Borrowings (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended																						12 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended															3 Months Ended	9 Months Ended	12 Months Ended																	9 Months Ended	12 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2013	Jul. 31, 2012	Oct. 31, 2012	Jul. 31, 2013 U.S. Dollar Global Notes	Oct. 31, 2012 U.S. Dollar Global Notes	Jul. 31, 2013 2006 Shelf Registration Statement-$500 issued at discount to par at a price of 99.694% in February 2007 at 5.4%, due March 2017	Oct. 31, 2012 2006 Shelf Registration Statement-$500 issued at discount to par at a price of 99.694% in February 2007 at 5.4%, due March 2017	Oct. 31, 2012 2006 Shelf Registration Statement-$1,500 issued at discount to par at a price of 99.921% in March 2008 at 4.5%, paid March 2013	Jul. 31, 2013 2006 Shelf Registration Statement-$750 issued at discount to par at a price of 99.932% in March 2008 at 5.5%, due March 2018	Oct. 31, 2012 2006 Shelf Registration Statement-$750 issued at discount to par at a price of 99.932% in March 2008 at 5.5%, due March 2018	Jul. 31, 2013 2006 Shelf Registration Statement-$2,000 issued at discount to par at a price of 99.561% in December 2008 at 6.125%, due March 2014	Oct. 31, 2012 2006 Shelf Registration Statement-$2,000 issued at discount to par at a price of 99.561% in December 2008 at 6.125%, due March 2014	Jul. 31, 2013 2006 Shelf Registration Statement-$1,500 issued at discount to par at a price of 99.993% in February 2009 at 4.75%, due June 2014	Oct. 31, 2012 2006 Shelf Registration Statement-$1,500 issued at discount to par at a price of 99.993% in February 2009 at 4.75%, due June 2014	Jul. 31, 2013 2009 Shelf Registration Statement-$1,100 issued at discount to par at a price of 99.921% in September 2010 at 1.25% due September 2013	Oct. 31, 2012 2009 Shelf Registration Statement-$1,100 issued at discount to par at a price of 99.921% in September 2010 at 1.25% due September 2013	Jul. 31, 2013 2009 Shelf Registration Statement-$1,100 issued at discount to par at a price of 99.887% in September 2010 at 2.125% due September 2015	Oct. 31, 2012 2009 Shelf Registration Statement-$1,100 issued at discount to par at a price of 99.887% in September 2010 at 2.125% due September 2015	Jul. 31, 2013 2009 Shelf Registration Statement-$650 issued at discount to par at a price of 99.911% in December 2010 at 2.2% due December 2015	Oct. 31, 2012 2009 Shelf Registration Statement-$650 issued at discount to par at a price of 99.911% in December 2010 at 2.2% due December 2015	Jul. 31, 2013 2009 Shelf Registration Statement-$1,350 issued at discount to par at a price of 99.827% in December 2010 at 3.75% due December 2020	Oct. 31, 2012 2009 Shelf Registration Statement-$1,350 issued at discount to par at a price of 99.827% in December 2010 at 3.75% due December 2020	Oct. 31, 2012	Jul. 31, 2013	Jul. 31, 2013	Oct. 31, 2012	Jul. 31, 2013 2009 Shelf Registration Statement-$500 issued at discount to par at a price of 99.971% in May 2011 at 1.55%, due May 2014	Oct. 31, 2012 2009 Shelf Registration Statement-$500 issued at discount to par at a price of 99.971% in May 2011 at 1.55%, due May 2014	Jul. 31, 2013 2009 Shelf Registration Statement-$1,000 issued at discount to par