Debt (Narrative) (Details)		1 Months Ended													3 Months Ended	10 Months Ended	12 Months Ended				25 Months Ended	29 Months Ended	31 Months Ended	33 Months Ended	34 Months Ended		43 Months Ended	78 Months Ended	109 Months Ended
	Oct. 01, 2020	Apr. 30, 2022	Mar. 31, 2021 USD ($)	Oct. 31, 2020 USD ($) $ / shares	Sep. 30, 2020	Aug. 31, 2020 USD ($)	Jun. 30, 2020 USD ($) $ / shares	Jun. 30, 2020 GBP (£)	May 31, 2020 USD ($) ship	Mar. 31, 2020 USD ($) board_member	Sep. 30, 2019	Aug. 31, 2019 USD ($)	Apr. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2023	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017	May 31, 2022	Mar. 14, 2023 day	Aug. 14, 2023 day	Mar. 14, 2023 day	Aug. 14, 2023 day	Feb. 28, 2023	Dec. 31, 2025	Jun. 30, 2026	Jun. 30, 2028	Dec. 31, 2021 USD ($)	Dec. 31, 2020 GBP (£)	Feb. 29, 2020 USD ($)	May 31, 2019 USD ($)	Apr. 29, 2019 USD ($)	Jul. 31, 2018 USD ($)	Nov. 30, 2017 EUR (€)
Long-Term Debt
Collateral																	$ 91,000,000
Loss on extinguishment of secured senior term loan																	41,109,000	$ 6,326,000	$ 0
Short-term debt amount outstanding								£ 300,000,000.0				$ 2,900,000,000		$ 1,200,000,000
Deferred amortization of debt, debt holiday																	$ 900,000,000
Deferred debt amortization period																	4 years
Credit agency fees, percentage of outstanding loan balance																	2.97%
Scenario, Forecast
Long-Term Debt
Collateral																														$ 33,300,000
Deferred amortization of debt, debt holiday			$ 800,000,000												$ 800,000,000
Deferred debt amortization period		5 years
Debt covenant, minimum monthly liquidity requirement															500,000,000
Minimum additional capital to be raised to reduce minimum liquidity covenant			500,000,000												500,000,000
Deferred principal payments			1,100,000,000												1,100,000,000
Debt covenant, minimum monthly liquidity amount if additional capital is raised															350,000,000.0
Convertible Notes Due 2023
Long-Term Debt
Proceeds allocated to paid-in-capital							$ 209,000,000.0
Debt issuance costs							33,100,000
Issuance costs allocated to paid-in capital							6,200,000
Convertible Notes Due 2023 | Long-term debt
Long-Term Debt
Proceeds from debt issuance							907,900,000
Senior Convertible Notes Due 2023
Long-Term Debt
Proceeds allocated to paid-in-capital							101,900,000
Debt issuance costs							10,100,000
Issuance costs allocated to paid-in capital							1,800,000
Senior Convertible Notes Due 2023 | Long-term debt
Long-Term Debt
Proceeds from debt issuance							$ 463,000,000.0
Silversea Cruises
Long-Term Debt
Principal													$ 700,000,000																						$ 700,000,000
Non-Export Credit Facilities | Scenario, Forecast
Long-Term Debt
Long-term debt			4,900,000,000												4,900,000,000
Export Credit Facilities | Scenario, Forecast
Long-Term Debt
Long-term debt			$ 6,200,000,000												$ 6,200,000,000
Revolving Credit Facility
Long-Term Debt
Maximum borrowing capacity																	$ 3,500,000,000
Revolving Credit Facility | Unsecured Revolving Credit Facility Due 2024
Long-Term Debt
Maximum borrowing capacity																	$ 1,900,000,000															$ 1,700,000,000
Increase in borrowing capacity										$ 200,000,000
Long term debt, facility fee (as a percent)																	0.20%
Revolving Credit Facility | Unsecured Revolving Credit Facility Due 2022
Long-Term Debt
Maximum borrowing capacity																	$ 1,600,000,000															$ 1,200,000,000
Increase in borrowing capacity										400,000,000
Long term debt, facility fee (as a percent)																	0.20%
Revolving Credit Facility | $1.4 billion unsecured revolving credit facility
Long-Term Debt
Principal													1,700,000,000																					$ 1,400,000,000
Long term debt, facility fee (as a percent)																	0.125%
Revolving Credit Facility | $1.15 billion unsecured revolving credit facility
Long-Term Debt
Principal																																	$ 1,150,000,000
Revolving Credit Facility | LIBOR | Unsecured Revolving Credit Facility Due 2024
Long-Term Debt
