Financial Instruments by Balance Sheet Grouping (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Taxes and other current assets	$ 210	[1]	$ 357	[1]
Taxes and other noncurrent assets	1,073	[2]	1,042	[2]
Other current liabilities	395	[3]	459	[3]
Other noncurrent liabilities	971	[4]	1,306	[4]
Foreign currency forward-exchange contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Taxes and other current assets	178		349
Other current liabilities	165		355
Foreign Exchange Contract [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Taxes and other current assets	20
Taxes and other noncurrent assets	56		17
Other current liabilities	230		104
Other noncurrent liabilities	942		1,300
Interest rate swaps [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Taxes and other current assets	12		8
Taxes and other noncurrent assets	1,000		1,000
Other noncurrent liabilities	$ 29		$ 14

[1] As of September 30, 2012, derivative instruments at fair value include foreign currency forward-exchange contracts ($178 million), foreign currency swaps ($20 million) and interest rate swaps ($12 million) and, as of December 31, 2011, include foreign currency forward-exchange contracts ($349 million) and interest rate swaps ($8 million).

[2] As of September 30, 2012, derivative instruments at fair value include interest rate swaps ($1.0 billion) and foreign currency swaps ($56 million) and, as of December 31, 2011, include interest rate swaps ($1 billion) and foreign currency swaps ($17 million).

[3] At September 30, 2012, derivative instruments at fair value include foreign currency swaps ($230 million) and foreign currency forward-exchange contracts ($165 million) and, as of December 31, 2011, include foreign currency forward-exchange contracts ($355 million) and foreign currency swaps ($104 million).

[4] At September 30, 2012, derivative instruments at fair value include foreign currency swaps ($942 million) and interest rate swaps ($29 million) and, as of December 31, 2011, include foreign currency swaps ($1.3 billion) and interest rate swaps ($14 million).