Changes in Accumulated Other Comprehensive (Loss) Income - Reclassifications (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Reclassifications out of accumulated other comprehensive loss
Interest expense, net of interest capitalized	$ (60,100)	$ (79,654)	$ (193,931)	$ (256,713)
Depreciation and amortization expenses	(192,448)	(188,541)	(579,063)	(564,089)
Other income (expense)	(39,214)	(78,508)	(168,137)	(256,505)
Fuel	(230,818)	(215,686)	(718,081)	(689,809)
Net income	490,248	365,701	654,378	466,674
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income
Reclassifications out of accumulated other comprehensive loss
Net income	(3,115)	28,888	(10,214)	50,697
(Loss) gain on cash flow derivative hedges: | Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income
Reclassifications out of accumulated other comprehensive loss
Net income	(2,684)	29,535	(6,924)	52,639
(Loss) gain on cash flow derivative hedges: | Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income | Cross currency swaps
Reclassifications out of accumulated other comprehensive loss
Interest expense, net of interest capitalized	0	(890)	(261)	(2,641)
(Loss) gain on cash flow derivative hedges: | Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income | Foreign currency forward contracts
Reclassifications out of accumulated other comprehensive loss
Interest expense, net of interest capitalized	0	(217)	(57)	(222)
Depreciation and amortization expenses	(450)	(449)	(1,348)	(1,348)
Other income (expense)	(238)	19,089	(4,052)	18,612
(Loss) gain on cash flow derivative hedges: | Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income | Fuel swaps
Reclassifications out of accumulated other comprehensive loss
Fuel	(1,996)	12,002	(1,206)	38,238
Amortization of defined benefit plans: | Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income
Reclassifications out of accumulated other comprehensive loss
Actuarial loss	(222)	(438)	(666)	(1,315)
Prior service costs	(209)	(209)	(627)	(627)
Net income	(431)	(647)	(1,293)	(1,942)
Release of foreign cumulative translation due to sale of business: | Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income
Reclassifications out of accumulated other comprehensive loss
Other income (expense)	$ 0	$ 0	$ (1,997)	$ 0