Changes in Accumulated Other Comprehensive (Loss) Income - Reclassifications (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Reclassifications out of accumulated other comprehensive loss
Interest expense, net of interest capitalized	$ (66,819)	$ (60,100)	$ (213,598)	$ (193,931)
Depreciation and amortization expenses	(210,742)	(192,448)	(617,678)	(579,063)
Other income	29,218	39,214	166,000	168,137
Fuel	(199,848)	(230,818)	(607,689)	(718,081)
Net income	228,787	490,248	458,984	654,378
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income (Loss) into Income
Reclassifications out of accumulated other comprehensive loss
Net income	(78,164)	(6,221)	(204,332)	(19,526)
(Loss) gain on cash flow derivative hedges: | Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income (Loss) into Income
Reclassifications out of accumulated other comprehensive loss
Net income	(77,810)	(5,790)	(202,978)	(16,236)
(Loss) gain on cash flow derivative hedges: | Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income (Loss) into Income | Cross currency swaps
Reclassifications out of accumulated other comprehensive loss
Interest expense, net of interest capitalized	0	0	0	(261)
(Loss) gain on cash flow derivative hedges: | Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income (Loss) into Income | Interest rate swaps
Reclassifications out of accumulated other comprehensive loss
Interest expense, net of interest capitalized	(10,276)	(3,106)	(27,024)	(9,312)
(Loss) gain on cash flow derivative hedges: | Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income (Loss) into Income | Foreign currency forward contracts
Reclassifications out of accumulated other comprehensive loss
Interest expense, net of interest capitalized	0	0	0	(57)
Depreciation and amortization expenses	(752)	(450)	(2,153)	(1,348)
Other income	(239)	(238)	(715)	(4,052)
(Loss) gain on cash flow derivative hedges: | Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income (Loss) into Income | Foreign currency collar options
Reclassifications out of accumulated other comprehensive loss
Depreciation and amortization expenses	(568)	0	(1,003)	0
(Loss) gain on cash flow derivative hedges: | Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income (Loss) into Income | Fuel swaps
Reclassifications out of accumulated other comprehensive loss
Fuel	(65,975)	(1,996)	(172,083)	(1,206)
Amortization of defined benefit plans: | Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income (Loss) into Income
Reclassifications out of accumulated other comprehensive loss
Actuarial loss	(354)	(222)	(1,061)	(666)
Prior service costs	0	(209)	(293)	(627)
Net income	(354)	(431)	(1,354)	(1,293)
Accumulated Translation Adjustment | Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income (Loss) into Income
Reclassifications out of accumulated other comprehensive loss
Other income	$ 0	$ 0	$ 0	$ (1,997)