Short Term Debt Instruments (Details) (USD $)	3 Months Ended	9 Months Ended
	Jul. 31, 2014	Jul. 31, 2014	Oct. 31, 2013
Line Of Credit Facility [Line Items]
Credit Facility Current Borrowing Capacity	$ 850,000,000	$ 850,000,000
Maximum Facility	850,000,000	850,000,000
Letter Of Credit [Member]
Line Of Credit Facility [Line Items]
Credit Facility Current Borrowing Capacity	10,000,000	10,000,000	10,000,000
Letters of Credit Outstanding, Amount	1,800,000	1,800,000	2,100,000
Revolving Credit Facility [Member]
Line Of Credit Facility [Line Items]
Credit Facility Current Borrowing Capacity	850,000,000	850,000,000
Line Of Credit Commitment Annual Fee		$35,000 plus 8.5 basis points
Line of Credit Facility, Commitment Fee Amount		35,000
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage		0.085%
Line Of Credit Facility Frequency Of Commitment Fee Payment		Annual
Credit Facility Interest Rate Description		30-day LIBOR rate plus from 75 to 125 basis points
Credit Facility Covenant Terms		total debt to total capitalization of no greater than 70%
Credit Facility Covenant Compliance		actual ratio was 56%
Line of Credit Facility, Expiration Date		Oct. 01, 2017
Debt Covenant Total Debt To Total Capital Ratio		70.00%
Ratio Of Total Debt To Total Capital	56.00%	56.00%
Revolving Credit Facility [Member] | Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line Of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate		0.75%
Revolving Credit Facility [Member] | Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line Of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.25%
Commercial Paper [Member]
Line Of Credit Facility [Line Items]
Credit Facility Interest Rate Description		among other things, the size and maturity date of the note, the frequency of the issuance and our credit ratings, plus a spread of 5 basis points
Commercial Paper	490,000,000	490,000,000	400,000,000
Weighted Average Interest Rate	0.17%	0.17%
Credit Facility Minimum Amount Outstanding During Period	330,000,000	325,000,000
Credit Facility Maximum Amount Outstanding During Period	$ 495,000,000	$ 625,000,000
Short Term Borrowings Term		$850 million unsecured commercial paper (CP) program that is backstopped by the revolving syndicated credit facility. The amounts outstanding under the revolving syndicated credit facility and the CP program, either individually or in the aggregate, cannot exceed $850 million. The notes issued under the CP program may have maturities not to exceed 397 days from the date of issuance and bear interest based on, among other things, the size and maturity date of the note, the frequency of the issuance and our credit ratings, plus a spread of 5 basis points. Any borrowings under the CP program rank equally with our other unsubordinated and unsecured debt.
Commercial Paper [Member] | Base Rate [Member]
Line Of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate		0.05%
Commercial Paper [Member] | Minimum [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility Interest Rate During Period	0.11%	0.10%
Number Days Outstanding From Issuance Until Maturity Commercial Paper	7 days
Commercial Paper [Member] | Maximum [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility Interest Rate During Period	0.18%	0.43%
Number Days Outstanding From Issuance Until Maturity Commercial Paper	60 days
Commercial Paper [Member] | Weighted Average [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility Interest Rate During Period	0.16%	0.20%