Margin on floating rate base (as a percent)																	1.30%
Revolving Credit Facility | LIBOR | Unsecured Revolving Credit Facility Due 2022
Long-Term Debt
Margin on floating rate base (as a percent)																	1.30%
Revolving Credit Facility | LIBOR | $1.4 billion unsecured revolving credit facility
Long-Term Debt
Margin on floating rate base (as a percent)																	1.00%
Unsecured term loans | Maximum
Long-Term Debt
Long term debt, stated interest rate (as a percent)																	5.41%														5.41%
Unsecured term loans | Minimum
Long-Term Debt
Long term debt, stated interest rate (as a percent)																	2.53%														2.53%
Unsecured term loans | Celebrity Apex Unsecured Term Loan
Long-Term Debt
Maximum borrowing capacity										$ 722,200,000
Debt instrument, term										12 years
Long term debt, stated interest rate (as a percent)										3.23%
Unsecured term loans | Silver Moon Credit Agreement
Long-Term Debt
Principal																	$ 300,000,000
Unsecured term loans | Silver Moon Credit Agreement | Scenario, Forecast
Long-Term Debt
Repayment advance notice																												90 days
Periodic payment, percentage of principal																													4.17%
Unsecured term loans | Term Loan Due 2023
Long-Term Debt
Principal																	130,000,000.0
Unsecured term loans | Novation Agreement
Long-Term Debt
Maximum borrowing capacity													$ 908,000,000.0
Debt instrument, term													12 years
Long term debt, stated interest rate (as a percent)													3.45%
Unsecured term loans | Unsecured Term Loan Facility
Long-Term Debt
Principal																	$ 97,900,000																			€ 80,000,000.0
Unsecured term loans | LIBOR | Silver Moon Credit Agreement
Long-Term Debt
Margin on floating rate base (as a percent)																	2.00%
Unsecured term loans | Euro Interbank Offered Rate (EURIBOR) | Unsecured Term Loan Facility
Long-Term Debt
Margin on floating rate base (as a percent)																	1.195%
USD Secured Term Loan | Secured Term Loan
Long-Term Debt
Increase in borrowing capacity									$ 150,000,000
Debt instrument, term										364 days
Principal									2,350,000,000	$ 2,200,000,000
Extension term										364 days
Extension fee percentage										1.00%
Duration fee percentage							0.25%
Number of board members | board_member										2
USD Secured Term Loan | Secured Term Loan | Director | Board Member One
Long-Term Debt
Payments to related parties for services provided										$ 100,000,000
USD Secured Term Loan | Secured Term Loan | Director | Board Member Two
Long-Term Debt
Payments to related parties for services provided										$ 100,000,000
USD Secured Term Loan | LIBOR | Secured Term Loan
Long-Term Debt
Margin on floating rate base (as a percent)					2.50%					2.25%
USD Secured Term Loan | LIBOR | Secured Term Loan | Scenario, Forecast
Long-Term Debt
Margin on floating rate base (as a percent)			2.75%
Secured senior notes | Maximum
Long-Term Debt
Long term debt, stated interest rate (as a percent)																	11.50%														11.50%
Secured senior notes | Minimum
Long-Term Debt
Long term debt, stated interest rate (as a percent)																	7.25%														7.25%
Secured senior notes | Senior Secured Notes
Long-Term Debt
Principal									3,320,000,000
Net proceeds from debt									$ 3,200,000,000
Percentage of equity interests pledged as collateral									100.00%
Number of ships owned by subsidiaries | ship									28
Secured senior notes | Senior Secured Notes | Maximum
Long-Term Debt
Collateral									$ 1,660,000,000
Secured senior notes | Senior Secured Notes Due 2023
Long-Term Debt
Long term debt, stated interest rate (as a percent)									10.875%
Principal									$ 1,000,000,000.0
Secured senior notes | Senior Secured Notes Due 2023 | Scenario, Forecast
Long-Term Debt
Percentage of principal amount to be redeemed																100.00%										100.00%
Secured senior notes | Senior Secured Notes Due 2025
Long-Term Debt
Long term debt, stated interest rate (as a percent)									11.50%
Principal									$ 2,320,000,000
Secured senior notes | Senior Secured Notes Due 2025 | Scenario, Forecast
