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Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified | Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011
--- | --- | --- | ---
Assets: |  |  |
Marketable debt securities | $ 1,245.9 | $ 3,171.7 |
Fair Value, Measurements, Recurring |  |  |
Assets: |  |  |
Cash equivalents | 424.7 | 439.4 |
Derivative contracts | 3.8 | 1.8 |
Plan assets for deferred compensation | 22.7 | 14.3 |
Total | 1,730.2 | 3,656.5 |
Liabilities: |  |  |
Derivative contracts | 23.5 | 14.4 |
Contingent consideration obligations | 280.9 | 293.9 | 151.0
Total | 304.4 | 308.3 |
Fair Value, Measurements, Recurring | Corporate debt securities |  |  |
Assets: |  |  |
Marketable debt securities | 439.8 | 1,001.0 |
Fair Value, Measurements, Recurring | Government securities |  |  |
Assets: |  |  |
Marketable debt securities | 674.7 | 1,657.8 |
Fair Value, Measurements, Recurring | Mortgage and other asset backed securities |  |  |
Assets: |  |  |
Marketable debt securities | 131.4 | 512.9 |
Fair Value, Measurements, Recurring | Marketable equity securities |  |  |
Assets: |  |  |
Investments | 11.2 | 9.0 |
Fair Value, Measurements, Recurring | Venture capital investments |  |  |
Assets: |  |  |
Investments | 21.9 | 20.3 | 23.5
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 | 11.2 | 9.0 |
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 | 11.2 | 9.0 |
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 | 424.7 | 439.4 |
Derivative contracts | 3.8 | 1.8 |
Plan assets for deferred compensation | 22.7 | 14.3 |
Total | 1,697.1 | 3,627.2 |
Liabilities: |  |  |
Derivative contracts | 23.5 | 14.4 |
Contingent consideration obligations | 0 | 0 |
Total | 23.5 | 14.4 |
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Corporate debt securities |  |  |
Assets: |  |  |
Marketable debt securities | 439.8 | 1,001.0 |
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Government securities |  |  |
Assets: |  |  |
Marketable debt securities | 674.7 | 1,657.8 |
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Mortgage and other asset backed securities |  |  |
Assets: |  |  |
Marketable debt securities | 131.4 | 512.9 |
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 | 21.9 | 20.3 |
Liabilities: |  |  |
Derivative contracts | 0 | 0 |
Contingent consideration obligations | 280.9 | 293.9 |
Total | 280.9 | 293.9 |
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 | $ 21.9 | $ 20.3 |

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