Note 8. Debt and Financing Arrangements (Details) $ in Billions	12 Months Ended
	Sep. 30, 2017 USD ($) Rate
Line of Credit Facility [Line Items]
Line of Credit Facility, Description	3.5x adjusted EBITDA
Line of Credit [Member]
Line of Credit Facility [Line Items]
Long-term Debt | $	$ 1.5
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Long-term Debt | $	$ 1.5
Line Of Credit Commitment Fee Year 1 [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Commitment Fee Percentage	0.625%
Line Of Credit Commitment Fee Year 2 and 3 [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Commitment Fee Percentage	1.25%
Line Of Credit Commitment Fee Year 4 and After [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Commitment Fee Percentage	2.50%