Fair Value Measurements and Derivatives - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Marketable securities	$ 165	$ 169
Fair Value, Measurements, Recurring [Member] | Other Current Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Marketable securities	165	169
Fair Value, Measurements, Recurring [Member] | Other Current Assets [Member] | Foreign Exchange Forward [Member] | Not Designated as Hedging Instrument [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Currency contracts asset value	4	1
Fair Value, Measurements, Recurring [Member] | Other Current Assets [Member] | Foreign Exchange Forward [Member] | Cash Flow Hedging [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Currency contracts asset value	1	1
Fair Value, Measurements, Recurring [Member] | Other Current Assets [Member] | Foreign Exchange Forward [Member] | Net Investment Hedging [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Currency contracts asset value	2
Fair Value, Measurements, Recurring [Member] | Other Current Assets [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Marketable securities	65	72
Fair Value, Measurements, Recurring [Member] | Other Current Assets [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Marketable securities	100	97
Fair Value, Measurements, Recurring [Member] | Other Current Assets [Member] | Fair Value, Inputs, Level 2 [Member] | Foreign Exchange Forward [Member] | Not Designated as Hedging Instrument [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Currency contracts asset value	4	1
Fair Value, Measurements, Recurring [Member] | Other Current Assets [Member] | Fair Value, Inputs, Level 2 [Member] | Foreign Exchange Forward [Member] | Cash Flow Hedging [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Currency contracts asset value	1	1
Fair Value, Measurements, Recurring [Member] | Other Current Assets [Member] | Fair Value, Inputs, Level 2 [Member] | Foreign Exchange Forward [Member] | Net Investment Hedging [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Currency contracts asset value	2
Fair Value, Measurements, Recurring [Member] | Current Liabilities [Member] | Foreign Exchange Forward [Member] | Not Designated as Hedging Instrument [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Currency contracts liability value	1
Fair Value, Measurements, Recurring [Member] | Current Liabilities [Member] | Foreign Exchange Forward [Member] | Cash Flow Hedging [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Currency contracts liability value	12	11
Fair Value, Measurements, Recurring [Member] | Current Liabilities [Member] | Currency Swap [Member] | Not Designated as Hedging Instrument [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Currency contracts liability value		9
Fair Value, Measurements, Recurring [Member] | Current Liabilities [Member] | Fair Value, Inputs, Level 2 [Member] | Foreign Exchange Forward [Member] | Not Designated as Hedging Instrument [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Currency contracts liability value	1
Fair Value, Measurements, Recurring [Member] | Current Liabilities [Member] | Fair Value, Inputs, Level 2 [Member] | Foreign Exchange Forward [Member] | Cash Flow Hedging [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Currency contracts liability value	12	11
Fair Value, Measurements, Recurring [Member] | Current Liabilities [Member] | Fair Value, Inputs, Level 2 [Member] | Currency Swap [Member] | Not Designated as Hedging Instrument [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Currency contracts liability value		$ 9