Fair Value Measurements and Derivative Instruments - Designated Cash Flow Hedges (Details) - Cash flow hedge - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Effect of derivative instruments involved in hedging on the consolidated financial statements
Amount of Gain (Loss) Recognized in Other Comprehensive Income on Derivative (Effective Portion)	$ 138,738	$ (23,521)	$ (183,646)	$ (84,000)
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion)	(63,737)	(2,882)	(125,170)	(10,447)
Location of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income (Ineffective Portion)	(417)	2,011	(197)	340
Cross currency swaps | Interest expense, net of interest capitalized
Effect of derivative instruments involved in hedging on the consolidated financial statements
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion)	0	0	0	(261)
Interest rate swaps | Other income (expense)
Effect of derivative instruments involved in hedging on the consolidated financial statements
Location of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income (Ineffective Portion)	183	(76)	221	(95)
Interest rate swaps | Interest expense, net of interest capitalized
Effect of derivative instruments involved in hedging on the consolidated financial statements
Amount of Gain (Loss) Recognized in Other Comprehensive Income on Derivative (Effective Portion)	29,666	(35,301)	(6,149)	(72,951)
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion)	(9,962)	(3,078)	(16,748)	(6,206)
Foreign currency forward contracts | Other income (expense)
Effect of derivative instruments involved in hedging on the consolidated financial statements
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion)	(239)	(238)	(477)	(3,814)
Location of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income (Ineffective Portion)	0	(7)	0	(27)
Foreign currency forward contracts | Depreciation and amortization expenses
Effect of derivative instruments involved in hedging on the consolidated financial statements
Amount of Gain (Loss) Recognized in Other Comprehensive Income on Derivative (Effective Portion)	42,229	(10,437)	(130,593)	(9,243)
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion)	(685)	(450)	(1,402)	(899)
Foreign currency forward contracts | Interest expense, net of interest capitalized
Effect of derivative instruments involved in hedging on the consolidated financial statements
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion)	0	0	0	(57)
Foreign currency collar options | Depreciation and amortization expenses
Effect of derivative instruments involved in hedging on the consolidated financial statements
Amount of Gain (Loss) Recognized in Other Comprehensive Income on Derivative (Effective Portion)	240	(6,127)	(64,593)	(8,734)
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion)	(435)	0	(435)	0
Fuel swaps | Swaps | Other income (expense)
Effect of derivative instruments involved in hedging on the consolidated financial statements
Location of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income (Ineffective Portion)	(600)	2,094	(418)	462
Fuel swaps | Swaps | Fuel cost
Effect of derivative instruments involved in hedging on the consolidated financial statements
Amount of Gain (Loss) Recognized in Other Comprehensive Income on Derivative (Effective Portion)	66,603	28,344	17,689	6,928
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion)	$ (52,416)	$ 884	$ (106,108)	$ 790