Long-Term Debt
Percentage of principal amount to be redeemed																					100.00%						40.00%
Unsecured senior notes | Maximum
Long-Term Debt
Long term debt, stated interest rate (as a percent)																	9.13%														9.13%
Unsecured senior notes | Minimum
Long-Term Debt
Long term debt, stated interest rate (as a percent)																	2.65%														2.65%
Unsecured senior notes | Senior Guaranteed Notes
Long-Term Debt
Long term debt, stated interest rate (as a percent)							9.125%
Principal							$ 1,000,000,000.0
Percentage of equity interests pledged as collateral							100.00%
Convertible notes
Long-Term Debt
Principal																	$ 1,725,000,000
Convertible notes | Maximum
Long-Term Debt
Long term debt, stated interest rate (as a percent)																	4.25%														4.25%
Convertible notes | Minimum
Long-Term Debt
Long term debt, stated interest rate (as a percent)																	2.88%														2.88%
Convertible notes | Convertible Notes Due 2023
Long-Term Debt
Long term debt, stated interest rate (as a percent)							4.25%
Principal							$ 1,150,000,000
Percentage of principal amount to be redeemed							100.00%	100.00%
Conversion ratio							0.0138672	0.0138672
Conversion price (in dollars per share) | $ / shares							$ 72.11
Convertible notes | Convertible Notes Due 2023 | Scenario, Forecast
Long-Term Debt
Number of trading days | day																						20
Consecutive trading days | day																						30		10
Percentage of stock price																						130.00%		98.00%
Number of days to convert debt | day																								5
Convertible notes | Senior Convertible Notes Due 2023
Long-Term Debt
Long term debt, stated interest rate (as a percent)				2.875%
Principal				$ 575,000,000
Percentage of principal amount to be redeemed	100.00%
Conversion ratio				0.0121212
Conversion price (in dollars per share) | $ / shares				$ 82.50
Convertible notes | Senior Convertible Notes Due 2023 | Scenario, Forecast
Long-Term Debt
Number of trading days | day																							20
Consecutive trading days | day																							30		10
Percentage of stock price																							130.00%		98.00%
Number of days to convert debt | day																									5
Loans Payable
Long-Term Debt
Loss on extinguishment of secured senior term loan																	$ 6,300,000
Loans Payable | Term Loan
Long-Term Debt
Principal													$ 1,000,000,000.0
Loans Payable | LIBOR | Term Loan
Long-Term Debt
Margin on floating rate base (as a percent)																	1.075%
Revolving Credit Facility
Long-Term Debt
Long-term debt																	$ 11,200,000,000
Minimum fixed charge coverage ratio																	125.00%														125.00%
Credit agreement | Term Loan Facility, $700 Million
Long-Term Debt
Maximum borrowing capacity						$ 700,000,000											$ 700,000,000
Term loan facility increase limit						$ 300,000,000
Credit agreement | LIBOR | Term Loan Facility, $700 Million
Long-Term Debt
Margin on floating rate base (as a percent)						3.75%
Up-front payment arrangement | Maximum
Long-Term Debt
Credit agency fees, percentage of loan amount payable																	2.37%
Up-front payment arrangement | Minimum
Long-Term Debt
Credit agency fees, percentage of loan amount payable																	2.35%
BpiFAE | Celebrity Apex Unsecured Term Loan | Celebrity Apex
Long-Term Debt
Percentage of unsecured term loan guaranteed by an export credit agency										100.00%
Euler Hermes | Unsecured term loans
Long-Term Debt
Percentage of unsecured term loan guaranteed by an export credit agency											95.00%									95.00%
Euler Hermes | Unsecured term loans | Novation Agreement
Long-Term Debt
Percentage of unsecured term loan guaranteed by an export credit agency													95.00%
Unsecured UK Commercial paper
Long-Term Debt
Borrowings outstanding																	$ 409,900,000														£ 300,000,000.0
Commercial paper
Long-Term Debt
Debt instrument, term																		21 days
Borrowings outstanding																		$ 1,400,000,000
Weighted average interest rate																		2.19%