3. Fair Value Measurements Fair Value Level Table (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized Gain on Securities		$ 1,385.0
Debt Securities, Available-for-sale		370.9
Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted Investments, at Fair Value		5.6	$ 5.6
Equity Securities	[1]	3,950.5	2,672.9
Debt Securities, Available-for-sale	[2]	370.9	373.2
Forward Foreign Exchange Contracts, Asset, Fair Value Disclosure	[3]	0.5	0.6
Assets, Fair Value Disclosure		4,503.9	3,200.0
Forward Foreign Exchange Contracts, Liability, Fair Value Disclosure	[4]	0.8	0.7
Business Combination, Contingent Consideration, Liability	[5]	5.3	8.4
Liabilities, Fair Value Disclosure		6.1	9.1
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted Investments, at Fair Value		5.6	5.6
Equity Securities	[1]	3,950.5	2,672.9
Debt Securities, Available-for-sale	[2]	0.0	0.0
Forward Foreign Exchange Contracts, Asset, Fair Value Disclosure	[3]	0.0	0.0
Assets, Fair Value Disclosure		4,042.6	2,738.1
Forward Foreign Exchange Contracts, Liability, Fair Value Disclosure	[4]	0.0	0.0
Business Combination, Contingent Consideration, Liability	[5]	0.0	0.0
Liabilities, Fair Value Disclosure		0.0	0.0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted Investments, at Fair Value		0.0	0.0
Equity Securities	[1]	0.0	0.0
Debt Securities, Available-for-sale	[2]	370.9	373.2
Forward Foreign Exchange Contracts, Asset, Fair Value Disclosure	[3]	0.5	0.6
Assets, Fair Value Disclosure		461.3	461.9
Forward Foreign Exchange Contracts, Liability, Fair Value Disclosure	[4]	0.8	0.7
Business Combination, Contingent Consideration, Liability	[5]	0.0	0.0
Liabilities, Fair Value Disclosure		0.8	0.7
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted Investments, at Fair Value		0.0	0.0
Equity Securities	[1]	0.0	0.0
Debt Securities, Available-for-sale	[2]	0.0	0.0
Forward Foreign Exchange Contracts, Asset, Fair Value Disclosure	[3]	0.0	0.0
Assets, Fair Value Disclosure		0.0	0.0
Forward Foreign Exchange Contracts, Liability, Fair Value Disclosure	[4]	0.0	0.0
Business Combination, Contingent Consideration, Liability	[5]	5.3	8.4
Liabilities, Fair Value Disclosure		5.3	8.4
US Government Sponsored Agencies [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	3.2
US Government Sponsored Agencies [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	0.0
US Government Sponsored Agencies [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	3.2
US Government Sponsored Agencies [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	0.0
Asset-backed Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	0.1	0.3
Asset-backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	0.0	0.0
Asset-backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	0.1	0.3
Asset-backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	0.0	0.0
Commercial Paper [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	76.6	77.8
Commercial Paper [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	0.0	0.0
Commercial Paper [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	76.6	77.8
Commercial Paper [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	0.0	0.0
Time Deposits [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	33.6	32.7
Time Deposits [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	23.6	22.7
Time Deposits [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	10.0	10.0
Time Deposits [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	0.0	0.0
Money Market Funds [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	62.9	36.9
Money Market Funds [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	62.9	36.9
Money Market Funds [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	0.0	0.0
Money Market Funds [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	0.0	0.0
Cash Equivalents [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	176.4	147.7
Cash Equivalents [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	86.5	59.6
Cash Equivalents [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	89.9	88.1
Cash Equivalents [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	[6]	0.0	0.0
Foreign Government Debt [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	3.1
Foreign Government Debt [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	0.0
Foreign Government Debt [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	3.1
Foreign Government Debt [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	0.0
Municipal Obligations (Member) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	10.7	11.0
Municipal Obligations (Member) | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	0.0	0.0
Municipal Obligations (Member) | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	10.7	11.0
Municipal Obligations (Member) | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	0.0	0.0
Foreign Government Obligations [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	4.7	3.6
Foreign Government Obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	0.0	0.0
Foreign Government Obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	4.7	3.6
Foreign Government Obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	0.0	0.0
Corporate Debt Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	181.7	215.0
Corporate Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	0.0	0.0
Corporate Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	181.7	215.0
Corporate Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	0.0	0.0
US Government Sponsored Agencies [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	98.5	80.3
US Government Sponsored Agencies [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	0.0	0.0
US Government Sponsored Agencies [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	98.5	80.3
US Government Sponsored Agencies [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	0.0	0.0
Asset-backed Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	72.2	63.3
Asset-backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	0.0	0.0
Asset-backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	72.2	63.3
Asset-backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	0.0	0.0
Other Current Liabilities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability	[5]	3.7	3.2
Other Noncurrent Liabilities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability	[5]	1.6	5.2
Short-term Investments [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities	[1]	47.4	40.2
Debt Securities, Available-for-sale	[2]	370.8	373.0
Short-term Investments [Member] | Foreign Government Debt [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale		3.1
Short-term Investments [Member] | Municipal Obligations (Member) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale		10.7	11.0
Short-term Investments [Member] | Foreign Government Obligations [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale		4.7	3.6
Short-term Investments [Member] | Corporate Debt Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale		181.7	215.0
Short-term Investments [Member] | US Government Sponsored Agencies [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale		98.5	80.3
Short-term Investments [Member] | Asset-backed Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale		72.1	63.1
Other Investments [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities	[1]	3,903.1	2,632.7
Debt Securities, Available-for-sale	[2]	0.1	$ 0.2
Analytical Flow Cytometer Platform [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability		5.3
Sales milestone minimum amount [Member] | Analytical Flow Cytometer Platform [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, Low		$ 0.0

[1] Equity securities are included in the following accounts in the Condensed Consolidated Balance Sheets (in millions):   September 30, 2019   December 31, 2018 Short-term investments $ 47.4
  $ 40.2
Other investments 3,903.1
  2,632.7
        Total $ 3,950.5
  $ 2,672.9

[2] Available-for-sale investments are included in the following accounts in the Condensed Consolidated Balance Sheets (in millions):   September 30, 2019   December 31, 2018 Short-term investments $ 370.8
  $ 373.0
Other investments 0.1
  0.2
Total $ 370.9
  $ 373.2

[3] Forward foreign exchange contracts in an asset position are included in Other current assets in the Condensed Consolidated Balance Sheets.

[4] Forward foreign exchange contracts in a liability position are included in Other current liabilities in the Condensed Consolidated Balance Sheets.

[5] Contingent consideration liability is included in the following accounts in the Condensed Consolidated Balance Sheets (in millions):
  September 30, 2019   December 31, 2018 Other current liabilities $ 3.7
  $ 3.2
Other long-term liabilities 1.6
  5.2
   Total $ 5.3
  $ 8.4

[6] Cash equivalents are included in Cash and cash equivalents in the Condensed Consolidated Balance Sheets.