Stockholders' Deficit (Details) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended	3 Months Ended		9 Months Ended		1 Months Ended					1 Months Ended		1 Months Ended			3 Months Ended			3 Months Ended
	Jun. 30, 2012	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2013	Jul. 31, 2012	Sep. 30, 2011 Maximum [Member]	Nov. 30, 2011 Accelerated Share Repurchases Program [Member]	Oct. 31, 2011 Accelerated Share Repurchases Program [Member]	Oct. 31, 2011 October 2011 [Member]	Jan. 31, 2012 October 2011 [Member]	Oct. 31, 2011 October 2011 [Member] Accelerated Share Repurchases Program [Member]	Jan. 31, 2012 November 2011 [Member]	Nov. 30, 2011 November 2011 [Member] Accelerated Share Repurchases Program [Member]	Jan. 31, 2012 Open Market Share Repurchase Program [Member]	Oct. 31, 2011 Open Market Share Repurchase Program [Member]	Apr. 30, 2012 Open Market Share Repurchase Program [Member]	Jan. 31, 2012 Open Market Share Repurchase Program [Member]	Jul. 31, 2013 Preferred Stock [Member]	Jan. 31, 2013 Common Stock [Member]	Oct. 31, 2012 Common Stock [Member]	Jul. 31, 2013 Common Stock [Member]
Class of Stock [Line Items]
Common stock, dividends, declared per share	1
Ownership Percentage Stockholder Rights Plan				20.00%
Number of securities called by each right																		0.001			1
Exercise Price of Stockholder Rights Plan																		140
Redeemable amount per right under Shareholder Rights Plan				0.001
Stock Issued During Period, Shares, New Issues																			763,534	10,666,666
Share Price																			$ 18.75	$ 18.75
Proceeds from Issuance of Common Stock		$ 14	$ 192	$ 14	$ 0
Stock Repurchase Program, Authorized Amount						175		100							75
Treasury Stock, Shares, Acquired							2,542,609				2,380,952			1,905,600
Payments for Repurchase of Common Stock				0	75											5	70
Accelerated Share Repurchases, Settlement Payment or Receipt										80		20
Accelerated Share Repurchases, Initial Price Paid Per Share									$ 33.60
Stock Repurchase Program, Remaining Authorized Repurchase Amount								$ 20
Treasury Stock, Additional Shares Acquired													161,657