Capitalization And Short-Term Borrowings (Narrative) (Details) (USD $)	12 Months Ended								0 Months Ended				12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2012 Stock Options and SARs [Member]	Sep. 30, 2012 6.50% Notes Due April 2018 And 8.75% Notes Due May 2019 [Member]	Sep. 30, 2012 8.75% Notes Due In May 2019 [Member]	Sep. 30, 2012 6.50% Notes Mature In April 2018 [Member]	Sep. 30, 2011 6.70% Medium-Term Notes November 2011 [Member]	Dec. 01, 2011 4.90% Notes Due December 1, 2021 [Member]	Sep. 30, 2012 Indenture From 1974 [Member]	Sep. 30, 2012 Commercial Paper [Member]	Sep. 30, 2012 Notes Payable [Member]	Sep. 30, 2012 2013 [Member]	Sep. 30, 2012 2014 [Member]	Sep. 30, 2012 2014 [Member] Restricted Stock Units [Member]	Sep. 30, 2012 2015 [Member]	Sep. 30, 2012 2015 [Member] Restricted Stock Units [Member]	Sep. 30, 2012 2016 [Member]	Sep. 30, 2012 2016 [Member] Restricted Stock Units [Member]	Sep. 30, 2012 2017 [Member] Restricted Stock Units [Member]	Sep. 30, 2012 2018 [Member]	Sep. 30, 2012 2021 [Member]
Debt Instrument [Line Items]
Issue shares of common stock for the Direct Stock Purchase and Dividend Reinvestment Plan	155,310
Stock Issued During Period, Shares, Stock Options Exercised	476,243			465,894
Shares issued for restricted stock	41,525
Shares issued under retainer policy	15,755
Shares tendered	161,021
Percentage of voting power	10%
Equity redemption price per share	$ 0.005
Percentage of assets or earning power that are sold or transferred	50.00%
Voting power percentage to redeem rights	75.00%
Rights expiration date	July 31, 2018
Percentage of principal amount					101.00%				101.00%
Carrying Amount	$ 1,399,000,000	$ 1,049,000,000								$ 99,000,000
Long-term debt, face value						250,000,000	300,000,000		500,000,000
Long-term debt, interest rate	7.10%
Long-term debt, interest rate						8.75%	6.50%	6.70%	4.90%
Principal amounts of long-term debt maturing in 2013	250,000,000
Principal amounts of long-term debt maturing in 2014	0
Principal amounts of long-term debt maturing in 2015	0
Principal amounts of long-term debt maturing in 2016	0
Principal amounts of long-term debt maturing in 2017	0
Principal amounts of long-term debt maturing after 2017	1,149,000,000
Lines of credit aggregate value	335,000,000
Commercial paper	300,000,000
Line of Credit Facility, Maximum Borrowing Capacity	750,000,000
Commercial paper, outstanding	165,000,000	40,000,000
Weighted average interest rate		0.43%									0.50%	0.60%
Line of Credit Facility, Expiration Date	Jan. 06, 2017
Short-term notes payable outstanding	6,000,000
Committed credit facility debt to capitalization ratio	65.00%
Debt to capitalization ratio	44.00%
Additional borrowing	2,070,000,000
Maximum debt increase under existing indenture covenants	1,510,000,000
Aggregated indebtedness	40,000,000
Net proceeds from issuance of long-term debt	496,085,000	0	0						496,100,000
Current portion of long-term debt								$ 150,000,000
Preferred stock, shares authorized	10,000,000
Preferred stock par value	$ 1
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Lapse													34,582	34,601	12,932	32,852	35,300	5,000	35,301	22,367	35,000	20,000
Non-vested restricted stock lapse													34,582	34,601	12,932	32,852	35,300	5,000	35,301	22,367	35,000	20,000