Financial Instruments by Balance Sheet Grouping (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Taxes and other current assets	$ 367	[1]	$ 296	[1]
Taxes and other noncurrent assets	961	[2]	1,086	[2]
Other current liabilities	247	[3]	330	[3]
Other noncurrent liabilities	701	[4]	374	[4]
Foreign currency forward-exchange contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Taxes and other current assets	249		152
Other current liabilities	99		243
Foreign Exchange Contract [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Taxes and other current assets	54		144
Taxes and other noncurrent assets	234		50
Other current liabilities	148		87
Other noncurrent liabilities	675		341
Interest rate swaps [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Taxes and other current assets	64
Taxes and other noncurrent assets	727		1,000
Other noncurrent liabilities	$ 26		$ 33

[1] As of March 31, 2013, derivative instruments at fair value include foreign currency forward-exchange contracts ($249 million), interest rate swaps ($64 million), and foreign currency swaps ($54 million) and, as of December 31, 2012, include foreign currency forward-exchange contracts ($152 million) and foreign currency swaps ($144 million).

[2] As of March 31, 2013, derivative instruments at fair value include interest rate swaps ($727 million) and foreign currency swaps ($234 million) and, as of December 31, 2012, include interest rate swaps ($1 billion) and foreign currency swaps ($50 million).

[3] At March 31, 2013, derivative instruments at fair value include foreign currency swaps ($148 million) and foreign currency forward-exchange contracts ($99 million) and, as of December 31, 2012, include foreign currency forward-exchange contracts ($243 million) and foreign currency swaps ($87 million).

[4] At March 31, 2013, derivative instruments at fair value include foreign currency swaps ($675 million) and interest rate swaps ($26 million) and, as of December 31, 2012, include foreign currency swaps ($341 million) and interest rate swaps ($33 million).