Derivative assets: | | |
Derivative assets: | 0 | 0 |
Liabilities measured at fair value: | | |
Derivative liabilities: | 0 | 0 |
Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | Interest rate contracts | | |
Derivative assets: | | |
Derivative assets: | 0 | 0 |
Liabilities measured at fair value: | | |
Derivative liabilities: | 0 | 0 |
Fair Value, Measurements, Recurring | Asset-backed securities | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 70.5 | 76.7 |
Fair Value, Measurements, Recurring | Asset-backed securities | Quoted Prices in Active Markets For Identical Assets (Level 1) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 0 | 0 |
Fair Value, Measurements, Recurring | Asset-backed securities | Significant Other Observable Remaining Inputs (Level 2) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 70.5 | 76.7 |
Fair Value, Measurements, Recurring | Asset-backed securities | Significant Other Unobservable Remaining Inputs (Level 3) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 0 | 0 |
Fair Value, Measurements, Recurring | Certificates of deposit | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 28.4 | 32.9 |
Fair Value, Measurements, Recurring | Certificates of deposit | Quoted Prices in Active Markets For Identical Assets (Level 1) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 0 | 0 |
Fair Value, Measurements, Recurring | Certificates of deposit | Significant Other Observable Remaining Inputs (Level 2) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 28.4 | 32.9 |
Fair Value, Measurements, Recurring | Certificates of deposit | Significant Other Unobservable Remaining Inputs (Level 3) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 0 | 0 |
Fair Value, Measurements, Recurring | Commercial paper | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 81.4 | 89.3 |
Fair Value, Measurements, Recurring | Commercial paper | Quoted Prices in Active Markets For Identical Assets (Level 1) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 0 | 0 |
Fair Value, Measurements, Recurring | Commercial paper | Significant Other Observable Remaining Inputs (Level 2) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 81.4 | 89.3 |
Fair Value, Measurements, Recurring | Commercial paper | Significant Other Unobservable Remaining Inputs (Level 3) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 0 | 0 |
Fair Value, Measurements, Recurring | Corporate debt securities | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 479.2 | 637.4 |
Fair Value, Measurements, Recurring | Corporate debt securities | Quoted Prices in Active Markets For Identical Assets (Level 1) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 0 | 0 |
Fair Value, Measurements, Recurring | Corporate debt securities | Significant Other Observable Remaining Inputs (Level 2) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 479.2 | 637.4 |
Fair Value, Measurements, Recurring | Corporate debt securities | Significant Other Unobservable Remaining Inputs (Level 3) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 0 | 0 |
Fair Value, Measurements, Recurring | Foreign government debt securities | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 4.6 | 4.6 |
Fair Value, Measurements, Recurring | Foreign government debt securities | Quoted Prices in Active Markets For Identical Assets (Level 1) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 0 | 0 |
Fair Value, Measurements, Recurring | Foreign government debt securities | Significant Other Observable Remaining Inputs (Level 2) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 4.6 | 4.6 |
Fair Value, Measurements, Recurring | Foreign government debt securities | Significant Other Unobservable Remaining Inputs (Level 3) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 0 | 0 |
Fair Value, Measurements, Recurring | Time deposits | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 83.1 | 255.6 |
Fair Value, Measurements, Recurring | Time deposits | Quoted Prices in Active Markets For Identical Assets (Level 1) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 0 | 0 |
Fair Value, Measurements, Recurring | Time deposits | Significant Other Observable Remaining Inputs (Level 2) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 83.1 | 255.6 |
Fair Value, Measurements, Recurring | Time deposits | Significant Other Unobservable Remaining Inputs (Level 3) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 0 | 0 |
Fair Value, Measurements, Recurring | U.S. government agency securities | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 40.9 | 65.5 |
Fair Value, Measurements, Recurring | U.S. government agency securities | Quoted Prices in Active Markets For Identical Assets (Level 1) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 0 | 0 |
