Capitalization (Narrative) (Details) $ in Millions	3 Months Ended
	Dec. 31, 2023 USD ($) shares	Feb. 26, 2027 USD ($)	Sep. 30, 2023 USD ($)	Feb. 28, 2022 USD ($) bank
Debt Instrument [Line Items]
Shares tendered (in shares)	77,094
Current Portion of Long-Term Debt | $	$ 0.0		$ 0.0
Credit Agreement
Debt Instrument [Line Items]
Number of banks In syndicate | bank				12
Maximum borrowing capacity | $				$ 1,000.0
Credit Agreement | Forecast
Debt Instrument [Line Items]
Maximum borrowing capacity | $		$ 940.0
Restricted Stock Units
Debt Instrument [Line Items]
Common stock issued (in shares)	111,832
Performance Shares
Debt Instrument [Line Items]
Common stock issued (in shares)	251,255
Board Of Directors
Debt Instrument [Line Items]
Common stock issued (in shares)	9,128
Officer DCP Plan
Debt Instrument [Line Items]
Common stock issued (in shares)	1,055