Shareholders' Equity - Narrative (Details) - USD ($)	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020	Oct. 03, 2022	Mar. 23, 2022	Jun. 29, 2021	Oct. 01, 2020
Class of Stock [Line Items]
Forward sales equity agreement, settlement in cash	$ 776,643,000
Net proceeds from equity offering	776,805,000	$ 606,667,000	$ 624,302,000
Senior Notes | Unsecured 1.50% Senior Notes, Due 2031
Class of Stock [Line Items]
Debt face amount							$ 600,000,000
Senior Notes | Unsecured 1.50% Senior Notes, Due 2031 | Subsequent Event
Class of Stock [Line Items]
Debt face amount				$ 800,000,000
Shelf Registration Statement
Class of Stock [Line Items]
Debt and equity securities authorized for issuance						$ 5,000,000,000
Debt and equity securities authorized for issuance value remaining	$ 2,200,000,000
Shelf Registration Statement | Subsequent Event
Class of Stock [Line Items]
Debt and equity securities authorized for issuance value remaining				$ 1,400,000,000
At-The-Market
Class of Stock [Line Items]
Value of shares authorized for issuance					$ 1,000,000,000
Forward sales equity agreement, shares (in shares)	11,862,319
Forward sales equity agreement, settlement in cash	$ 1,300,000,000
Shares issued (in shares)	7,907,883
Net proceeds from equity offering	$ 776,800,000
Value of shares available for issuance	$ 481,700,000