Capitalization And Short-Term Borrowings (Narrative) (Details)				12 Months Ended
	Feb. 24, 2021 USD ($)	Jun. 03, 2020 USD ($)	Jun. 02, 2020 USD ($) $ / shares shares	Sep. 30, 2021 USD ($) $ / shares shares	Sep. 30, 2020 USD ($) $ / shares shares	Sep. 30, 2019 USD ($) $ / shares shares	Mar. 11, 2021 USD ($)
Debt Instrument [Line Items]
Issue shares of common stock for the Direct Stock Purchase and Dividend Reinvestment Plan | shares				0
Common stock issued for 401(k) plans | shares				0
Shares tendered | shares				83,288
Share-Based Payment Expense				$ 15,200,000	$ 13,100,000	$ 19,500,000
Tax benefit related to stock-based compensation expense				2,400,000	2,100,000	3,800,000
Capitalized stock-based compensation costs				100,000	100,000	100,000
Gain (Loss) on Extinguishment of Debt				(15,715,000)	0	0
Net proceeds from issuance of long-term debt				495,267,000	493,007,000	$ 0
Principal amounts of long-term debt maturing in 2022				0
Principal amounts of long-term debt maturing in 2023				549,000,000
Principal amounts of long-term debt maturing in 2024				0
Principal amounts of long-term debt maturing in 2025				500,000,000
Principal amounts of long-term debt maturing in 2026				500,000,000
Principal amounts of long-term debt maturing after 2026				1,100,000,000
Commercial paper, outstanding				158,500,000	15,000,000
Short-term notes payable outstanding				$ 0	$ 15,000,000
Committed credit facility maximum debt to capitalization ratio				0.65
Ceiling Test Impairment Adjustment				50.00%
Ceiling Test Impairment Maximum Adjustment				$ 250,000,000
Debt to capitalization ratio				0.59
Additional borrowing				$ 884,200,000
Aggregated indebtedness				40,000,000
Maximum debt increase under existing indenture covenants				$ 1,600,000,000
Preferred stock, shares authorized | shares				10,000,000
Preferred stock par value | $ / shares				$ 1
Percentage of Long-Term Debt issued under 1974 Indenture				3.70%
Common Stock, Par Value | $ / shares				$ 1	$ 1
Cumulative after-tax ceiling test impairments since July 1, 2018				$ 381,400,000
Committed Credit Facility Debt to Capitalization Ratio Ceiling Test Impairment Adjustment Amount				190,700,000
Tax expense related to stock-based compensation exercises and vestings				$ 700,000
Number of Shares available for future grant | shares				2,845,865
Maximum Long-Term Debt To Consolidated Asset Ratio under Indenture				60.00%
Indenture Period before Debt Issuance				15 months
Indenture Test Period				12 months
Notes Payable to Banks [Member]
Debt Instrument [Line Items]
Weighted average interest rate					1.51%
June 2, 2020 Public Offering of Common Stock [Member]
Debt Instrument [Line Items]
Common Stock Issued from Sale of Common Stock (Shares) | shares			4,370,000
Common Stock, Par Value | $ / shares			$ 1.00
Common Stock Issued, Price Per Share | $ / shares			$ 39.50
Proceeds from Issuance of Common Stock			$ 165,800,000
Stock Appreciation Rights (SARs) [Member]
Debt Instrument [Line Items]
Number of Shares Granted | shares				0	0	0
Total intrinsic value of SAR's exercised						$ 7,200,000
Number of Awards Vested | shares				0	0	0
Number of Awards Exercised | shares				0	0
Restricted Share Awards [Member]
Debt Instrument [Line Items]
Number of Shares Granted | shares				0	0	0
Weighted Average Fair Value per Award Granted | $ / shares				$ 0
Number of Awards Vested | shares				20,000
Non-Performance Based Restricted Stock Units (RSUs) [Member]
Debt Instrument [Line Items]
Number of Shares Granted | shares				172,513	150,839	123,939
Weighted Average Fair Value per Award Granted | $ / shares				$ 37.98	$ 40.38	$ 49.40
Number of Awards Vested | shares				106,007
Unrecognized compensation expense				$ 6,000,000
Unrecognized compensation expense recognized weighted average period				2 years
Performance Shares [Member]
Debt Instrument [Line Items]
Common stock issued | shares				165,161
Number of Shares Granted | shares				309,470	254,608	244,734
Weighted Average Fair Value per Award Granted | $ / shares				$ 39.19	$ 43.32	$ 55.67
Number of Awards Vested | shares				165,161
Unrecognized compensation expense				$ 8,500,000
Unrecognized compensation expense recognized weighted average period				1 year 8 months 12 days
Restricted Stock Units (RSUs) [Member]
Debt Instrument [Line Items]
Common stock issued | shares				106,007
Board Of Directors [Member]
Debt Instrument [Line Items]
Common stock issued | shares				38,973
5.50% Notes Due January 15, 2026 [Member]
Debt Instrument [Line Items]
Long-term debt, face value		$ 500,000,000
Long-term debt, interest rate		5.50%
Net proceeds from issuance of long-term debt		$ 493,000,000
Indenture From 1974 [Member]
Debt Instrument [Line Items]
Carrying Amount				$ 99,000,000
Commercial Paper [Member]
Debt Instrument [Line Items]
Commercial paper available				$ 500,000,000
Weighted average interest rate				0.40%	0.25%
2.95% Notes Due March 1, 2031 [Member]
Debt Instrument [Line Items]
Long-term debt, face value	$ 500,000,000
Long-term debt, interest rate	2.95%
Net proceeds from issuance of long-term debt	$ 495,300,000
4.90% Notes Due December 1, 2021 [Member]
Debt Instrument [Line Items]
Long-term debt, face value							$ 500,000,000
Long-term debt, interest rate							4.90%
Debt Instrument redeemed				$ 515,700,000
Gain (Loss) on Extinguishment of Debt				(15,700,000)
Fourth Amended & Restated Credit Agreement [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity				750,000,000
364-Day Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity				250,000,000
Line of Credit Facility Original Maximum Borrowing Capacity				$ 200,000,000
2022 [Member] | Non-Performance Based Restricted Stock Units (RSUs) [Member]
Debt Instrument [Line Items]
Non-vested stock-based compensation lapse | shares				119,225
2022 [Member] | Performance Shares [Member]
Debt Instrument [Line Items]
Non-vested stock-based compensation lapse | shares				165,438
2023 [Member] | Non-Performance Based Restricted Stock Units (RSUs) [Member]
Debt Instrument [Line Items]
Non-vested stock-based compensation lapse | shares				108,138
2023 [Member] | Performance Shares [Member]
Debt Instrument [Line Items]
Non-vested stock-based compensation lapse | shares				203,632
2024 [Member] | Non-Performance Based Restricted Stock Units (RSUs) [Member]
Debt Instrument [Line Items]
Non-vested stock-based compensation lapse | shares				83,618
2024 [Member] | Performance Shares [Member]
Debt Instrument [Line Items]
Non-vested stock-based compensation lapse | shares				231,564
2025 [Member] | Non-Performance Based Restricted Stock Units (RSUs) [Member]
Debt Instrument [Line Items]
Non-vested stock-based compensation lapse | shares				35,650
2026 [Member] | Non-Performance Based Restricted Stock Units (RSUs) [Member]
Debt Instrument [Line Items]
Non-vested stock-based compensation lapse | shares				18,850