Fair Value Measurements - Summary of Assets Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Millions | Jun. 30, 2018 | Dec. 31, 2017 |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | $ 4,381 | $ 4,771 |
Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 4,381 | |
Restricted cash and short-term investments | 183 | |
Long-term investments | 216 | |
Total | 4,780 | |
Recurring [Member] | Money Market Funds [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 27 | |
Recurring [Member] | Corporate Obligations [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 1,301 | |
Recurring [Member] | Corporate Obligations [Member] | Maturity Dates Exceeding One Year [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 100 | |
Recurring [Member] | Bank Notes / Certificates of Deposit / Time Deposits [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 2,803 | |
Recurring [Member] | Bank Notes / Certificates of Deposit / Time Deposits [Member] | Maturity Dates Exceeding One Year [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 475 | |
Recurring [Member] | Repurchase Agreements [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 250 | |
Recurring [Member] | Level 1 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 27 | |
Restricted cash and short-term investments | 42 | |
Long-term investments | 216 | |
Total | 285 | |
Recurring [Member] | Level 1 [Member] | Money Market Funds [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 27 | |
Recurring [Member] | Level 1 [Member] | Corporate Obligations [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 0 | |
Recurring [Member] | Level 1 [Member] | Bank Notes / Certificates of Deposit / Time Deposits [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 0 | |
Recurring [Member] | Level 1 [Member] | Repurchase Agreements [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 0 | |
Recurring [Member] | Level 2 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 4,354 | |
Restricted cash and short-term investments | 141 | |
Long-term investments | 0 | |
Total | 4,495 | |
Recurring [Member] | Level 2 [Member] | Money Market Funds [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 0 | |
Recurring [Member] | Level 2 [Member] | Corporate Obligations [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 1,301 | |
Recurring [Member] | Level 2 [Member] | Bank Notes / Certificates of Deposit / Time Deposits [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 2,803 | |
Recurring [Member] | Level 2 [Member] | Repurchase Agreements [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 250 | |
Recurring [Member] | Level 3 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 0 | |
Restricted cash and short-term investments | 0 | |
Long-term investments | 0 | |
Total | 0 | |
Recurring [Member] | Level 3 [Member] | Money Market Funds [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 0 | |
Recurring [Member] | Level 3 [Member] | Corporate Obligations [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 0 | |
Recurring [Member] | Level 3 [Member] | Bank Notes / Certificates of Deposit / Time Deposits [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 0 | |
Recurring [Member] | Level 3 [Member] | Repurchase Agreements [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 0 | |
American Airlines, Inc. [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 4,370 | $ 4,768 |
American Airlines, Inc. [Member] | Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 4,370 | |
Restricted cash and short-term investments | 183 | |
Long-term investments | 216 | |
Total | 4,769 | |
American Airlines, Inc. [Member] | Recurring [Member] | Money Market Funds [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 17 | |
American Airlines, Inc. [Member] | Recurring [Member] | Corporate Obligations [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 1,301 | |
American Airlines, Inc. [Member] | Recurring [Member] | Corporate Obligations [Member] | Maturity Dates Exceeding One Year [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 100 | |
American Airlines, Inc. [Member] | Recurring [Member] | Bank Notes / Certificates of Deposit / Time Deposits [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 2,802 | |
American Airlines, Inc. [Member] | Recurring [Member] | Bank Notes / Certificates of Deposit / Time Deposits [Member] | Maturity Dates Exceeding One Year [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 475 | |
American Airlines, Inc. [Member] | Recurring [Member] | Repurchase Agreements [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 250 | |
American Airlines, Inc. [Member] | Recurring [Member] | Level 1 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 17 | |
Restricted cash and short-term investments | 42 | |
Long-term investments | 216 | |
Total | 275 | |
American Airlines, Inc. [Member] | Recurring [Member] | Level 1 [Member] | Money Market Funds [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 17 | |
American Airlines, Inc. [Member] | Recurring [Member] | Level 1 [Member] | Corporate Obligations [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 0 | |
American Airlines, Inc. [Member] | Recurring [Member] | Level 1 [Member] | Bank Notes / Certificates of Deposit / Time Deposits [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 0 | |
American Airlines, Inc. [Member] | Recurring [Member] | Level 1 [Member] | Repurchase Agreements [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 0 | |
American Airlines, Inc. [Member] | Recurring [Member] | Level 2 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 4,353 | |
Restricted cash and short-term investments | 141 | |
Long-term investments | 0 | |
Total | 4,494 | |
American Airlines, Inc. [Member] | Recurring [Member] | Level 2 [Member] | Money Market Funds [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 0 | |
American Airlines, Inc. [Member] | Recurring [Member] | Level 2 [Member] | Corporate Obligations [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 1,301 | |
American Airlines, Inc. [Member] | Recurring [Member] | Level 2 [Member] | Bank Notes / Certificates of Deposit / Time Deposits [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 2,802 | |
American Airlines, Inc. [Member] | Recurring [Member] | Level 2 [Member] | Repurchase Agreements [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 250 | |
American Airlines, Inc. [Member] | Recurring [Member] | Level 3 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 0 | |
Restricted cash and short-term investments | 0 | |
Long-term investments | 0 | |
Total | 0 | |
American Airlines, Inc. [Member] | Recurring [Member] | Level 3 [Member] | Money Market Funds [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 0 | |
American Airlines, Inc. [Member] | Recurring [Member] | Level 3 [Member] | Corporate Obligations [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 0 | |
American Airlines, Inc. [Member] | Recurring [Member] | Level 3 [Member] | Bank Notes / Certificates of Deposit / Time Deposits [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | 0 | |
American Airlines, Inc. [Member] | Recurring [Member] | Level 3 [Member] | Repurchase Agreements [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term investments | $ 0 | |