Fair Value Measurements - Summary of Assets and Liabilities Recorded at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Assets:
Marketable debt securities	$ 2,433.1	$ 2,051.0
Fair value, measurements, recurring
Assets:
Cash equivalents	1,632.2	626.9
Marketable equity securities	1,048.5	1,974.3
Derivative contracts	80.9	20.5
Plan assets for deferred compensation	33.4	28.2
Total	5,228.1	4,700.9
Liabilities:
Derivative contracts	10.8	217.2
Contingent consideration obligations	209.1	259.8	$ 346.1
Total	219.9	477.0
Fair value, measurements, recurring | Corporate debt securities
Assets:
Marketable debt securities	1,108.2	1,301.5
Fair value, measurements, recurring | Government securities
Assets:
Marketable debt securities	1,192.7	627.1
Fair value, measurements, recurring | Mortgage and other asset backed securities
Assets:
Marketable debt securities	132.2	122.4
Quoted Prices in Active Markets (Level 1) | Fair value, measurements, recurring
Assets:
Cash equivalents	0.0	0.0
Marketable equity securities	181.7	271.1
Derivative contracts	0.0	0.0
Plan assets for deferred compensation	0.0	0.0
Total	181.7	271.1
Liabilities:
Derivative contracts	0.0	0.0
Contingent consideration obligations	0.0	0.0
Total	0.0	0.0
Quoted Prices in Active Markets (Level 1) | Fair value, measurements, recurring | Corporate debt securities
Assets:
Marketable debt securities	0.0	0.0
Quoted Prices in Active Markets (Level 1) | Fair value, measurements, recurring | Government securities
Assets:
Marketable debt securities	0.0	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	0.0
Significant Other Observable Inputs (Level 2) | Fair value, measurements, recurring
Assets:
Cash equivalents	1,632.2	626.9
Marketable equity securities	866.8	1,703.2
Derivative contracts	80.9	20.5
Plan assets for deferred compensation	33.4	28.2
Total	5,046.4	4,429.8
Liabilities:
Derivative contracts	10.8	217.2
Contingent consideration obligations	0.0	0.0
Total	10.8	217.2
Significant Other Observable Inputs (Level 2) | Fair value, measurements, recurring | Corporate debt securities
Assets:
Marketable debt securities	1,108.2	1,301.5
Significant Other Observable Inputs (Level 2) | Fair value, measurements, recurring | Government securities
Assets:
Marketable debt securities	1,192.7	627.1
Significant Other Observable Inputs (Level 2) | Fair value, measurements, recurring | Mortgage and other asset backed securities
Assets:
Marketable debt securities	132.2	122.4
Significant Unobservable Inputs (Level 3) | Fair value, measurements, recurring
Assets:
Cash equivalents	0.0	0.0
Marketable equity securities	0.0	0.0
Derivative contracts	0.0	0.0
Plan assets for deferred compensation	0.0	0.0
Total	0.0	0.0
Liabilities:
Derivative contracts	0.0	0.0
Contingent consideration obligations	209.1	259.8
Total	209.1	259.8
Significant Unobservable Inputs (Level 3) | Fair value, measurements, recurring | Corporate debt securities
Assets:
Marketable debt securities	0.0	0.0
Significant Unobservable Inputs (Level 3) | Fair value, measurements, recurring | Government securities
Assets:
Marketable debt securities	0.0	0.0
Significant Unobservable Inputs (Level 3) | Fair value, measurements, recurring | Mortgage and other asset backed securities
Assets:
Marketable debt securities	$ 0.0	$ 0.0