The amount of debt discount that was originally recognized at the issuance of the instrument that has yet to be amortized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number APB14-1

-Paragraph 31

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 21

-Paragraph 16, 20

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 1A

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28541-108399

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 55

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=6584090&loc=d3e28878-108400

Name:	us-gaap_DebtInstrumentUnamortizedDiscount
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Summary of Notes Payable (Parenthetical) (Detail) In Millions, unless otherwise specified	Sep. 30, 2011 8.50% senior notes due May 2019	Dec. 31, 2010 8.50% senior notes due May 2019	Sep. 30, 2011 6.45% senior notes due August 2040 USD ($)	Dec. 31, 2010 6.45% senior notes due August 2040 USD ($)	Sep. 30, 2011 6.90% senior notes due December 2039 USD ($)	Dec. 31, 2010 6.90% senior notes due December 2039 USD ($)	Sep. 30, 2011 3.45% senior notes due August 2015	Dec. 31, 2010 3.45% senior notes due August 2015	Dec. 31, 2010 1.52% yen-denominated Uridashi notes paid September 2011 JPY (¥)	Sep. 30, 2011 2.26% yen-denominated Uridashi notes due September 2016 JPY (¥)	Dec. 31, 2010 2.26% yen-denominated Uridashi notes due September 2016 JPY (¥)	Dec. 31, 2010 Variable interest rate yen-denominated Uridashi notes paid September 2011 JPY (¥)	Sep. 30, 2011 1.47% yen-denominated Samurai notes due July 2014 JPY (¥)	Jul. 31, 2011 1.47% yen-denominated Samurai notes due July 2014 JPY (¥)	Sep. 30, 2011 1.87% yen-denominated Samurai notes due June 2012 JPY (¥)	Dec. 31, 2010 1.87% yen-denominated Samurai notes due June 2012 JPY (¥)	Sep. 30, 2011 1.84% yen-denominated Samurai notes due July 2016 JPY (¥)	Jul. 31, 2011 1.84% yen-denominated Samurai notes due July 2016 JPY (¥)	Sep. 30, 2011 Variable interest rate yen-denominated Samurai notes due July 2014 JPY (¥)	Jul. 31, 2011 Variable interest rate yen-denominated Samurai notes due July 2014 JPY (¥)	Sep. 30, 2011 3.60% yen-denominated loan due July 2015 JPY (¥)	Dec. 31, 2010 3.60% yen-denominated loan due July 2015 JPY (¥)	Sep. 30, 2011 3.00% yen-denominated loan due August 2015 JPY (¥)	Dec. 31, 2010 3.00% yen-denominated loan due August 2015 JPY (¥)
Debt Instrument [Line Items]
Notes payable, interest rate	8.50%	8.50%	6.45%	6.45%	6.90%	6.90%	3.45%	3.45%	1.52%	2.26%	2.26%	0.66%	1.47%	1.47%	1.87%	1.87%	1.84%	1.84%	1.35%		3.60%	3.60%	3.00%	3.00%
Notes payable, principal amount			$ 450	$ 450	$ 400	$ 400			¥ 15,000	¥ 8,000	¥ 8,000	¥ 20,000	¥ 28,700	¥ 28,700	¥ 26,600	¥ 26,600	¥ 15,800	¥ 15,800	¥ 5,500	¥ 5,500	¥ 10,000	¥ 10,000	¥ 5,000	¥ 5,000
Notes payable, underwriting discount			$ 2	$ 2	$ 4	$ 4