Debt (Narrative) (Details)	0 Months Ended		3 Months Ended			0 Months Ended			0 Months Ended			0 Months Ended			0 Months Ended			0 Months Ended	3 Months Ended		0 Months Ended			1 Months Ended							3 Months Ended		1 Months Ended
	Dec. 01, 2010 USD ($) Y	Mar. 10, 2010 USD ($) Y	Mar. 31, 2012 USD ($) D	Dec. 31, 2011 USD ($)	Nov. 08, 2010 USD ($)	Mar. 10, 2010 Senior Notes Due 2013 [Member] USD ($) Y	Mar. 31, 2012 Senior Notes Due 2013 [Member] USD ($)	Dec. 31, 2011 Senior Notes Due 2013 [Member] USD ($)	Jul. 28, 2009 Senior Notes Due 2014 [Member] USD ($) Y	Mar. 31, 2012 Senior Notes Due 2014 [Member] USD ($)	Dec. 31, 2011 Senior Notes Due 2014 [Member] USD ($)	Dec. 01, 2010 Senior Notes Due 2016 [Member] USD ($) Y	Mar. 31, 2012 Senior Notes Due 2016 [Member] USD ($)	Dec. 31, 2011 Senior Notes Due 2016 [Member] USD ($)	Jul. 28, 2009 Senior Notes Due 2019 [Member] USD ($) Y	Mar. 31, 2012 Senior Notes Due 2019 [Member] USD ($)	Dec. 31, 2011 Senior Notes Due 2019 [Member] USD ($)	Apr. 28, 2010 Yen-Denominated Senior Note 1.58% [Member] JPY (¥) Y	Mar. 31, 2012 Yen-Denominated Senior Note 1.58% [Member] USD ($)	Dec. 31, 2011 Yen-Denominated Senior Note 1.58% [Member] USD ($)	Apr. 28, 2010 Yen-Denominated Senior Note 2.04% [Member] JPY (¥) Y	Mar. 31, 2012 Yen-Denominated Senior Note 2.04% [Member] USD ($)	Dec. 31, 2011 Yen-Denominated Senior Note 2.04% [Member] USD ($)	Mar. 31, 2011 Yen Denominated Credit Facilities Due 2013 [Member]	Mar. 31, 2011 Yen-Denominated Credit Facility Due 2012 [Member]	Mar. 31, 2012 Yen-Denominated Credit Facility Due 2012 [Member] USD ($)	Dec. 31, 2011 Yen-Denominated Credit Facility Due 2012 [Member] USD ($)	Mar. 31, 2012 Yen-Denominated Credit Facilities [Member] USD ($)	Dec. 31, 2011 Yen-Denominated Credit Facilities [Member] USD ($)	Mar. 31, 2011 Yen-Denominated Credit Facilities [Member] JPY (¥)	Mar. 31, 2012 Commercial Paper Borrowings [Member] USD ($)	Dec. 31, 2011 Commercial Paper Borrowings [Member] USD ($)	Dec. 31, 2010 Credit Facility [Member] USD ($)	Mar. 31, 2011 Yen-Denominated Credit Facility 1 [Member]	Mar. 31, 2011 Yen-Denominated Credit Facility 2 [Member]
Debt Instrument [Line Items]
Expected minimum principal payments in 2012			$ 39,000,000
Expected minimum principal payments in 2013			489,000,000
Expected minimum principal payments in 2014			700,000,000
Expected minimum principal payments in 2015			483,000,000
Expected minimum principal payments in 2016			500,000,000
Expected minimum principal payments in 2017			98,000,000
Expected minimum principal payments thereafter			654,000,000
Issued principal amount						450,000,000			700,000,000			500,000,000			500,000,000			8,100,000,000	98,000,000	104,000,000	12,800,000,000	154,000,000	164,000,000
Debt instrument, due date						September 2013			July 2014			January 2016			July 2019				April 28, 2017		April 28, 2020			March 2013	June 2012
Debt instrument term, years						3			5			5			10			7			10
Debt instrument, stated percentage rate						2.20%	2.20%		3.75%	3.75%		2.50%	2.50%		4.875%	4.875%		1.58%	1.58%		2.04%	2.04%
Debt instrument, effective interest rate						2.23%			3.78%			2.54%			5.04%
Interest rate swap term, years	5	3
Notional amount interest rate swap designated as a fair value hedge	500,000,000	450,000,000
Proceeds from termination of interest rate swap					19,000,000
Net average interest rate		0.80%
Outstanding balance under yen denominated credit facilities																												78,000,000	83,000,000	6,500,000,000
Maximum borrowing capacity																														11,250,000,000
Debt instrument basis spread																																	0.875%	0.275%	0.25%
long term debt, commercial paper			2,986,000,000	2,796,000,000			459,000,000	461,000,000		700,000,000	699,000,000		519,000,000	518,000,000		495,000,000	495,000,000		98,000,000	104,000,000		154,000,000	164,000,000			78,000,000	83,000,000				483,000,000	272,000,000
Unused borrowing capacity																																	1,500,000,000
Maximum days commercial paper program provides for the issuance of short-term, unsecured commercial paper			270
Weighted average effective interest rate																															0.23%
Credit facility expiration date																																	February 2015
Fair value of interest rate swap			$ 19,000,000