Capitalization And Short-Term Borrowings (Narrative) (Details)		3 Months Ended	12 Months Ended
	Jun. 25, 2015 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) $ / shares shares	Sep. 30, 2015 USD ($) $ / shares shares	Sep. 30, 2014 USD ($) $ / shares shares
Debt Instrument [Line Items]
Issue shares of common stock for the Direct Stock Purchase and Dividend Reinvestment Plan | shares			147,056
Common stock issued for 401(k) plans | shares			118,864
Common stock shares issued due to stock option and SARs exercises | shares			(287,500)
Shares tendered | shares			88,675
Percentage of voting power			10.00%
Percentage of assets or earning power that are sold or transferred			50.00%
Equity redemption price per share | $ / shares			$ 0.005
Voting power percentage to redeem rights			75.00%
Rights expiration date			Jul. 31, 2018
Share-Based Payment Expense			$ 4,800,000	$ 2,100,000	$ 10,500,000
Tax benefit related to stock-based compensation expense			1,900,000	900,000	4,300,000
Capitalized stock-based compensation costs			100,000	100,000	100,000
Tax benefit realized from exercise of stock-based compensation			1,600,000	7,700,000	3,100,000
Tax benefit recorded from exercise of stock-based compensation			1,900,000	9,100,000	4,600,000
Reversal of Stock-Based Compensation Expense		$ 8,000,000	8,000,000
Carrying Amount		2,084,009,000	$ 2,086,252,000	2,084,009,000
Percentage of Long-Term Debt issued under 1974 Indenture			4.70%
Net proceeds from issuance of long-term debt			$ 0	444,635,000	0
Principal amounts of long-term debt maturing in 2017			0
Principal amounts of long-term debt maturing in 2018			300,000,000
Principal amounts of long-term debt maturing in 2019			250,000,000
Principal amounts of long-term debt maturing in 2020			0
Principal amounts of long-term debt maturing in 2021			0
Principal amounts of long-term debt maturing after 2021			1,549,000,000
Commercial paper available			500,000,000
Commercial paper, outstanding		0	$ 0	0
Line of Credit Facility, Term Start Date			Oct. 01, 2017
Short-term notes payable outstanding		$ 0	$ 0	0
Debt to capitalization ratio			0.58
Additional borrowing			$ 1,080,000,000
Aggregated indebtedness			$ 40,000,000
Preferred stock, shares authorized | shares			10,000,000
Preferred stock par value | $ / shares			$ 1
Committed credit facility, outstanding amount			$ 0
Stock Options And SARs [Member]
Debt Instrument [Line Items]
Common stock shares issued due to stock option and SARs exercises | shares			293,841
Stock Options [Member]
Debt Instrument [Line Items]
Options, exercises in period, total intrinsic value			$ 4,100,000	5,100,000	13,700,000
Proceeds from Stock Options Exercised			$ 8,000,000	$ 5,600,000	$ 7,400,000
Stock Appreciation Rights (SARs) [Member]
Debt Instrument [Line Items]
Number of Shares Forfeited | shares			0
Number of Shares Granted | shares			0	0	0
Total intrinsic value of SAR's exercised			$ 400,000	$ 2,000,000	$ 8,400,000
Number of Awards Vested | shares			113,082	157,386	323,188
Equity instruments other than options, vested in period, total fair value			$ 1,200,000	$ 1,700,000	$ 3,800,000
Unrecognized compensation expense			$ 100,000
Unrecognized compensation expense recognized weighted average period			7 months
Restricted Share Awards [Member]
Debt Instrument [Line Items]
Number of Shares Forfeited | shares			35,000
Number of Shares Granted | shares			0	0	0
Weighted Average Fair Value per Award Granted | $ / shares			$ 0.00
Number of Awards Vested | shares			5,000
Unrecognized compensation expense			$ 300,000
Unrecognized compensation expense recognized weighted average period			2 years 7 months 17 days
