Financial Instruments (Fair Value of Financial Instruments) (Details) - USD ($) $ in Millions | Sep. 30, 2020 | Dec. 31, 2019 |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Noncurrent investments | $ 2,476.2 | $ 1,962.4 |
Carrying Amount | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Cash equivalents | 2,374.2 | 1,025.4 |
Short-term investments, debt securities | 35 | 101 |
Equity investments without readily determinable fair values | 339.5 | 405 |
Noncurrent investments | 2,476.2 | 1,962.4 |
Short-term commercial paper borrowings | (579.9) | (1,494.2) |
Long-term debt, including current portion | (16,342.2) | (13,823) |
Carrying Amount | U.S. government and agency securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 11.8 | 7.2 |
Noncurrent investments, debt securities | 73.2 | 77.2 |
Carrying Amount | Corporate debt securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 5.5 | 81.4 |
Noncurrent investments, debt securities | 137.5 | 271.1 |
Carrying Amount | Asset-backed securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 3.6 | 2.6 |
Noncurrent investments, debt securities | 25.4 | 30 |
Carrying Amount | Other securities, current investments | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 14.1 | 9.8 |
Carrying Amount | Mortgage-backed securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Noncurrent investments, debt securities | 104.3 | 101.1 |
Carrying Amount | Other securities, noncurrent investments | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Equity securities | 97.8 | 60 |
Carrying Amount | Marketable equity securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Equity securities | 1,258.4 | 718.6 |
Carrying Amount | Equity method investments | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Equity method investments | 440.1 | 299.4 |
Cost | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Cash equivalents | 2,374.2 | 1,025.4 |
Cost | U.S. government and agency securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 11.7 | 7.2 |
Noncurrent investments, debt securities | 68.5 | 76.3 |
Cost | Corporate debt securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 5.5 | 81.1 |
Noncurrent investments, debt securities | 128 | 267.8 |
Cost | Asset-backed securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 3.6 | 2.6 |
Noncurrent investments, debt securities | 24.8 | 29.6 |
Cost | Other securities, current investments | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 14.1 | 9.8 |
Cost | Mortgage-backed securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Noncurrent investments, debt securities | 99.2 | 99.6 |
Cost | Other securities, noncurrent investments | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Equity securities | 31.4 | 27.4 |
Cost | Marketable equity securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Equity securities | 275.2 | 254.4 |
Estimate of Fair Value Measurement | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Cash equivalents | 2,374.2 | 1,025.4 |
Short-term commercial paper borrowings | (578.8) | (1,491.6) |
Long-term debt, including current portion | (16,148.2) | (15,150) |
Estimate of Fair Value Measurement | Quoted Prices in Active Markets for Identical Assets (Level 1) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Cash equivalents | 2,374.2 | 1,025.4 |
Short-term commercial paper borrowings | 0 | 0 |
Long-term debt, including current portion | 0 | 0 |
Estimate of Fair Value Measurement | Significant Other Observable Inputs (Level 2) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Cash equivalents | 0 | 0 |
Short-term commercial paper borrowings | (578.8) | (1,491.6) |
Long-term debt, including current portion | (16,148.2) | (15,150) |
Estimate of Fair Value Measurement | Significant Unobservable Inputs (Level 3) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Cash equivalents | 0 | 0 |
Short-term commercial paper borrowings | 0 | 0 |
Long-term debt, including current portion | 0 | 0 |
Estimate of Fair Value Measurement | U.S. government and agency securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 11.8 | 7.2 |
Noncurrent investments, debt securities | 73.2 | 77.2 |
Estimate of Fair Value Measurement | U.S. government and agency securities | Quoted Prices in Active Markets for Identical Assets (Level 1) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 11.8 | 7.2 |
Noncurrent investments, debt securities | 73.2 | 77.2 |
Estimate of Fair Value Measurement | U.S. government and agency securities | Significant Other Observable Inputs (Level 2) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 0 | 0 |
Noncurrent investments, debt securities | 0 | 0 |
Estimate of Fair Value Measurement | U.S. government and agency securities | Significant Unobservable Inputs (Level 3) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 0 | 0 |
