Postretirement Benefits - Defined Benefit Plans (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		12 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2014 Pension Plan, Defined Benefit [Member]	Jul. 31, 2013 Pension Plan, Defined Benefit [Member]	Jul. 31, 2014 Pension Plan, Defined Benefit [Member]	Jul. 31, 2013 Pension Plan, Defined Benefit [Member]	Jul. 31, 2014 Other Postretirement Benefit Plan, Defined Benefit [Member]	Jul. 31, 2013 Other Postretirement Benefit Plan, Defined Benefit [Member]	Jul. 31, 2014 Other Postretirement Benefit Plan, Defined Benefit [Member]	Jul. 31, 2013 Other Postretirement Benefit Plan, Defined Benefit [Member]	Oct. 31, 1993 Other Pension Plan, Postretirement or Supplemental Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contractual termination benefits					$ 14	$ 0	$ 14	$ 0	$ 0	$ 0	$ 0	$ 0
Amounts contributed to meet regulatory funding requirements					33	29	98	86
Defined Contribution Plan, Cost Recognized	6	8	21	23
Contribution to the Supplemental Trust shares													25.5
Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year			$ 66