Debt - Schedule of Long-term Debt Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Debt Instrument [Line Items]
Long Term Debt	$ 7,360,000
Finance lease obligation	18,739	$ 8,631
Total long-term debt	7,378,739	4,568,631
Less:
Net original issue (premium) / discount on unsecured senior notes and debentures	2,811	583
Debt issuance cost	45,271	36,104
Current maturities	2,400,452	165
Long-term debt	4,930,205	4,531,779
Unsecured 0.625% Senior Notes, due 2023
Debt Instrument [Line Items]
Long Term Debt	$ 1,100,000	0
Less:
Interest rate	0.625%
Unsecured 3.00% Senior Notes, due 2027
Debt Instrument [Line Items]
Long Term Debt	$ 500,000	500,000
Less:
Interest rate	3.00%
Unsecured 2.625% Senior Notes, due 2029
Debt Instrument [Line Items]
Long Term Debt	$ 300,000	300,000
Less:
Interest rate	2.625%
Unsecured 1.50% Senior Notes, due 2031
Debt Instrument [Line Items]
Long Term Debt	$ 600,000	0
Less:
Interest rate	1.50%
Unsecured 5.95% Senior Notes, due 2034
Debt Instrument [Line Items]
Long Term Debt	$ 200,000	200,000
Less:
Interest rate	5.95%
Unsecured 5.50% Senior Notes, due 2041
Debt Instrument [Line Items]
Long Term Debt	$ 400,000	400,000
Less:
Interest rate	5.50%
Unsecured 4.15% Senior Notes, due 2043
Debt Instrument [Line Items]
Long Term Debt	$ 500,000	500,000
Less:
Interest rate	4.15%
Unsecured 4.125% Senior Notes, due 2044
Debt Instrument [Line Items]
Long Term Debt	$ 750,000	750,000
Less:
Interest rate	4.125%
Unsecured 4.30% Senior Notes, due 2048
Debt Instrument [Line Items]
Long Term Debt	$ 600,000	600,000
Less:
Interest rate	4.30%
Unsecured 4.125% Senior Notes, due 2049
Debt Instrument [Line Items]
Long Term Debt	$ 450,000	450,000
Less:
Interest rate	4.125%
Unsecured 3.375% Senior Notes, due 2049
Debt Instrument [Line Items]
Long Term Debt	$ 500,000	500,000
Less:
Interest rate	3.375%
Floating-rate term loan, due April 2022
Debt Instrument [Line Items]
Long Term Debt	$ 200,000	200,000
Floating-rate Senior Notes, due 2023
Debt Instrument [Line Items]
Long Term Debt	1,100,000	0
Medium term Series A notes, 1995-1, 6.67%, due 2025
Debt Instrument [Line Items]
Long Term Debt	$ 10,000	10,000
Less:
Interest rate	6.67%
Unsecured 6.75% Debentures, due 2028
Debt Instrument [Line Items]
Long Term Debt	$ 150,000	$ 150,000
Less:
Interest rate	6.75%

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Amount, after accumulated amortization, of debt discount (premium).

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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- Definition

Present value of lessee's discounted obligation for lease payments from finance lease.

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Amount of long-term debt and lease obligation, classified as noncurrent.

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Amount of long-term debt and lease obligation, including portion classified as current.

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