Fair Value Measurements and Derivatives - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	$ 144	$ 110
Fair Value, Measurements, Recurring | Other Current Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes receivable		75
Marketable securities	144	110
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring | Other Current Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes receivable		0
Marketable securities	51	33
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Other Current Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes receivable		75
Marketable securities	93	77
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Other Current Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes receivable		0
Marketable securities	0
Foreign Exchange Forward [Member] | Fair Value, Measurements, Recurring | Other Current Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Currency contracts asset value	2	3
Foreign Exchange Forward [Member] | Fair Value, Measurements, Recurring | Current Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Currency contracts liability value	1	2
Foreign Exchange Forward [Member] | Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Other Current Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Currency contracts asset value	2	3
Foreign Exchange Forward [Member] | Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Current Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Currency contracts liability value	1	2
Currency Swap [Member] | Fair Value, Measurements, Recurring | Noncurrent Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Currency contracts asset value		2
Currency Swap [Member] | Fair Value, Measurements, Recurring | Other Noncurrent Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Currency contracts liability value		2
Currency Swap [Member] | Fair Value, Measurements, Recurring | Other Current Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Currency contracts asset value	4
Currency Swap [Member] | Fair Value, Measurements, Recurring | Current Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Currency contracts liability value	5
Currency Swap [Member] | Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Noncurrent Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Currency contracts asset value		2
Currency Swap [Member] | Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Other Noncurrent Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Currency contracts liability value		2
Currency Swap [Member] | Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Other Current Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Currency contracts asset value	4
Currency Swap [Member] | Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Current Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Currency contracts liability value	$ 5