Fair Value of Pension Plan Assets (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 1,540		$ 1,576
Equity Securities | US All Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	56	[1]	66	[1]
Equity Securities | US Large Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	114		115
Equity Securities | US Small Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	35		35
Equity Securities | Foreign Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	127		160
Equity Securities | Emerging Markets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	52		65
Fixed Income Securities | Emerging Markets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	44		41
Fixed Income Securities | US Corporate Bonds and US Government Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	163	[2]	112	[2]
Fixed Income Securities | Corporate Bond Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	501		467
Fixed Income Securities | US Treasury Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	265		219
Fixed Income Securities | Foreign Government Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	24		91
Alternative Investment | Hedge Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	73	[3]	78	[3]
Alternative Investment | Insurance Contracts
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	10	[4]	10	[4]
Real Estate
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	42		19
Other securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6		5
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	28		93
United States Pension Plans of US Entity, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,497		1,456		1,401
United States Pension Plans of US Entity, Defined Benefit | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	384		441
United States Pension Plans of US Entity, Defined Benefit | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	997		917
United States Pension Plans of US Entity, Defined Benefit | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	116		98
United States Pension Plans of US Entity, Defined Benefit | Equity Securities | Fair Value, Inputs, Level 1 | US All Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	56	[1]	66	[1]
United States Pension Plans of US Entity, Defined Benefit | Equity Securities | Fair Value, Inputs, Level 1 | US Large Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	114		115
United States Pension Plans of US Entity, Defined Benefit | Equity Securities | Fair Value, Inputs, Level 1 | US Small Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	35		35
United States Pension Plans of US Entity, Defined Benefit | Equity Securities | Fair Value, Inputs, Level 1 | Foreign Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	127		160
United States Pension Plans of US Entity, Defined Benefit | Equity Securities | Fair Value, Inputs, Level 1 | Emerging Markets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	52		65
United States Pension Plans of US Entity, Defined Benefit | Fixed Income Securities | Fair Value, Inputs, Level 2 | Emerging Markets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	44		41
United States Pension Plans of US Entity, Defined Benefit | Fixed Income Securities | Fair Value, Inputs, Level 2 | US Corporate Bonds and US Government Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	163	[2]	112	[2]
United States Pension Plans of US Entity, Defined Benefit | Fixed Income Securities | Fair Value, Inputs, Level 2 | Corporate Bond Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	501		463
United States Pension Plans of US Entity, Defined Benefit | Fixed Income Securities | Fair Value, Inputs, Level 2 | US Treasury Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	265		219
United States Pension Plans of US Entity, Defined Benefit | Alternative Investment | Fair Value, Inputs, Level 3 | Hedge Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	73	[3]	78	[3]
United States Pension Plans of US Entity, Defined Benefit | Real Estate | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	42		19
United States Pension Plans of US Entity, Defined Benefit | Other securities | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1		1
United States Pension Plans of US Entity, Defined Benefit | Cash and Cash Equivalents | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	24		82
Foreign Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	43		120		136
Foreign Pension Plans, Defined Benefit | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	33		110
Foreign Pension Plans, Defined Benefit | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	10		10
Foreign Pension Plans, Defined Benefit | Fixed Income Securities | Fair Value, Inputs, Level 2 | Corporate Bond Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			4
Foreign Pension Plans, Defined Benefit | Fixed Income Securities | Fair Value, Inputs, Level 2 | Foreign Government Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	24		91
Foreign Pension Plans, Defined Benefit | Alternative Investment | Fair Value, Inputs, Level 3 | Insurance Contracts
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	10	[4]	10	[4]
Foreign Pension Plans, Defined Benefit | Other securities | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5		4
Foreign Pension Plans, Defined Benefit | Cash and Cash Equivalents | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 4		$ 11

[1] This category comprises a combination of small-, mid- and large-cap equity stocks that are allocated at the investment manager's discretion.

[2] This category represents a combination of investment grade corporate bonds, sovereign bonds, Yankee bonds, asset backed securities and U.S. government bonds.

[3] This category includes fund managers that invest in a well-diversified group of hedge funds where strategies include, but are not limited to, event driven, relative value, long/short market neutral, multistrategy and global macro.

[4] This category comprises contracts placed with insurance companies where the underlying assets are invested in fixed interest securities.