Financial Instruments (Fair Values Of Derivatives Instruments) (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Schedule of Cost-method Investments [Line Items]
Fair Value, Asset Derivatives	$ 5	$ 28
Fair Value, Liability Derivatives	23	9
Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member]
Schedule of Cost-method Investments [Line Items]
Fair Value, Asset Derivatives	0	0
Fair Value, Liability Derivatives	2	3
Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member]
Schedule of Cost-method Investments [Line Items]
Fair Value, Liability Derivatives	12
Not Designated As Hedging Instruments [Member] | Foreign Exchange Contracts [Member]
Schedule of Cost-method Investments [Line Items]
Fair Value, Asset Derivatives	3	26
Fair Value, Liability Derivatives	8	1
Not Designated As Hedging Instruments [Member] | Interest Rate Contracts [Member]
Schedule of Cost-method Investments [Line Items]
Fair Value, Asset Derivatives	1	2
Fair Value, Liability Derivatives	1	4
Not Designated As Hedging Instruments [Member] | Commodity Contracts [Member]
Schedule of Cost-method Investments [Line Items]
Fair Value, Asset Derivatives	1
Fair Value, Liability Derivatives		$ 1