Fair Value Measurements (Schedule Of Major Categories Of Financial Assets And Liabilities Measured On A Recurring Basis) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012		Dec. 31, 2011
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	$ 259		$ 196
Current Assets [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term investments	1,346		1,164
Other current assets	101	[1]	12	[1]
Current Assets [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term investments	1,346		1,155
Current Assets [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term investments			9	[2]
Other current assets	101	[1]	12	[1]
Current Liabilities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivatives, liabilities	15	[1]	163	[1]
Current Liabilities [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivatives, liabilities	15	[1]	163	[1]
Non-Current Liabilities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivatives, liabilities	3	[1]	6	[1]
Non-Current Liabilities [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivatives, liabilities	3	[1]	6	[1]
Asset-Backed Securities [Member] | Non-Current Assets [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	36	[3]	35	[3]
Asset-Backed Securities [Member] | Non-Current Assets [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	$ 36	[3]	$ 35	[3]

[1] Derivative assets and liabilities include foreign exchange contracts which are measured using observable quoted prices for similar assets and liabilities

[2] Short-term investments are measured using observable quoted prices for similar assets

[3] Other assets include asset backed securities which are measured using observable quoted prices for similar assets