Capitalization And Short-Term Borrowings (Summary Of Changes In Common Stock Equity) (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
		Sep. 30, 2021		Sep. 30, 2020	Sep. 30, 2019
Schedule of Capitalization [Line Items]
Beginning balance (shares)		90,954,696
Beginning balance		$ 1,004,158
Balance at Beginning of Year		991,630		$ 1,272,601	$ 1,098,900
Beginning balance		(114,757)		(52,155)
Net Income (Loss) Available for Common Stock		363,647		(123,772)	304,290
Dividends Declared on Common Stock		(164,102)		(156,249)	(148,432)
Other Comprehensive Income (Loss), Net of Tax		(398,840)		(62,602)	15,595
Share-Based Payment Expense		$ 15,200		$ 13,100	19,500
Ending balance (Shares)		91,181,549		90,954,696
Ending balance		$ 1,017,446		$ 1,004,158
Balance at End of Year		1,191,175		991,630	1,272,601
Ending balance		$ (513,597)		$ (114,757)	$ (52,155)
Dividend per share		$ 1.8		$ 1.76	$ 1.72
Accumulated earnings free from limitations		$ 1,000,000
Common Stock [Member]
Schedule of Capitalization [Line Items]
Beginning balance (shares)		90,955,000		86,315,000	85,957,000
Beginning balance (value)		$ 90,955		$ 86,315	$ 85,957
Common Stock Issued from Sale of Common Stock (Shares)				4,370,000
Common Stock Issued from Sale of Common Stock (Value)				$ 4,370
Common Stock Issued Under Stock and Benefit Plans (Shares)		227,000		270,000	358,000
Common Stock Issued Under Stock and Benefit Plans (Value)		$ 227		$ 270	$ 358
Ending balance (Shares)		91,182,000		90,955,000	86,315,000
Ending balance (Value)		$ 91,182		$ 90,955	$ 86,315
Paid In Capital [Member]
Schedule of Capitalization [Line Items]
Beginning balance		1,004,158		832,264	820,223
Share-Based Payment Expense	[1]	15,297		13,180	19,613
Common Stock Issued from Sale of Common Stock (Value)				161,399
Stock Repurchased under Stock and Benefit Plans		(2,009)		(2,685)	(7,572)
Ending balance		1,017,446		1,004,158	832,264
Earnings Reinvested In The Business [Member]
Schedule of Capitalization [Line Items]
Balance at Beginning of Year		991,630		1,272,601	1,098,900
Net Income (Loss) Available for Common Stock		363,647		(123,772)	304,290
Dividends Declared on Common Stock		(164,102)		(156,249)	(148,432)
Balance at End of Year		1,191,175	[2]	991,630	1,272,601
Accumulated Other Comprehensive Income (Loss) [Member]
Schedule of Capitalization [Line Items]
Beginning balance		(114,757)		(52,155)	(67,750)
Other Comprehensive Income (Loss), Net of Tax		(398,840)		(62,602)	15,595
Ending balance		(513,597)		(114,757)	(52,155)
Guidance for Recognition and Measurement of Financial Assets and Liabilities [Member] | Cumulative Effect of Adoption of Authoritative Guidance [Member]
Schedule of Capitalization [Line Items]
Balance at Beginning of Year		0		0	7,437
Balance at End of Year				0	0
Guidance for Recognition and Measurement of Financial Assets and Liabilities [Member] | Earnings Reinvested In The Business [Member] | Cumulative Effect of Adoption of Authoritative Guidance [Member]
Schedule of Capitalization [Line Items]
Balance at Beginning of Year					7,437
Guidance for Reclassification of Stranded Tax Effects [Member] | Cumulative Effect of Adoption of Authoritative Guidance [Member]
Schedule of Capitalization [Line Items]
Balance at Beginning of Year		0		0	10,406
Balance at End of Year				0	0
Guidance for Reclassification of Stranded Tax Effects [Member] | Earnings Reinvested In The Business [Member] | Cumulative Effect of Adoption of Authoritative Guidance [Member]
Schedule of Capitalization [Line Items]
Balance at Beginning of Year					10,406
Guidance for Hedging [Member] | Cumulative Effect of Adoption of Authoritative Guidance [Member]
Schedule of Capitalization [Line Items]
Balance at Beginning of Year		$ 0		(950)	0
Balance at End of Year				0	(950)
Guidance for Hedging [Member] | Earnings Reinvested In The Business [Member] | Cumulative Effect of Adoption of Authoritative Guidance [Member]
Schedule of Capitalization [Line Items]
Balance at Beginning of Year				$ (950)
Balance at End of Year					$ (950)

[1] Paid in Capital includes compensation costs associated with performance shares and/or restricted stock awards. The expense is included within Net Income Available for Common Stock, net of tax benefits.

[2] The availability of consolidated earnings reinvested in the business for dividends payable in cash is limited under terms of the indentures covering long-term debt. At September 30, 2021, $1.0 billion of accumulated earnings was free of such limitations.