Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Gross amount of port costs included in passenger ticket revenues	$ 158.7	$ 156.8	$ 443.1	$ 425.6
Reclassification of dividends received from unconsolidated affiliates				$ 5.3
Adjustments for New Accounting Pronouncement [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification adjustment related to debt issuance costs					$ 139.8