Fair Value, Measurements, Recurring | U.S. government agency securities | Significant Other Observable Remaining Inputs (Level 2) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 40.9 | 65.5 |
Fair Value, Measurements, Recurring | U.S. government agency securities | Significant Other Unobservable Remaining Inputs (Level 3) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 0 | 0 |
Fair Value, Measurements, Recurring | U.S. government securities | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 125.2 | 233.8 |
Fair Value, Measurements, Recurring | U.S. government securities | Quoted Prices in Active Markets For Identical Assets (Level 1) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 71.2 | 140 |
Fair Value, Measurements, Recurring | U.S. government securities | Significant Other Observable Remaining Inputs (Level 2) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 54 | 93.8 |
Fair Value, Measurements, Recurring | U.S. government securities | Significant Other Unobservable Remaining Inputs (Level 3) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 0 | 0 |
Fair Value, Measurements, Recurring | Privately-held debt and redeemable preferred stock securities | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 56.6 | 55.7 |
Fair Value, Measurements, Recurring | Privately-held debt and redeemable preferred stock securities | Quoted Prices in Active Markets For Identical Assets (Level 1) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 0 | 0 |
Fair Value, Measurements, Recurring | Privately-held debt and redeemable preferred stock securities | Significant Other Observable Remaining Inputs (Level 2) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 0 | 0 |
Fair Value, Measurements, Recurring | Privately-held debt and redeemable preferred stock securities | Significant Other Unobservable Remaining Inputs (Level 3) | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 56.6 | 55.7 |
Fair Value, Measurements, Recurring | Money market funds | | |
Equity securities: | | |
Equity securities | 433.3 | 536.6 |
Fair Value, Measurements, Recurring | Money market funds | Quoted Prices in Active Markets For Identical Assets (Level 1) | | |
Equity securities: | | |
Equity securities | 433.3 | 536.6 |
Fair Value, Measurements, Recurring | Money market funds | Significant Other Observable Remaining Inputs (Level 2) | | |
Equity securities: | | |
Equity securities | 0 | 0 |
Fair Value, Measurements, Recurring | Money market funds | Significant Other Unobservable Remaining Inputs (Level 3) | | |
Equity securities: | | |
Equity securities | 0 | 0 |
Fair Value, Measurements, Recurring | Mutual funds | | |
Equity securities: | | |
Equity securities | 30.1 | 29.3 |
Fair Value, Measurements, Recurring | Mutual funds | Quoted Prices in Active Markets For Identical Assets (Level 1) | | |
Equity securities: | | |
Equity securities | 30.1 | 29.3 |
Fair Value, Measurements, Recurring | Mutual funds | Significant Other Observable Remaining Inputs (Level 2) | | |
Equity securities: | | |
Equity securities | 0 | 0 |
Fair Value, Measurements, Recurring | Mutual funds | Significant Other Unobservable Remaining Inputs (Level 3) | | |
Equity securities: | | |
Equity securities | 0 | 0 |
Fair Value, Measurements, Recurring | Publicly-traded equity securities | | |
Equity securities: | | |
Equity securities | 8.4 | 6.6 |
Fair Value, Measurements, Recurring | Publicly-traded equity securities | Quoted Prices in Active Markets For Identical Assets (Level 1) | | |
Equity securities: | | |
Equity securities | 8.4 | 6.6 |
Fair Value, Measurements, Recurring | Publicly-traded equity securities | Significant Other Observable Remaining Inputs (Level 2) | | |
Equity securities: | | |
Equity securities | 0 | 0 |
Fair Value, Measurements, Recurring | Publicly-traded equity securities | Significant Other Unobservable Remaining Inputs (Level 3) | | |
Equity securities: | | |
Equity securities | 0 | 0 |
Cash equivalents | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 146.1 | 333.7 |
Cash equivalents | Fair Value, Measurements, Recurring | | |
Derivative assets: | | |
Total assets measured at fair value on a recurring basis | 562.7 | 853.5 |
Cash equivalents | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | | |
Derivative assets: | | |
Total assets measured at fair value on a recurring basis | 416.6 | 519.8 |
Cash equivalents | Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | | |
Derivative assets: | | |
Total assets measured at fair value on a recurring basis | 146.1 | 333.7 |
Cash equivalents | Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | | |
Derivative assets: | | |
Total assets measured at fair value on a recurring basis | 0 | 0 |
Short-term investments | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 285.8 | 405.5 |
