Fair Value Measurements - Input Hierarchy of Items Measured at Fair Value on a Recurring Basis (Details) (USD $) | Jun. 30, 2014 | Dec. 31, 2013 |
Derivative Financial Instrument Assets | ' | ' |
Derivative financial instruments assets | $1,000,000,000 | ' |
Automotive [Member] | ' | ' |
Derivative Financial Instrument Assets | ' | ' |
Derivative financial instruments assets | 325,000,000 | 580,000,000 |
Derivative financial instruments liabilities | ' | ' |
Derivative financial instruments liabilities | 474,000,000 | 418,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 0 | 233,000,000 |
Marketable securities | ' | ' |
Marketable securities | 21,076,000,000 | 20,157,000,000 |
Derivative Financial Instrument Assets | ' | ' |
Derivative financial instruments assets | 325,000,000 | 580,000,000 |
Total assets at fair value | 21,401,000,000 | 20,970,000,000 |
Derivative financial instruments liabilities | ' | ' |
Derivative financial instruments liabilities | 474,000,000 | 418,000,000 |
Total liabilities at fair value | 474,000,000 | 418,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | US Treasury and Government [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 0 | 33,000,000 |
Marketable securities | ' | ' |
Marketable securities | 8,027,000,000 | 10,348,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Foreign Government and Agencies [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 0 | 200,000,000 |
Marketable securities | ' | ' |
Marketable securities | 9,689,000,000 | 6,538,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 2,690,000,000 | 2,623,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Equities [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 310,000,000 | 341,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Other marketable securities [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 360,000,000 | 307,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Cash equivalents - financial instruments [Member] | ' | ' |
Input Hierarchy of Items Measured at Fair Value on a Recurring Basis - Footnote Narrative | ' | ' |
Par Value Assets Excluded From Fair Value By Input | 3,100,000,000 | 2,700,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Cash [Member] | ' | ' |
Input Hierarchy of Items Measured at Fair Value on a Recurring Basis - Footnote Narrative | ' | ' |
Par Value Assets Excluded From Fair Value By Input | 1,600,000,000 | 2,000,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 0 | 0 |
Marketable securities | ' | ' |
Marketable securities | 2,522,000,000 | 4,093,000,000 |
Derivative Financial Instrument Assets | ' | ' |
Derivative financial instruments assets | 0 | 0 |
Total assets at fair value | 2,522,000,000 | 4,093,000,000 |
Derivative financial instruments liabilities | ' | ' |
Derivative financial instruments liabilities | 0 | 0 |
Total liabilities at fair value | 0 | 0 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | US Treasury and Government [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 0 | 0 |
Marketable securities | ' | ' |
Marketable securities | 2,212,000,000 | 3,752,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Foreign Government and Agencies [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 0 | 0 |
Marketable securities | ' | ' |
Marketable securities | 0 | 0 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Corporate Debt [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 0 | 0 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Equities [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 310,000,000 | 341,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Other marketable securities [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 0 | 0 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 0 | 233,000,000 |
Marketable securities | ' | ' |
Marketable securities | 18,554,000,000 | 16,064,000,000 |
Derivative Financial Instrument Assets | ' | ' |
Derivative financial instruments assets | 322,000,000 | 579,000,000 |
Total assets at fair value | 18,876,000,000 | 16,876,000,000 |
Derivative financial instruments liabilities | ' | ' |
Derivative financial instruments liabilities | 474,000,000 | 416,000,000 |
Total liabilities at fair value | 474,000,000 | 416,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | US Treasury and Government [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 0 | 33,000,000 |
Marketable securities | ' | ' |
Marketable securities | 5,815,000,000 | 6,596,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Foreign Government and Agencies [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 0 | 200,000,000 |
Marketable securities | ' | ' |
Marketable securities | 9,689,000,000 | 6,538,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Corporate Debt [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 2,690,000,000 | 2,623,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Equities [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 0 | 0 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Other marketable securities [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 360,000,000 | 307,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 0 | 0 |
Marketable securities | ' | ' |
Marketable securities | 0 | 0 |
Derivative Financial Instrument Assets | ' | ' |
Derivative financial instruments assets | 3,000,000 | 1,000,000 |
Total assets at fair value | 3,000,000 | 1,000,000 |
Derivative financial instruments liabilities | ' | ' |
Derivative financial instruments liabilities | 0 | 2,000,000 |
Total liabilities at fair value | 0 | 2,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | US Treasury and Government [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 0 | 0 |
Marketable securities | ' | ' |
Marketable securities | 0 | 0 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Foreign Government and Agencies [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 0 | 0 |
Marketable securities | ' | ' |
