Property and Equipment (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) ship	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Property and Equipment
Capitalized interest cost	$ 59.1	$ 56.5	$ 49.6
Impairment losses	635.5
Lease, right-of-use asset impairment	65.9
Three Pullmantur Ships | Disposal Group, Held-for-sale, Not Discontinued Operations
Property and Equipment
Impairment losses	$ 171.3
Number of ships impaired, held-for-sale | ship	3
Construction in Progress
Property and Equipment
Long-lived asset impairment	$ 91.5
Azamara | Disposal Group, Held-for-sale, Not Discontinued Operations
Property and Equipment
Impairment losses	$ 166.8
Number of ships impaired, held-for-sale | ship	3