Noncurrent investments, debt securities | 0 | 0 |
Estimate of Fair Value Measurement | Corporate debt securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 5.5 | 81.4 |
Noncurrent investments, debt securities | 137.5 | 271.1 |
Estimate of Fair Value Measurement | Corporate debt securities | Quoted Prices in Active Markets for Identical Assets (Level 1) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 0 | 0 |
Noncurrent investments, debt securities | 0 | 0 |
Estimate of Fair Value Measurement | Corporate debt securities | Significant Other Observable Inputs (Level 2) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 5.5 | 81.4 |
Noncurrent investments, debt securities | 137.5 | 271.1 |
Estimate of Fair Value Measurement | Corporate debt securities | Significant Unobservable Inputs (Level 3) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 0 | 0 |
Noncurrent investments, debt securities | 0 | 0 |
Estimate of Fair Value Measurement | Asset-backed securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 3.6 | 2.6 |
Noncurrent investments, debt securities | 25.4 | 30 |
Estimate of Fair Value Measurement | Asset-backed securities | Quoted Prices in Active Markets for Identical Assets (Level 1) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 0 | 0 |
Noncurrent investments, debt securities | 0 | 0 |
Estimate of Fair Value Measurement | Asset-backed securities | Significant Other Observable Inputs (Level 2) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 3.6 | 2.6 |
Noncurrent investments, debt securities | 25.4 | 30 |
Estimate of Fair Value Measurement | Asset-backed securities | Significant Unobservable Inputs (Level 3) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 0 | 0 |
Noncurrent investments, debt securities | 0 | 0 |
Estimate of Fair Value Measurement | Other securities, current investments | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 14.1 | 9.8 |
Estimate of Fair Value Measurement | Other securities, current investments | Quoted Prices in Active Markets for Identical Assets (Level 1) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 0 | 0 |
Estimate of Fair Value Measurement | Other securities, current investments | Significant Other Observable Inputs (Level 2) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 0 | 0 |
Estimate of Fair Value Measurement | Other securities, current investments | Significant Unobservable Inputs (Level 3) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments, debt securities | 14.1 | 9.8 |
Estimate of Fair Value Measurement | Mortgage-backed securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Noncurrent investments, debt securities | 104.3 | 101.1 |
Estimate of Fair Value Measurement | Mortgage-backed securities | Quoted Prices in Active Markets for Identical Assets (Level 1) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Noncurrent investments, debt securities | 0 | 0 |
Estimate of Fair Value Measurement | Mortgage-backed securities | Significant Other Observable Inputs (Level 2) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Noncurrent investments, debt securities | 104.3 | 101.1 |
Estimate of Fair Value Measurement | Mortgage-backed securities | Significant Unobservable Inputs (Level 3) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Noncurrent investments, debt securities | 0 | 0 |
Estimate of Fair Value Measurement | Other securities, noncurrent investments | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Equity securities | 97.8 | 60 |
Estimate of Fair Value Measurement | Other securities, noncurrent investments | Quoted Prices in Active Markets for Identical Assets (Level 1) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Equity securities | 0 | 0 |
Estimate of Fair Value Measurement | Other securities, noncurrent investments | Significant Other Observable Inputs (Level 2) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Equity securities | 0 | 0 |
Estimate of Fair Value Measurement | Other securities, noncurrent investments | Significant Unobservable Inputs (Level 3) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Equity securities | 97.8 | 60 |
Estimate of Fair Value Measurement | Marketable equity securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Equity securities | 1,258.4 | 718.6 |
Estimate of Fair Value Measurement | Marketable equity securities | Quoted Prices in Active Markets for Identical Assets (Level 1) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Equity securities | 1,258.4 | 718.6 |
Estimate of Fair Value Measurement | Marketable equity securities | Significant Other Observable Inputs (Level 2) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Equity securities | 0 | 0 |
Estimate of Fair Value Measurement | Marketable equity securities | Significant Unobservable Inputs (Level 3) | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Equity securities | $ 0 | $ 0 |