Marketable securities | 0 | 0 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Corporate Debt [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 0 | 0 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Equities [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 0 | 0 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Other marketable securities [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 0 | 0 |
Financial Services [Member] | ' | ' |
Derivative Financial Instrument Assets | ' | ' |
Derivative financial instruments assets | 673,000,000 | 585,000,000 |
Derivative financial instruments liabilities | ' | ' |
Derivative financial instruments liabilities | 320,000,000 | 506,000,000 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 365,000,000 | 24,000,000 |
Marketable securities | ' | ' |
Marketable securities | 3,020,000,000 | 1,943,000,000 |
Derivative Financial Instrument Assets | ' | ' |
Derivative financial instruments assets | 673,000,000 | 585,000,000 |
Total assets at fair value | 4,058,000,000 | 2,552,000,000 |
Derivative financial instruments liabilities | ' | ' |
Derivative financial instruments liabilities | 320,000,000 | 506,000,000 |
Total liabilities at fair value | 320,000,000 | 506,000,000 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | US Treasury and Government [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 0 | 0 |
Marketable securities | ' | ' |
Marketable securities | 905,000,000 | 443,000,000 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Foreign Government and Agencies [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 365,000,000 | 24,000,000 |
Marketable securities | ' | ' |
Marketable securities | 519,000,000 | 184,000,000 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 1,558,000,000 | 1,273,000,000 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Other marketable securities [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 38,000,000 | 43,000,000 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Cash equivalents - financial instruments [Member] | ' | ' |
Input Hierarchy of Items Measured at Fair Value on a Recurring Basis - Footnote Narrative | ' | ' |
Par Value Assets Excluded From Fair Value By Input | 4,500,000,000 | 6,700,000,000 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Cash [Member] | ' | ' |
Input Hierarchy of Items Measured at Fair Value on a Recurring Basis - Footnote Narrative | ' | ' |
Par Value Assets Excluded From Fair Value By Input | 1,900,000,000 | 2,800,000,000 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 0 | 0 |
Marketable securities | ' | ' |
Marketable securities | 43,000,000 | 418,000,000 |
Derivative Financial Instrument Assets | ' | ' |
Derivative financial instruments assets | 0 | 0 |
Total assets at fair value | 43,000,000 | 418,000,000 |
Derivative financial instruments liabilities | ' | ' |
Derivative financial instruments liabilities | 0 | 0 |
Total liabilities at fair value | 0 | 0 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | US Treasury and Government [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 0 | 0 |
Marketable securities | ' | ' |
Marketable securities | 43,000,000 | 418,000,000 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Foreign Government and Agencies [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 0 | 0 |
Marketable securities | ' | ' |
Marketable securities | 0 | 0 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Corporate Debt [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 0 | 0 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Other marketable securities [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 0 | 0 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 365,000,000 | 24,000,000 |
Marketable securities | ' | ' |
Marketable securities | 2,977,000,000 | 1,525,000,000 |
Derivative Financial Instrument Assets | ' | ' |
Derivative financial instruments assets | 673,000,000 | 585,000,000 |
Total assets at fair value | 4,015,000,000 | 2,134,000,000 |
Derivative financial instruments liabilities | ' | ' |
Derivative financial instruments liabilities | 320,000,000 | 506,000,000 |
Total liabilities at fair value | 320,000,000 | 506,000,000 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | US Treasury and Government [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 0 | 0 |
Marketable securities | ' | ' |
Marketable securities | 862,000,000 | 25,000,000 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Foreign Government and Agencies [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 365,000,000 | 24,000,000 |
Marketable securities | ' | ' |
Marketable securities | 519,000,000 | 184,000,000 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Corporate Debt [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 1,558,000,000 | 1,273,000,000 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Other marketable securities [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 38,000,000 | 43,000,000 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 0 | 0 |
Marketable securities | ' | ' |
Marketable securities | 0 | 0 |
Derivative Financial Instrument Assets | ' | ' |
Derivative financial instruments assets | 0 | 0 |
Total assets at fair value | 0 | 0 |
Derivative financial instruments liabilities | ' | ' |
Derivative financial instruments liabilities | 0 | 0 |
Total liabilities at fair value | 0 | 0 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | US Treasury and Government [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 0 | 0 |
Marketable securities | ' | ' |
Marketable securities | 0 | 0 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Foreign Government and Agencies [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 0 | 0 |
Marketable securities | ' | ' |
Marketable securities | 0 | 0 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Corporate Debt [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 0 | 0 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Other marketable securities [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | $0 | $0 |