Non-Performance Based Restricted Stock Units (RSUs) [Member]
Debt Instrument [Line Items]
Number of Shares Forfeited | shares			29,507
Number of Shares Granted | shares			101,943	88,899	82,151
Weighted Average Fair Value per Award Granted | $ / shares			$ 35.89	$ 64.04	$ 65.24
Number of Awards Vested | shares			70,233
Unrecognized compensation expense			$ 4,500,000
Unrecognized compensation expense recognized weighted average period			1 year 7 months 13 days
Performance Based Restricted Stock Units (RSUs) [Member]
Debt Instrument [Line Items]
Number of Shares Forfeited | shares			0
Number of Shares Granted | shares			0	0	0
Weighted Average Fair Value per Award Granted | $ / shares			$ 0.00
Number of Awards Vested | shares			0
Unrecognized compensation expense			$ 0
Performance Shares [Member]
Debt Instrument [Line Items]
Number of Shares Forfeited | shares			76,504
Number of Shares Granted | shares			309,996	107,044	116,090
Weighted Average Fair Value per Award Granted | $ / shares			$ 30.71	$ 65.26	$ 67.16
Number of Awards Vested | shares			0
Unrecognized compensation expense			$ 7,000,000
Unrecognized compensation expense recognized weighted average period			1 year 4 months 20 days
Restricted Stock Units (RSUs) [Member]
Debt Instrument [Line Items]
Common stock issued | shares			70,233
5.20% Notes Due July 2025 [Member]
Debt Instrument [Line Items]
Long-term debt, face value	$ 450,000,000
Long-term debt, interest rate	5.20%
Net proceeds from issuance of long-term debt	$ 444,600,000
Indenture From 1974 [Member]
Debt Instrument [Line Items]
Carrying Amount			$ 98,700,000
Board Of Directors [Member]
Debt Instrument [Line Items]
Common stock issued | shares			18,184
Third Amended & Restated Credit Agreement [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity			$ 750,000,000.0
364-Day Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity			$ 500,000,000
Last Day of Fiscal Quarter Through September 30, 2017 [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Expiration Date			Sep. 30, 2017
Committed credit facility debt to capitalization ratio			0.675
Last Day of Fiscal Quarter October 1, 2017 through December 5, 2019 [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Expiration Date			Dec. 05, 2019
Committed credit facility debt to capitalization ratio			0.65
2017 [Member] | Non-Performance Based Restricted Stock Units (RSUs) [Member]
Debt Instrument [Line Items]
Non-vested stock-based compensation lapse | shares			64,036
2017 [Member] | Performance Shares [Member]
Debt Instrument [Line Items]
Non-vested stock-based compensation lapse | shares			86,968
2018 [Member] | Non-Performance Based Restricted Stock Units (RSUs) [Member]
Debt Instrument [Line Items]
Non-vested stock-based compensation lapse | shares			44,817
2018 [Member] | Performance Shares [Member]
Debt Instrument [Line Items]
Non-vested stock-based compensation lapse | shares			89,192
2019 [Member] | Non-Performance Based Restricted Stock Units (RSUs) [Member]
Debt Instrument [Line Items]
Non-vested stock-based compensation lapse | shares			53,232
2019 [Member] | Performance Shares [Member]
Debt Instrument [Line Items]
Non-vested stock-based compensation lapse | shares			262,074
2020 [Member] | Non-Performance Based Restricted Stock Units (RSUs) [Member]
Debt Instrument [Line Items]
Non-vested stock-based compensation lapse | shares			43,757
2021 [Member] | Restricted Share Awards [Member]
Debt Instrument [Line Items]
Non-vested stock-based compensation lapse | shares			20,000
2021 [Member] | Non-Performance Based Restricted Stock Units (RSUs) [Member]
Debt Instrument [Line Items]
Non-vested stock-based compensation lapse | shares			33,309