at a price of 99.958% in May 2011 at 2.65%, due June 2016	Oct. 31, 2012 2009 Shelf Registration Statement-$1,000 issued at discount to par at a price of 99.958% in May 2011 at 2.65%, due June 2016	Jul. 31, 2013 2009 Shelf Registration Statement-$1,250 issued at discount to par at a price of 99.799% in May 2011 at 4.3%, due June 2021	Oct. 31, 2012 2009 Shelf Registration Statement-$1,250 issued at discount to par at a price of 99.799% in May 2011 at 4.3%, due June 2021	Jul. 31, 2013 2009 Shelf Registration Statement-$750 issued at discount to par at a price of 99.977% in September 2011 at 2.35%, due March 2015	Oct. 31, 2012 2009 Shelf Registration Statement-$750 issued at discount to par at a price of 99.977% in September 2011 at 2.35%, due March 2015	Jul. 31, 2013 2009 Shelf Registration Statement-$1,300 issued at discount to par at a price of 99.784% in September 2011 at 3.0%, due September 2016	Oct. 31, 2012 2009 Shelf Registration Statement-$1,300 issued at discount to par at a price of 99.784% in September 2011 at 3.0%, due September 2016	Jul. 31, 2013 2009 Shelf Registration Statement-$1,000 issued at discount to par at a price of 99.816% in September 2011 at 4.375%, due September 2021	Oct. 31, 2012 2009 Shelf Registration Statement-$1,000 issued at discount to par at a price of 99.816% in September 2011 at 4.375%, due September 2021	Jul. 31, 2013 2009 Shelf Registration Statement-$1,200 issued at discount to par at a price of 99.863% in September 2011 at 6.0% due September 2041	Oct. 31, 2012 2009 Shelf Registration Statement-$1,200 issued at discount to par at a price of 99.863% in September 2011 at 6.0% due September 2041	Jul. 31, 2013	Jul. 31, 2013	Oct. 31, 2012	Jul. 31, 2013 2009 Shelf Registration Statement-$650 issued at discount to par at a price of 99.946% in December 2011 at 2.625%, due December 2014	Oct. 31, 2012 2009 Shelf Registration Statement-$650 issued at discount to par at a price of 99.946% in December 2011 at 2.625%, due December 2014	Jul. 31, 2013 2009 Shelf Registration Statement-$850 issued at discount to par at a price of 99.790% in December 2011 at 3.3%, due December 2016	Oct. 31, 2012 2009 Shelf Registration Statement-$850 issued at discount to par at a price of 99.790% in December 2011 at 3.3%, due December 2016	Jul. 31, 2013 2009 Shelf Registration Statement-$1,500 issued at discount to par at a price of 99.707% in December 2011 at 4.65%, due December 2021	Oct. 31, 2012 2009 Shelf Registration Statement-$1,500 issued at discount to par at a price of 99.707% in December 2011 at 4.65%, due December 2021	Jul. 31, 2013 2009 Shelf Registration Statement-$1,500 issued at discount to par at a price of 99.985% in March 2012 at 2.6%, due September 2017	Oct. 31, 2012 2009 Shelf Registration Statement-$1,500 issued at discount to par at a price of 99.985% in March 2012 at 2.6%, due September 2017	Jul. 31, 2013 2009 Shelf Registration Statement-$500 issued at discount to par at a price of 99.771% in March 2012 at 4.05%, due September 2022	Oct. 31, 2012 2009 Shelf Registration Statement-$500 issued at discount to par at a price of 99.771% in March 2012 at 4.05%, due September 2022	Jul. 31, 2013 EDS Senior Notes	Oct. 31, 2012 EDS Senior Notes	Jul. 31, 2013 EDS Senior Notes-$1,100 issued June 2003 at 6.0%, paid