General (Details) $ / shares in Units, € in Billions					1 Months Ended		9 Months Ended
		Jul. 09, 2020 $ / shares shares	Jun. 30, 2020 USD ($)	Jun. 30, 2020 EUR (€)	Oct. 31, 2020 USD ($) $ / shares shares	Jun. 30, 2020 GBP (£)	Sep. 30, 2020 USD ($) brand $ / shares shares	Sep. 30, 2020 GBP (£)	Sep. 30, 2020 GBP (£) brand shares	Aug. 31, 2020 USD ($)	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2019 GBP (£) shares	Dec. 31, 2018	Jul. 31, 2018
Schedule of Equity Method Investments [Line Items]
Number of cruise brands | brand							4		4
Interest acquired		33.30%
Common stock, shares issued (in shares) | shares		5,200,000					242,502,983		242,502,983		236,547,842	236,547,842
Common stock, par value (in dollars per share) | $ / shares		$ 0.01					$ 0.01				$ 0.01
Liquidity							$ 3,700,000,000
Cash and cash equivalents							3,016,788,000				$ 243,738,000
Increase in liquidity							8,100,000,000
Long-term debt							6,200,000,000
Commercial paper | £						£ 300,000,000.0		£ 300,000,000.0
Increase in liquidity due to deferral of existing debt amortization							900,000,000
Debt covenant, monthly minimum liquidity							500,000,000.0
Maximum additional collateral or reserves potentially needed							75,000,000
Collateral amount							80,000,000
Convertible notes
Schedule of Equity Method Investments [Line Items]
Debt instrument, face amount			$ 1,150,000,000				$ 1,150,000,000
Interest rate	[1]						4.25%		4.25%
Commercial Paper
Schedule of Equity Method Investments [Line Items]
Borrowings outstanding							$ 387,900,000		£ 300,000,000.0			£ 1,400,000,000
Hapag-Lloyd Cruises | TUI Cruises
Schedule of Equity Method Investments [Line Items]
Purchase price			1,300,000,000	€ 1.2
Silversea Cruises
Schedule of Equity Method Investments [Line Items]
Percentage of business acquired													66.70%	66.70%
Subsequent Event
Schedule of Equity Method Investments [Line Items]
Common stock, par value (in dollars per share) | $ / shares					$ 0.01
Number of shares sold (in shares) | shares					9,600,000
Sale of stock, price per share (in dollars per share) | $ / shares					$ 60.00
Proceeds from sale of stock, gross					$ 575,000,000
Debt covenant, monthly minimum liquidity					350,000,000.0
Subsequent Event | Senior Convertible Notes Due 2023 | Convertible notes
Schedule of Equity Method Investments [Line Items]
Debt instrument, face amount					$ 575,000,000
Interest rate					2.875%
Revolving Credit Facility
Schedule of Equity Method Investments [Line Items]
Increase to revolving credit facility							600,000,000
Long-term debt			$ 11,000,000,000.0
Line of Credit | Term Loan Facility, $700 Million
Schedule of Equity Method Investments [Line Items]
Maximum borrowing capacity							$ 700,000,000			$ 700,000,000
TUI Cruises
Schedule of Equity Method Investments [Line Items]
Investment in a joint venture, percentage of interest							50.00%		50.00%
TUI Cruises | Not Primary Beneficiary
Schedule of Equity Method Investments [Line Items]
Investment in a joint venture, percentage of interest							50.00%		50.00%
Pullmantur Holdings
Schedule of Equity Method Investments [Line Items]
Investment in a joint venture, percentage of interest							49.00%		49.00%

[1] Interest rates based on outstanding loan balance as of September 30, 2020 and, for variable rate debt, include either LIBOR or EURIBOR plus the applicable margin.