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Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified | Mar. 31, 2014 | Dec. 31, 2013 | Mar. 31, 2013 | Dec. 31, 2012
--- | --- | --- | --- | ---
Assets: |  |  |  |
Marketable debt securities | $ 1,155.8 | $ 1,245.9 |  |
Fair Value, Measurements, Recurring |  |  |  |
Assets: |  |  |  |
Cash equivalents | 236.1 | 424.7 |  |
Derivative contracts | 2.6 | 3.8 |  |
Plan assets for deferred compensation | 32.9 | 22.7 |  |
Total | 1,464.8 | 1,730.2 |  |
Liabilities: |  |  |  |
Derivative contracts | 19.1 | 23.5 |  |
Contingent consideration obligations | 275.1 | 280.9 | 293.7 | 293.9
Total | 294.2 | 304.4 |  |
Fair Value, Measurements, Recurring | Corporate debt securities |  |  |  |
Assets: |  |  |  |
Marketable debt securities | 536.9 | 439.8 |  |
Fair Value, Measurements, Recurring | Government securities |  |  |  |
Assets: |  |  |  |
Marketable debt securities | 466.7 | 674.7 |  |
Fair Value, Measurements, Recurring | Mortgage and other asset backed securities |  |  |  |
Assets: |  |  |  |
Marketable debt securities | 152.2 | 131.4 |  |
Fair Value, Measurements, Recurring | Marketable equity securities |  |  |  |
Assets: |  |  |  |
Investments | 13.8 | 11.2 |  |
Fair Value, Measurements, Recurring | Venture capital investments |  |  |  |
Assets: |  |  |  |
Investments | 23.6 | 21.9 | 18.0 | 20.3
Quoted Prices in Active Markets, Level 1 | Fair Value, Measurements, Recurring |  |  |  |
Assets: |  |  |  |
Cash equivalents | 0 | 0 |  |
Derivative contracts | 0 | 0 |  |
Plan assets for deferred compensation | 0 | 0 |  |
Total | 13.8 | 11.2 |  |
Liabilities: |  |  |  |
Derivative contracts | 0 | 0 |  |
Contingent consideration obligations | 0 | 0 |  |
Total | 0 | 0 |  |
Quoted Prices in Active Markets, Level 1 | Fair Value, Measurements, Recurring | Corporate debt securities |  |  |  |
Assets: |  |  |  |
Marketable debt securities | 0 | 0 |  |
Quoted Prices in Active Markets, Level 1 | Fair Value, Measurements, Recurring | Government securities |  |  |  |
Assets: |  |  |  |
Marketable debt securities | 0 | 0 |  |
Quoted Prices in Active Markets, Level 1 | Fair Value, Measurements, Recurring | Mortgage and other asset backed securities |  |  |  |
Assets: |  |  |  |
Marketable debt securities | 0 | 0 |  |
Quoted Prices in Active Markets, Level 1 | Fair Value, Measurements, Recurring | Marketable equity securities |  |  |  |
Assets: |  |  |  |
Investments | 13.8 | 11.2 |  |
Quoted Prices in Active Markets, Level 1 | Fair Value, Measurements, Recurring | Venture capital investments |  |  |  |
Assets: |  |  |  |
Investments | 0 | 0 |  |
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring |  |  |  |
Assets: |  |  |  |
Cash equivalents | 236.1 | 424.7 |  |
Derivative contracts | 2.6 | 3.8 |  |
Plan assets for deferred compensation | 32.9 | 22.7 |  |
Total | 1,427.4 | 1,697.1 |  |
Liabilities: |  |  |  |
Derivative contracts | 19.1 | 23.5 |  |
Contingent consideration obligations | 0 | 0 |  |
Total | 19.1 | 23.5 |  |
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Corporate debt securities |  |  |  |
Assets: |  |  |  |
Marketable debt securities | 536.9 | 439.8 |  |
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Government securities |  |  |  |
Assets: |  |  |  |
Marketable debt securities | 466.7 | 674.7 |  |
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Mortgage and other asset backed securities |  |  |  |
Assets: |  |  |  |
Marketable debt securities | 152.2 | 131.4 |  |
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Marketable equity securities |  |  |  |
Assets: |  |  |  |
Investments | 0 | 0 |  |
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Venture capital investments |  |  |  |
Assets: |  |  |  |
Investments | 0 | 0 |  |
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring |  |  |  |
Assets: |  |  |  |
Cash equivalents | 0 | 0 |  |
Derivative contracts | 0 | 0 |  |
Plan assets for deferred compensation | 0 | 0 |  |
Total | 23.6 | 21.9 |  |
Liabilities: |  |  |  |
Derivative contracts | 0 | 0 |  |
Contingent consideration obligations | 275.1 | 280.9 |  |
Total | 275.1 | 280.9 |  |
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring | Corporate debt securities |  |  |  |
Assets: |  |  |  |
Marketable debt securities | 0 | 0 |  |
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring | Government securities |  |  |  |
Assets: |  |  |  |
Marketable debt securities | 0 | 0 |  |
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring | Mortgage and other asset backed securities |  |  |  |
Assets: |  |  |  |
Marketable debt securities | 0 | 0 |  |
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring | Marketable equity securities |  |  |  |
Assets: |  |  |  |
Investments | 0 | 0 |  |
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring | Venture capital investments |  |  |  |
Assets: |  |  |  |
Investments | $ 23.6 | $ 21.9 |  |

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