Financial Instruments and Fair Value Measurements - Additional Information (Detail)	6 Months Ended											3 Months Ended
	Jun. 30, 2014 Asset-backed Securities Minimum	Jun. 30, 2014 Asset-backed Securities Maximum	Jun. 30, 2014 Corporate Debt Minimum	Jun. 30, 2014 Corporate Debt Maximum	Jun. 30, 2014 Auction Rate Securities Minimum	Jun. 30, 2014 Auction Rate Securities Maximum	Jun. 30, 2014 CDARS Maximum	Jun. 30, 2014 U.S. Government and Other Securities Minimum	Jun. 30, 2014 U.S. Government and Other Securities Maximum	Jun. 30, 2014 EETC Maximum	Jun. 30, 2014 6% convertible junior subordinated debentures due 2030	Jun. 30, 2014 4.5% Convertible Notes Due 2015
Fair Value [Line Items]
Available-for-sale securities remaining maturities	1 year	40 years	1 year	7 years	24 years	32 years	1 year	1 year	4 years
Available-for-sale securities maturity, year										2019
Debt instrument convertible stated interest rate											6.00%	4.50%
Debt instrument maturity year											2030	2015