Fair Value Measurements - Input Hierarchy of Items Measured at Fair Value on a Recurring Basis (Details) (USD $) | Sep. 30, 2014 | Dec. 31, 2013 |
Automotive [Member] | ' | ' |
Derivative Financial Instrument Assets | ' | ' |
Derivative financial instruments assets | $537,000,000 | $580,000,000 |
Derivative financial instruments liabilities | ' | ' |
Derivative financial instruments liabilities | 699,000,000 | 418,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 98,000,000 | 233,000,000 |
Marketable securities | ' | ' |
Marketable securities | 16,876,000,000 | 20,157,000,000 |
Derivative Financial Instrument Assets | ' | ' |
Derivative financial instruments assets | 537,000,000 | 580,000,000 |
Total assets at fair value | 17,511,000,000 | 20,970,000,000 |
Derivative financial instruments liabilities | ' | ' |
Derivative financial instruments liabilities | 699,000,000 | 418,000,000 |
Total liabilities at fair value | 699,000,000 | 418,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | US Treasury and Government [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 58,000,000 | 33,000,000 |
Marketable securities | ' | ' |
Marketable securities | 6,034,000,000 | 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 | 7,487,000,000 | 6,538,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt [Domain] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 40,000,000 | 0 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 2,685,000,000 | 2,623,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Equities [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 328,000,000 | 341,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Other marketable securities [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 342,000,000 | 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 | 4,700,000,000 | 2,800,000,000 |
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 | 1,200,000,000 | 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 | 1,306,000,000 | 4,093,000,000 |
Derivative Financial Instrument Assets | ' | ' |
Derivative financial instruments assets | 0 | 0 |
Total assets at fair value | 1,306,000,000 | 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 | 978,000,000 | 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 [Domain] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 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 | 328,000,000 | 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 | 98,000,000 | 233,000,000 |
Marketable securities | ' | ' |
Marketable securities | 15,570,000,000 | 16,064,000,000 |
Derivative Financial Instrument Assets | ' | ' |
Derivative financial instruments assets | 535,000,000 | 579,000,000 |
Total assets at fair value | 16,203,000,000 | 16,876,000,000 |
Derivative financial instruments liabilities | ' | ' |
Derivative financial instruments liabilities | 697,000,000 | 416,000,000 |
Total liabilities at fair value | 697,000,000 | 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 | 58,000,000 | 33,000,000 |
Marketable securities | ' | ' |
Marketable securities | 5,056,000,000 | 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 | 7,487,000,000 | 6,538,000,000 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Corporate Debt [Domain] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 40,000,000 | 0 |
Automotive [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Corporate Debt [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 2,685,000,000 | 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 | 342,000,000 | 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 | 2,000,000 | 1,000,000 |
Total assets at fair value | 2,000,000 | 1,000,000 |
Derivative financial instruments liabilities | ' | ' |
Derivative financial instruments liabilities | 2,000,000 | 2,000,000 |
Total liabilities at fair value | 2,000,000 | 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 [Domain] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 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 | 751,000,000 | 585,000,000 |
Derivative financial instruments liabilities | ' | ' |
Derivative financial instruments liabilities | 291,000,000 | 506,000,000 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 441,000,000 | 24,000,000 |
Marketable securities | ' | ' |
Marketable securities | 3,767,000,000 | 1,943,000,000 |
Derivative Financial Instrument Assets | ' | ' |
Derivative financial instruments assets | 751,000,000 | 585,000,000 |
Total assets at fair value | 4,959,000,000 | 2,552,000,000 |
Derivative financial instruments liabilities | ' | ' |
Derivative financial instruments liabilities | 291,000,000 | 506,000,000 |
Total liabilities at fair value | 291,000,000 | 506,000,000 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | US Treasury and Government [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 40,000,000 | 0 |
Marketable securities | ' | ' |
Marketable securities | 1,563,000,000 | 443,000,000 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Foreign Government and Agencies [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 341,000,000 | 24,000,000 |
Marketable securities | ' | ' |
Marketable securities | 644,000,000 | 184,000,000 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt [Domain] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 60,000,000 | 0 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 1,525,000,000 | 1,273,000,000 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Other marketable securities [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 35,000,000 | 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 | 4,200,000,000 | 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 | 2,700,000,000 | 2,800,000,000 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 40,000,000 | 0 |
Marketable securities | ' | ' |
Marketable securities | 341,000,000 | 418,000,000 |
Derivative Financial Instrument Assets | ' | ' |
Derivative financial instruments assets | 0 | 0 |
Total assets at fair value | 381,000,000 | 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 | 40,000,000 | 0 |
Marketable securities | ' | ' |
Marketable securities | 341,000,000 | 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 [Domain] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 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 | 401,000,000 | 24,000,000 |
Marketable securities | ' | ' |
Marketable securities | 3,426,000,000 | 1,525,000,000 |
Derivative Financial Instrument Assets | ' | ' |
Derivative financial instruments assets | 751,000,000 | 585,000,000 |
Total assets at fair value | 4,578,000,000 | 2,134,000,000 |
Derivative financial instruments liabilities | ' | ' |
Derivative financial instruments liabilities | 291,000,000 | 506,000,000 |
Total liabilities at fair value | 291,000,000 | 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 | 1,222,000,000 | 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 | 341,000,000 | 24,000,000 |
Marketable securities | ' | ' |
Marketable securities | 644,000,000 | 184,000,000 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Corporate Debt [Domain] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 60,000,000 | 0 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Corporate Debt [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 1,525,000,000 | 1,273,000,000 |
Financial Services [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Other marketable securities [Member] | ' | ' |
Marketable securities | ' | ' |
Marketable securities | 35,000,000 | 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 [Domain] | ' | ' |
Cash equivalents - financial instruments | ' | ' |
Cash equivalents - financial instruments | 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 |