Credit Facilities and Short-term Borrowings (Narrative) (Details) - USD ($)	3 Months Ended
	Dec. 31, 2017	Sep. 30, 2017
Foreign Lines of Credit And Overdraft Facilities [Member]
Debt And Line Of Credit Facility [Line Items]
Outstanding borrowings	$ 0
Revolving Credit Agreement [Member]
Debt And Line Of Credit Facility [Line Items]
Maximum borrowing capacity	1,000,000,000
Option to increase maximum borrowings to this amount	$ 1,200,000,000
Line of Credit Facility, Expiration Date	Apr. 01, 2020
Variable Rate Basis	LIBOR
Credit facility effective interest rate on outstanding borrowing	2.52%	2.29%
Outstanding borrowings	$ 66,300,000	$ 32,600,000
Minimum [Member] | Revolving Credit Agreement [Member]
Debt And Line Of Credit Facility [Line Items]
Basis Spread On Variable Rate	0.85%
Maximum [Member] | Revolving Credit Agreement [Member]
Debt And Line Of Credit Facility [Line Items]
Basis Spread On Variable Rate	1.65%