Acquisitions Acquisition (Mortara Instruments) (Details) - USD ($)		6 Months Ended
	Feb. 14, 2017	Mar. 31, 2018	Mar. 31, 2017	Feb. 28, 2017
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired		$ 0	$ 314,300,000
Goodwill		$ 1,754,200,000
Mortara [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	$ 330,000,000
Payments to Acquire Businesses, Net of Cash Acquired	311,200,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables	16,400,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory	21,500,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Other	2,800,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment	18,200,000
Goodwill	165,500,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets	4,800,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities	(22,800,000)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other	(1,200,000)
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	311,200,000
Trade names (7-year weighted average useful life) | Mortara [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		7 years
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	15,800,000
Customer relationships (8-year useful life) | Mortara [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		8 years
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	37,900,000
Developed technology (7-year useful life) | Mortara [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		7 years
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 52,300,000
Senior Unsecured 5.00% Notes due on February 14, 2025 [Member]
Business Acquisition [Line Items]
Aggregate value of debt				$ 300,000,000