Fair Value Measurements (Schedule Of Major Categories Of Financial Assets And Liabilities Measured On A Recurring Basis) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	$ 273		$ 196
Current Assets [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term investments	1,399		1,164
Other current assets	24	[1]	12	[1]
Current Assets [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term investments	1,399		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	24	[1]	12	[1]
Asset-Backed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other current assets	40
Asset-Backed Securities [Member] | Non-Current Assets [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets			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			35	[3]
Asset-Backed Securities And Derivative Assets [Member] | Non-Current Assets [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	41	[1],[4]
Asset-Backed Securities And Derivative Assets [Member] | Non-Current Assets [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	41	[1],[4]
Other Accrued Liabilities [Member] | Current Liabilities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivatives, liabilities	36	[1]	163	[1]
Other Accrued Liabilities [Member] | Current Liabilities [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivatives, liabilities	36	[1]	163	[1]
Other Liabilities [Member] | Non-Current Liabilities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivatives, liabilities	5	[1]	6	[1]
Other Liabilities [Member] | Non-Current Liabilities [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivatives, liabilities	$ 5	[1]	$ 6	[1]

[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.

[4] Other assets include $40 million of asset-backed securities which are measured using observable quoted prices for similar assets.