August 2013	Oct. 31, 2012 EDS Senior Notes-$1,100 issued June 2003 at 6.0%, paid August 2013	Jul. 31, 2013 EDS Senior Notes-$300 issued October 1999 at 7.45%, due October 2029	Oct. 31, 2012 EDS Senior Notes-$300 issued October 1999 at 7.45%, due October 2029	Jul. 31, 2013 Other, including capital lease obligations, at 0.00%-8.39%, due in calendar years 2014-2024	Oct. 31, 2012 Other, including capital lease obligations, at 0.00%-8.39%, due in calendar years 2014-2024	Jul. 31, 2013 Other, including capital lease obligations, at 0.00%-8.39%, due in calendar years 2014-2024 HPFS and its subsidiaries	Oct. 31, 2012 Other, including capital lease obligations, at 0.00%-8.39%, due in calendar years 2014-2024 HPFS and its subsidiaries
Long-term debt
Balance outstanding						$ 21,783	$ 25,031	$ 499	$ 499	$ 1,500	$ 750	$ 750	$ 1,999	$ 1,998	$ 1,500	$ 1,500	$ 1,100	$ 1,100	$ 1,100	$ 1,100	$ 650	$ 650	$ 1,348	$ 1,348	$ 1,750	$ 500	$ 500	$ 500	$ 500	$ 500	$ 1,000	$ 1,000	$ 1,248	$ 1,248	$ 750	$ 750	$ 1,298	$ 1,298	$ 999	$ 998	$ 1,198	$ 1,198	$ 350	$ 350	$ 350	$ 650	$ 650	$ 849	$ 849	$ 1,496	$ 1,496	$ 1,500	$ 1,500	$ 499	$ 499	$ 1,414	$ 1,423	$ 1,100	$ 1,109	$ 314	$ 314
Other, including capital lease obligations																																																														710	680	257	225
Fair value adjustment related to hedged debt	124		124		399
Less: current portion	(6,907)		(6,907)		(5,744)
Total long-term debt	17,124		17,124		21,789
Discount to par (as a percent)								99.694%	99.694%	99.921%	99.932%	99.932%	99.561%	99.561%	99.993%	99.993%	99.921%	99.921%	99.887%	99.887%	99.911%	99.911%	99.827%	99.827%					99.971%	99.971%	99.958%	99.958%	99.799%	99.799%	99.977%	99.977%	99.784%	99.784%	99.816%	99.816%	99.863%	99.863%				99.946%	99.946%	99.79%	99.79%	99.707%	99.707%	99.985%	99.985%	99.771%	99.771%
Interest rate (as a percent)								5.40%	5.40%	4.50%	5.50%	5.50%	6.125%	6.125%	4.75%	4.75%	1.25%	1.25%	2.125%	2.125%	2.20%	2.20%	3.75%	3.75%					1.55%	1.55%	2.65%	2.65%	4.30%	4.30%	2.35%	2.35%	3.00%	3.00%	4.375%	4.375%	6.00%	6.00%				2.625%	2.625%	3.30%	3.30%	4.65%	4.65%	2.60%	2.60%	4.05%	4.05%			6.00%	6.00%	7.45%	7.45%
Face amount of debt instrument								500	500	1,500	750	750	2,000	2,000	1,500	1,500	1,100	1,100	1,100	1,100	650	650	1,350	1,350	1,750	500	500	500	500	500	1,000	1,000	1,250	1,250	750	750	1,300	1,300	1,000	1,000	1,200	1,200	350	350	350	650	650	850	850	1,500	1,500	1,500	1,500	500	500			1,100	1,100	300	300
Reference interest rate																									three-month USD LIBOR	three-month USD LIBOR	three-month USD LIBOR	three-month USD LIBOR															three-month USD LIBOR	three-month USD LIBOR	three-month USD LIBOR
Spread on reference interest rate (as a percent)																									0.28%	0.40%	0.40%	0.40%															1.55%	1.55%	1.55%
Minimum interest rate (as a percent)																																																														0.00%	0.00%
Maximum interest rate (as a percent)																																																														8.39%	8.39%
Borrowings collateralized by certain financing receivable assets																																																														234	225
Interest expense on borrowings
Financing interest	77	80	238	238
Interest expense	107	141	332	379
Total interest expense	$ 184	$ 221	$ 570	$ 617