Debt - Schedule of Debt Instruments (Details) - USD ($)	Dec. 31, 2017	Sep. 30, 2017
Debt Instrument [Line Items]
Long-term debt	$ 4,286,818,000	$ 3,442,055,000
Less current portion	20,061,000	12,121,000
Total, net of current portion	4,266,757,000	3,429,934,000
Revolving credit note
Debt Instrument [Line Items]
Long-term debt	0	0
Receivables securitization facility due 2019
Debt Instrument [Line Items]
Long-term debt	500,000,000	500,000,000
Term loans due in 2020
Debt Instrument [Line Items]
Long-term debt	548,061,000	547,860,000
Multi-currency revolving credit facility due 2021
Debt Instrument [Line Items]
Long-term debt	0	0
Overdraft facility due 2021
Debt Instrument [Line Items]
Long-term debt	20,061,000	12,121,000
$400,000, 4.875% senior notes due 2019
Debt Instrument [Line Items]
Principal amount	$ 400,000,000
Interest rate	4.875%
Long-term debt	$ 0	398,399,000
$500,000, 3.50% senior notes due 2021
Debt Instrument [Line Items]
Principal amount	$ 500,000,000
Interest rate	3.50%
Long-term debt	$ 498,006,000	497,877,000
$500,000, 3.40% senior notes due 2024
Debt Instrument [Line Items]
Principal amount	$ 500,000,000
Interest rate	3.40%
Long-term debt	$ 496,888,000	496,766,000
$500,000, 3.25% senior notes due 2025
Debt Instrument [Line Items]
Principal amount	$ 500,000,000
Interest rate	3.25%
Long-term debt	$ 495,121,000	494,950,000
$750,000, 3.45% senior notes due 2027
Debt Instrument [Line Items]
Principal amount	$ 750,000,000
Interest rate	3.45%
Long-term debt	$ 742,150,000	0
$500,000, 4.25% senior notes due 2045
Debt Instrument [Line Items]
Principal amount	$ 500,000,000
Interest rate	4.25%
Long-term debt	$ 494,136,000	494,082,000
$500,000, 4.30% senior notes due 2047
Debt Instrument [Line Items]
Principal amount	$ 500,000,000
Interest rate	4.30%
Long-term debt	$ 492,395,000	$ 0

Face (par) amount of debt instrument at time of issuance.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
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Contractual interest rate for funds borrowed, under the debt agreement.

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-Name Accounting Standards Codification
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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