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