Fair Value Measurements and Derivative Instruments (Designated Cash Flow Hedges) (Details) - Cash flow hedge - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Effect of derivative instruments involved in fair value hedging on the consolidated financial statements
Amount of Gain (Loss) Recognized in Other Comprehensive Income on Derivatives (Effective Portion)	$ 73,998	$ (697,671)
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion)	(337,250)	(291,624)
Amount of Gain (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness testing)	(810)	(449)
Interest rate swaps
Effect of derivative instruments involved in fair value hedging on the consolidated financial statements
Amount of Gain (Loss) Recognized in Other Comprehensive Income on Derivatives (Effective Portion)	(31,049)	(52,602)
Interest rate swaps | Interest Expense
Effect of derivative instruments involved in fair value hedging on the consolidated financial statements
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion)	(41,480)	(36,401)
Interest rate swaps | Other income (expense)
Effect of derivative instruments involved in fair value hedging on the consolidated financial statements
Amount of Gain (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness testing)	0	38
Foreign currency forward contracts
Effect of derivative instruments involved in fair value hedging on the consolidated financial statements
Amount of Gain (Loss) Recognized in Other Comprehensive Income on Derivatives (Effective Portion)	(51,092)	(141,470)
Foreign currency forward contracts | Depreciation and amortization expenses
Effect of derivative instruments involved in fair value hedging on the consolidated financial statements
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion)	(8,114)	(2,871)
Foreign currency forward contracts | Other income (expense)
Effect of derivative instruments involved in fair value hedging on the consolidated financial statements
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion)	(14,342)	7,580
Amount of Gain (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness testing)	(59)	0
Foreign currency forward contracts | Other Indirect Operating Expense
Effect of derivative instruments involved in fair value hedging on the consolidated financial statements
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion)	(207)	0
Foreign currency collar options
Effect of derivative instruments involved in fair value hedging on the consolidated financial statements
Amount of Gain (Loss) Recognized in Other Comprehensive Income on Derivatives (Effective Portion)	0	(64,559)
Foreign currency collar options | Depreciation and amortization expenses
Effect of derivative instruments involved in fair value hedging on the consolidated financial statements
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion)	(2,408)	(1,605)
Fuel Swaps
Effect of derivative instruments involved in fair value hedging on the consolidated financial statements
Amount of Gain (Loss) Recognized in Other Comprehensive Income on Derivatives (Effective Portion)	156,139	(439,040)
Fuel Swaps | Other income (expense)
Effect of derivative instruments involved in fair value hedging on the consolidated financial statements
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion)	13,685	(9,583)
Amount of Gain (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness testing)	(751)	(487)
Fuel Swaps | Fuel cost
Effect of derivative instruments involved in fair value hedging on the consolidated financial statements
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion)	$ (284,384)	$ (248,744)