Short-term investments | Fair Value, Measurements, Recurring | | |
Derivative assets: | | |
Total assets measured at fair value on a recurring basis | 294.1 | 412.1 |
Short-term investments | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | | |
Derivative assets: | | |
Total assets measured at fair value on a recurring basis | 61.8 | 101 |
Short-term investments | Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | | |
Derivative assets: | | |
Total assets measured at fair value on a recurring basis | 232.3 | 311.1 |
Short-term investments | Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | | |
Derivative assets: | | |
Total assets measured at fair value on a recurring basis | 0 | 0 |
Long-term investments | | |
Available-for-sale debt securities: | | |
Available-for-sale debt securities | 481.4 | 656.6 |
Long-term investments | Fair Value, Measurements, Recurring | | |
Derivative assets: | | |
Total assets measured at fair value on a recurring basis | 481.4 | 656.6 |
Long-term investments | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | | |
Derivative assets: | | |
Total assets measured at fair value on a recurring basis | 17.8 | 45.6 |
Long-term investments | Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | | |
Derivative assets: | | |
Total assets measured at fair value on a recurring basis | 463.6 | 611 |
Long-term investments | Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | | |
Derivative assets: | | |
Total assets measured at fair value on a recurring basis | 0 | 0 |
Prepaid expenses and other current assets | Fair Value, Measurements, Recurring | | |
Derivative assets: | | |
Total assets measured at fair value on a recurring basis | 34.6 | 37.9 |
Prepaid expenses and other current assets | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | | |
Derivative assets: | | |
Total assets measured at fair value on a recurring basis | 10.1 | 9.9 |
Prepaid expenses and other current assets | Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | | |
Derivative assets: | | |
Total assets measured at fair value on a recurring basis | 24.5 | 28 |
Prepaid expenses and other current assets | Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | | |
Derivative assets: | | |
Total assets measured at fair value on a recurring basis | 0 | 0 |
Other long-term assets | Fair Value, Measurements, Recurring | | |
Derivative assets: | | |
Total assets measured at fair value on a recurring basis | 188.4 | 152.9 |
Other long-term assets | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | | |
Derivative assets: | | |
Total assets measured at fair value on a recurring basis | 36.7 | 36.2 |
Other long-term assets | Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | | |
Derivative assets: | | |
Total assets measured at fair value on a recurring basis | 95.1 | 61 |
Other long-term assets | Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | | |
Derivative assets: | | |
Total assets measured at fair value on a recurring basis | 56.6 | 55.7 |
Other accrued liabilities | Fair Value, Measurements, Recurring | | |
Liabilities measured at fair value: | | |
Total liabilities measured at fair value on a recurring basis | (3.3) | (0.3) |
Other accrued liabilities | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | | |
Liabilities measured at fair value: | | |
Total liabilities measured at fair value on a recurring basis | 0 | 0 |
Other accrued liabilities | Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | | |
Liabilities measured at fair value: | | |
Total liabilities measured at fair value on a recurring basis | (3.3) | (0.3) |
Other accrued liabilities | Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | | |
Liabilities measured at fair value: | | |
Total liabilities measured at fair value on a recurring basis | 0 | 0 |
Other long-term liabilities | Fair Value, Measurements, Recurring | | |
Liabilities measured at fair value: | | |
Total liabilities measured at fair value on a recurring basis | (4.7) | (0.2) |
Other long-term liabilities | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets For Identical Assets (Level 1) | | |
Liabilities measured at fair value: | | |
Total liabilities measured at fair value on a recurring basis | 0 | 0 |
Other long-term liabilities | Fair Value, Measurements, Recurring | Significant Other Observable Remaining Inputs (Level 2) | | |
Liabilities measured at fair value: | | |
Total liabilities measured at fair value on a recurring basis | (4.7) | (0.2) |
Other long-term liabilities | Fair Value, Measurements, Recurring | Significant Other Unobservable Remaining Inputs (Level 3) | | |
Liabilities measured at fair value: | | |
Total liabilities measured at fair value on a recurring basis | $ 0 | $ 0 |