Fair Value Measurements (Details) (USD $)
In Millions, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities $ 1,031 $ 1,454
Gross Amounts of Derivative Assets Presented in the Consolidated Balance Sheet 561 256
Gross Amounts of Derivative Liabilities Presented in the Consolidated Balance Sheet 73 43
Fair value on a recurring basis | Fair Value | Foreign currency forward/option contracts    
Assets and Liabilities Measured on Recurring Basis    
Gross Amounts of Derivative Assets Presented in the Consolidated Balance Sheet 529 229
Gross Amounts of Derivative Liabilities Presented in the Consolidated Balance Sheet 69 36
Fair value on a recurring basis | Fair Value | Commodity price swap contracts    
Assets and Liabilities Measured on Recurring Basis    
Gross Amounts of Derivative Assets Presented in the Consolidated Balance Sheet 1  
Gross Amounts of Derivative Liabilities Presented in the Consolidated Balance Sheet 4 4
Fair value on a recurring basis | Fair Value | Interest rate swap contracts    
Assets and Liabilities Measured on Recurring Basis    
Gross Amounts of Derivative Assets Presented in the Consolidated Balance Sheet 31 27
Gross Amounts of Derivative Liabilities Presented in the Consolidated Balance Sheet   3
Fair value on a recurring basis | Fair Value | U.S. government agency securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 68 108
Fair value on a recurring basis | Fair Value | Foreign government agency securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 60 95
Fair value on a recurring basis | Fair Value | Corporate debt securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 551 619
Fair value on a recurring basis | Fair Value | Certificates of deposit/time deposits    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 24 41
Fair value on a recurring basis | Fair Value | Commercial paper    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 27  
Fair value on a recurring basis | Fair Value | Asset-backed securities Automobile loan related    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 167 282
Fair value on a recurring basis | Fair Value | Asset-backed securities Credit card related    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 66 162
Fair value on a recurring basis | Fair Value | Asset-backed securities Equipment lease related    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 7 48
Fair value on a recurring basis | Fair Value | Asset-backed securities Other asset-backed securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 46 46
Fair value on a recurring basis | Fair Value | U.S. treasury securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities   38
Fair value on a recurring basis | Fair Value | U.S. municipal securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 15 15
Fair value on a recurring basis | Fair Value | Investments    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 1 1
Fair value on a recurring basis | Level 1 | Foreign currency forward/option contracts    
Assets and Liabilities Measured on Recurring Basis    
Gross Amounts of Derivative Assets Presented in the Consolidated Balance Sheet 0 0
Gross Amounts of Derivative Liabilities Presented in the Consolidated Balance Sheet 0 0
Fair value on a recurring basis | Level 1 | Commodity price swap contracts    
Assets and Liabilities Measured on Recurring Basis    
Gross Amounts of Derivative Assets Presented in the Consolidated Balance Sheet 0  
Gross Amounts of Derivative Liabilities Presented in the Consolidated Balance Sheet 0 0
Fair value on a recurring basis | Level 1 | Interest rate swap contracts    
Assets and Liabilities Measured on Recurring Basis    
Gross Amounts of Derivative Assets Presented in the Consolidated Balance Sheet 0 0
Gross Amounts of Derivative Liabilities Presented in the Consolidated Balance Sheet   0
Fair value on a recurring basis | Level 1 | U.S. government agency securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 0 0
Fair value on a recurring basis | Level 1 | Foreign government agency securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 0 0
Fair value on a recurring basis | Level 1 | Corporate debt securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 0 0
Fair value on a recurring basis | Level 1 | Certificates of deposit/time deposits    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 0 0
Fair value on a recurring basis | Level 1 | Commercial paper    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 0  
Fair value on a recurring basis | Level 1 | Asset-backed securities Automobile loan related    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 0 0
Fair value on a recurring basis | Level 1 | Asset-backed securities Credit card related    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 0 0
Fair value on a recurring basis | Level 1 | Asset-backed securities Equipment lease related    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 0 0
Fair value on a recurring basis | Level 1 | Asset-backed securities Other asset-backed securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 0 0
Fair value on a recurring basis | Level 1 | U.S. treasury securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities   38
Fair value on a recurring basis | Level 1 | U.S. municipal securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 0 0
