Financial Instruments and Fair Value Measurements - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2014
Asset-backed Securities | Minimum
Fair Value [Line Items]
Available-for-sale securities remaining maturities	1 year
Asset-backed Securities | Maximum
Fair Value [Line Items]
Available-for-sale securities remaining maturities	40 years
Corporate Debt | Minimum
Fair Value [Line Items]
Available-for-sale securities remaining maturities	1 year
Corporate Debt | Maximum
Fair Value [Line Items]
Available-for-sale securities remaining maturities	21 years
Auction Rate Securities | Minimum
Fair Value [Line Items]
Available-for-sale securities remaining maturities	18 years
Auction Rate Securities | Maximum
Fair Value [Line Items]
Available-for-sale securities remaining maturities	32 years
CDARS | Maximum
Fair Value [Line Items]
Available-for-sale securities remaining maturities	1 year
U.S. Government and Other Securities | Maximum
Fair Value [Line Items]
Available-for-sale securities remaining maturities	1 year
EETC | Maximum
Fair Value [Line Items]
Available-for-sale securities maturity, year	2019
6% convertible junior subordinated debentures due 2030
Fair Value [Line Items]
Debt instrument convertible stated interest rate	6.00%
Debt instrument maturity year	2030
4.5% Convertible Notes Due 2015
Fair Value [Line Items]
Debt instrument convertible stated interest rate	4.50%
Debt instrument maturity year	2015