Borrowings (Details 2) - USD ($)	1 Months Ended	3 Months Ended		12 Months Ended
	Jan. 31, 2014	Jan. 31, 2016	Jan. 31, 2015	Oct. 31, 2015	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	May. 31, 2011	Dec. 31, 2010	Mar. 31, 2008	Feb. 28, 2007
Long-term debt
Total		$ 6,683,000,000		$ 6,677,000,000
Fair value adjustment related to hedged debt		79,000,000		103,000,000
Less: current portion of long-term debt		(20,000,000)		(2,160,000,000)
Interest expense on borrowings recognized in Consolidated Statements of Earnings
Interest expense		74,000,000	$ 67,000,000
U.S. Dollar Global Notes
Long-term debt
Total		$ 6,492,000,000		8,638,000,000
2006 Shelf Registration Statement- $500 issued at discount to par at a price of 99.694% in February 2007 at 5.4%, paid November 2015
Long-term debt
Total				$ 162,000,000
Discount to par (as a percent)		99.694%		99.694%							99.694%
Interest rate (as a percent)		5.40%		5.40%							5.40%
Face amount of debt instrument		$ 500,000,000		$ 500,000,000							$ 500,000,000
2006 Shelf Registration Statement- $750 issued at discount to par at a price of 99.932% in March 2008 at 5.5%, paid November 2015
Long-term debt
Total				$ 283,000,000
Discount to par (as a percent)		99.932%		99.932%						99.932%
Interest rate (as a percent)		5.50%		5.50%						5.50%
Face amount of debt instrument		$ 750,000,000		$ 750,000,000						$ 750,000,000
2009 Shelf Registration Statement- $650 issued at discount to par at a price of 99.911% in December 2010 at 2.2%, paid November 2015
Long-term debt
Total				$ 309,000,000
Discount to par (as a percent)		99.911%		99.911%					99.911%
Interest rate (as a percent)		2.20%		2.20%					2.20%
Face amount of debt instrument		$ 650,000,000		$ 650,000,000					$ 650,000,000
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
Long-term debt
Total		$ 648,000,000		$ 648,000,000
Discount to par (as a percent)		99.827%		99.827%					99.827%
Interest rate (as a percent)		3.75%		3.75%					3.75%
Face amount of debt instrument		$ 1,350,000,000		$ 1,350,000,000					$ 1,350,000,000
2009 Shelf Registration Statement- $1,000 issued at discount to par at a price of 99.958% in May 2011 at 2.65%, paid November 2015
Long-term debt
Total				$ 346,000,000
Discount to par (as a percent)				99.958%				99.958%
Interest rate (as a percent)				2.65%				2.65%
Face amount of debt instrument				$ 1,000,000,000				$ 1,000,000,000
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
Long-term debt
Total		$ 1,248,000,000		$ 1,248,000,000
Discount to par (as a percent)		99.799%		99.799%				99.799%
Interest rate (as a percent)		4.30%		4.30%				4.30%
Face amount of debt instrument		$ 1,250,000,000		$ 1,250,000,000				$ 1,250,000,000
2009 Shelf Registration Statement- $1,300 issued at discount to par at a price of 99.784% in September 2011 at 3.0%, paid November 2015
Long-term debt
Total				$ 390,000,000
Discount to par (as a percent)				99.784%			99.784%
Interest rate (as a percent)				3.00%			3.00%
Face amount of debt instrument				$ 1,300,000,000			$ 1,300,000,000
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
Long-term debt
Total		$ 999,000,000		$ 999,000,000
Discount to par (as a percent)		99.816%		99.816%			99.816%
Interest rate (as a percent)		4.375%		4.375%			4.375%
Face amount of debt instrument		$ 1,000,000,000		$ 1,000,000,000			$ 1,000,000,000
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
Long-term debt
Total		$ 1,199,000,000		$ 1,199,000,000
Discount to par (as a percent)		99.863%		99.863%			99.863%
Interest rate (as a percent)		6.00%		6.00%			6.00%
Face amount of debt instrument		$ 1,200,000,000		$ 1,200,000,000			$ 1,200,000,000
2009 Shelf Registration Statement- $850 issued at discount to par at a price of 99.790% in December 2011 at 3.3%, paid November 2015
Long-term debt
Total				$ 220,000,000
Discount to par (as a percent)				99.79%		99.79%
Interest rate (as a percent)				3.30%		3.30%
Face amount of debt instrument				$ 850,000,000		$ 850,000,000
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
Long-term debt
Total		$ 1,497,000,000		$ 1,497,000,000
Discount to par (as a percent)		99.707%		99.707%		99.707%
Interest rate (as a percent)		4.65%		4.65%		4.65%
Face amount of debt instrument		$ 1,500,000,000		$ 1,500,000,000		$ 1,500,000,000
2009 Shelf Registration Statement- $1,500 issued at discount to par at a price of 99.985% in March 2012 at 2.6%, paid November 2015
Long-term debt
Total				$ 436,000,000
Discount to par (as a percent)				99.985%	99.985%
Interest rate (as a percent)				2.60%	2.60%
Face amount of debt instrument				$ 1,500,000,000	$ 1,500,000,000
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
Long-term debt
Total		$ 499,000,000		$ 499,000,000
Discount to par (as a percent)		99.771%		99.771%	99.771%
Interest rate (as a percent)		4.05%		4.05%	4.05%
Face amount of debt instrument		$ 500,000,000		$ 500,000,000	$ 500,000,000
2012 Shelf Registration Statement-$750 issued at par in January 2014 at three-month USD LIBOR plus 0.94%, due January 2019
Long-term debt
Total		102,000,000		102,000,000
Face amount of debt instrument	$ 750,000,000	$ 750,000,000		$ 750,000,000
Spread on reference interest rate (as a percent)	0.94%	0.94%		0.94%
2012 Shelf Registration Statement-$1,250 issued at discount to par at a price of 99.954% in January 2014 at 2.75%, due January 2019
Long-term debt
Total		$ 300,000,000		$ 300,000,000
Discount to par (as a percent)	99.954%	99.954%		99.954%
Interest rate (as a percent)	2.75%	2.75%		2.75%
Face amount of debt instrument	$ 1,250,000,000	$ 1,250,000,000		$ 1,250,000,000
Other, including capital lease obligations, at 0.51%-8.30%, due in calendar years 2016-2024
Long-term debt
Other, including capital lease obligations		$ 132,000,000		$ 96,000,000
Minimum interest rate (as a percent)		0.51%
Maximum interest rate (as a percent)		8.30%