Summary of Significant Accounting Policies (Narrative) (Details) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020 USD ($) brand $ / shares	Sep. 30, 2020 USD ($) $ / shares	Jun. 30, 2020 USD ($) $ / shares	Mar. 31, 2020 USD ($) $ / shares	Dec. 31, 2019 USD ($) $ / shares	Sep. 30, 2019 USD ($) $ / shares	Jun. 30, 2019 USD ($) $ / shares	Mar. 31, 2019 USD ($) $ / shares	Dec. 31, 2020 USD ($) brand segment $ / shares	Dec. 31, 2019 USD ($) $ / shares	Dec. 31, 2018 USD ($) $ / shares
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating (Loss) income	$ (1,016,549)	$ (996,114)	$ (1,282,487)	$ (1,306,407)	$ 299,425	$ 890,792	$ 573,653	$ 318,831	$ (4,601,557)	$ 2,082,701	$ 1,894,801
Net (Loss) Income									$ (5,775,130)	$ 1,907,600	$ 1,815,792
Basic (loss) earnings per share (in dollars per share) | $ / shares	$ (6.09)	$ (6.29)	$ (7.83)	$ (6.91)	$ 1.31	$ 4.21	$ 2.26	$ 1.19	$ (27.05)	$ 8.97	$ 8.60
Diluted (loss) earnings per share (in dollars per share) | $ / shares	$ (6.09)	$ (6.29)	$ (7.83)	$ (6.91)	$ 1.30	$ 4.20	$ 2.25	$ 1.19	$ (27.05)	$ 8.95	$ 8.56
Exchange gains (losses) recorded in other income (expense)									$ (1,500)	$ 400	$ 57,600
Derivative instrument, credit risk exposure									$ 26,900	0
Number of cruise brands | brand	4								4
Number of operating segments | segment									1
Right-of-use asset	$ 599,985				$ 687,555				$ 599,985	687,555
Operating lease liability	$ 666,553				698,617				$ 666,553	698,617
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use asset					801,800					801,800
Operating lease liability					$ 820,500					820,500
Change In Property, Plant And Equipment, Useful Lives
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating (Loss) income										4,600
Net (Loss) Income										$ 4,600
Basic (loss) earnings per share (in dollars per share) | $ / shares										$ 0.02
Diluted (loss) earnings per share (in dollars per share) | $ / shares										$ 0.02
Lower Limit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Investment in a joint venture, percentage of interest	20.00%								20.00%
Upper Limit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Investment in a joint venture, percentage of interest	50.00%								50.00%
Ships
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Payments for capital investment										$ 538,000
Ships | Oasis Of The Seas
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property, plant and equipment, useful life					35 years					35 years	30 years
Residual value, percentage					10.00%					10.00%	15.00%
Payments for capital investment										$ 170,000
Ships | Lower Limit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property, plant and equipment, useful life									30 years
Residual value, percentage	10.00%								10.00%
Drydock services period									30 months
Ships | Upper Limit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property, plant and equipment, useful life									35 years
Residual value, percentage	15.00%								15.00%
Drydock services period									60 months
Media advertising
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Advertising costs									$ 138,100	309,400	$ 255,700
Brochure, production and direct mail costs
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Advertising costs									$ 69,100	$ 156,000	$ 133,400
TUI Cruises
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Investment in a joint venture, percentage of interest	50.00%								50.00%
Pullmantur
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Investment in a joint venture, percentage of interest	49.00%								49.00%