Fair value on a recurring basis | Level 1 | Investments    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 1 1
Fair value on a recurring basis | Level 2 | Foreign currency forward/option contracts    
Assets and Liabilities Measured on Recurring Basis    
Gross Amounts of Derivative Assets Presented in the Consolidated Balance Sheet 529 229
Gross Amounts of Derivative Liabilities Presented in the Consolidated Balance Sheet 69 36
Fair value on a recurring basis | Level 2 | Commodity price swap contracts    
Assets and Liabilities Measured on Recurring Basis    
Gross Amounts of Derivative Assets Presented in the Consolidated Balance Sheet 1  
Gross Amounts of Derivative Liabilities Presented in the Consolidated Balance Sheet 4 4
Fair value on a recurring basis | Level 2 | Interest rate swap contracts    
Assets and Liabilities Measured on Recurring Basis    
Gross Amounts of Derivative Assets Presented in the Consolidated Balance Sheet 31 27
Gross Amounts of Derivative Liabilities Presented in the Consolidated Balance Sheet   3
Fair value on a recurring basis | Level 2 | U.S. government agency securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 68 108
Fair value on a recurring basis | Level 2 | Foreign government agency securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 60 95
Fair value on a recurring basis | Level 2 | Corporate debt securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 551 619
Fair value on a recurring basis | Level 2 | Certificates of deposit/time deposits    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 24 41
Fair value on a recurring basis | Level 2 | Commercial paper    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 27  
Fair value on a recurring basis | Level 2 | Asset-backed securities Automobile loan related    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 167 282
Fair value on a recurring basis | Level 2 | Asset-backed securities Credit card related    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 66 162
Fair value on a recurring basis | Level 2 | Asset-backed securities Equipment lease related    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 7 48
Fair value on a recurring basis | Level 2 | Asset-backed securities Other asset-backed securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 46 46
Fair value on a recurring basis | Level 2 | U.S. treasury securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities   0
Fair value on a recurring basis | Level 2 | U.S. municipal securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 0 0
Fair value on a recurring basis | Level 2 | Investments    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 0 0
Fair value on a recurring basis | Level 3 | Foreign currency forward/option contracts    
Assets and Liabilities Measured on Recurring Basis    
Gross Amounts of Derivative Assets Presented in the Consolidated Balance Sheet 0 0
Gross Amounts of Derivative Liabilities Presented in the Consolidated Balance Sheet 0 0
Fair value on a recurring basis | Level 3 | Commodity price swap contracts    
Assets and Liabilities Measured on Recurring Basis    
Gross Amounts of Derivative Assets Presented in the Consolidated Balance Sheet 0  
Gross Amounts of Derivative Liabilities Presented in the Consolidated Balance Sheet 0 0
Fair value on a recurring basis | Level 3 | Interest rate swap contracts    
Assets and Liabilities Measured on Recurring Basis    
Gross Amounts of Derivative Assets Presented in the Consolidated Balance Sheet 0 0
Gross Amounts of Derivative Liabilities Presented in the Consolidated Balance Sheet   0
Fair value on a recurring basis | Level 3 | U.S. government agency securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 0 0
Fair value on a recurring basis | Level 3 | Foreign government agency securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 0 0
Fair value on a recurring basis | Level 3 | Corporate debt securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 0 0
Fair value on a recurring basis | Level 3 | Certificates of deposit/time deposits    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 0 0
Fair value on a recurring basis | Level 3 | Commercial paper    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 0  
Fair value on a recurring basis | Level 3 | Asset-backed securities Automobile loan related    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 0 0
Fair value on a recurring basis | Level 3 | Asset-backed securities Credit card related    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 0 0
Fair value on a recurring basis | Level 3 | Asset-backed securities Equipment lease related    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 0 0
Fair value on a recurring basis | Level 3 | Asset-backed securities Other asset-backed securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 0 0
Fair value on a recurring basis | Level 3 | U.S. treasury securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities   0
Fair value on a recurring basis | Level 3 | U.S. municipal securities    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities 15 15
Fair value on a recurring basis | Level 3 | Investments    
Assets and Liabilities Measured on Recurring Basis    
Available-for-sale marketable securities $ 0 $ 0