Fair Value Measurements ( Fair Value, Measurement Inputs, Disclosure) (Details) (USD $) In Millions	Jun. 30, 2011		Dec. 31, 2010
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term investments	$ 1,748		$ 1,752
Current Assets [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivatives, assets	22	[1]	5	[1]
Current Assets [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivatives, assets	22	[1]	5	[1]
Non-Current Assets [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivatives, assets	41		45
Non-Current Assets [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivatives, assets	41		45
Current Liabilities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivatives, liabilities	87	[1]	155	[1]
Current Liabilities [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivatives, liabilities	87	[1]	155	[1]
Non-Current Liabilities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivatives, liabilities	24	[1]	45	[1]
Non-Current Liabilities [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivatives, liabilities	24	[1]	45	[1]
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term investments	11	[2]	15	[2]
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term investments	$ 1,737		$ 1,737

[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.