Debt - Narrative (Details)				6 Months Ended
	Mar. 28, 2024 USD ($)	Mar. 27, 2024 USD ($)	Oct. 10, 2023 USD ($)	Mar. 31, 2024 USD ($) creditFacility	Mar. 31, 2023 USD ($)	Sep. 30, 2023 USD ($)
Line Of Credit Facility [Line Items]
Proceeds from issuance of long-term debt				$ 898,275,000	$ 797,258,000
Maximum debt-to-total-capitalization ratio				70.00%
Debt-to-total-capitalization ratio				0.40
Minimum
Line Of Credit Facility [Line Items]
Outstanding indebtedness				$ 15,000,000
Maximum
Line Of Credit Facility [Line Items]
Outstanding indebtedness				100,000,000
Unsecured Senior Notes Due October 2053 | Senior Notes
Line Of Credit Facility [Line Items]
Debt face amount			$ 500,000,000
Interest rate			6.20%
Effective rate			5.56%
Unsecured Senior Notes Due October 2033 | Senior Notes
Line Of Credit Facility [Line Items]
Debt face amount			$ 400,000,000
Interest rate			5.90%
Effective rate			4.35%
Unsecured Senior Notes Due October 2033 and Unsecured Senior Notes Due October 2053 | Senior Notes
Line Of Credit Facility [Line Items]
Proceeds from issuance of long-term debt			$ 889,400,000
Five Year Unsecured Revolving Credit Agreement
Line Of Credit Facility [Line Items]
Outstanding commercial paper						$ 241,900,000
Five Year Unsecured Revolving Credit Agreement | Commercial Paper
Line Of Credit Facility [Line Items]
Maximum borrowing capacity		$ 1,500,000,000
Debt agreement term		5 years
Five Year Unsecured Revolving Credit Agreement, March 28, 2029
Line Of Credit Facility [Line Items]
Outstanding commercial paper				$ 0
Five Year Unsecured Revolving Credit Agreement, March 28, 2029 | Minimum | Base Rate
Line Of Credit Facility [Line Items]
Interest rate spread				0.00%
Five Year Unsecured Revolving Credit Agreement, March 28, 2029 | Minimum | Term SOFR
Line Of Credit Facility [Line Items]
Interest rate spread				0.75%
Five Year Unsecured Revolving Credit Agreement, March 28, 2029 | Maximum | Base Rate
Line Of Credit Facility [Line Items]
Interest rate spread				0.25%
Five Year Unsecured Revolving Credit Agreement, March 28, 2029 | Maximum | Term SOFR
Line Of Credit Facility [Line Items]
Interest rate spread				1.25%
Five Year Unsecured Revolving Credit Agreement, March 28, 2029 | Commercial Paper
Line Of Credit Facility [Line Items]
Maximum borrowing capacity	$ 1,500,000,000			$ 1,500,000,000
Debt agreement term	5 years
Accordion feature				250,000,000
Maximum borrowing capacity post accordion feature				1,750,000,000
Five Year Unsecured Revolving Credit Agreement, March 28, 2029 | Revolving Credit Facility
Line Of Credit Facility [Line Items]
Maximum borrowing capacity				$ 3,100,000,000
Number of credit facilities | creditFacility				4
$900 Million Revolving Credit Facility | Revolving Credit Facility
Line Of Credit Facility [Line Items]
Maximum borrowing capacity		$ 900,000,000
Debt agreement term		3 years
Outstanding borrowings						0
$1.5 Billion Revolving Credit Facility | Revolving Credit Facility
Line Of Credit Facility [Line Items]
Maximum borrowing capacity	$ 1,500,000,000
Debt agreement term	3 years
Accordion feature				$ 250,000,000
Maximum borrowing capacity post accordion feature				1,750,000,000
Outstanding borrowings				$ 0
$1.5 Billion Revolving Credit Facility | Revolving Credit Facility | Minimum | Base Rate
Line Of Credit Facility [Line Items]
Interest rate spread				0.00%
$1.5 Billion Revolving Credit Facility | Revolving Credit Facility | Minimum | Term SOFR
Line Of Credit Facility [Line Items]
Interest rate spread				0.75%
$1.5 Billion Revolving Credit Facility | Revolving Credit Facility | Maximum | Base Rate
Line Of Credit Facility [Line Items]
Interest rate spread				0.25%
$1.5 Billion Revolving Credit Facility | Revolving Credit Facility | Maximum | Term SOFR
Line Of Credit Facility [Line Items]
Interest rate spread				1.25%
$50 Million Bank Loan Agreement | Line of Credit
Line Of Credit Facility [Line Items]
Maximum borrowing capacity				$ 50,000,000
Debt agreement term				364 days
Outstanding borrowings				$ 0		$ 0
$50 Million Revolving Credit Facility
Line Of Credit Facility [Line Items]
Outstanding borrowings				0
$50 Million Revolving Credit Facility | Revolving Credit Facility
Line Of Credit Facility [Line Items]
Maximum borrowing capacity				$ 50,000,000
Debt agreement term				364 days
Remaining borrowing capacity				$ 44,400,000