Summary of Significant Accounting Policies (Policies)	9 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 30, 2019
Accounting Policies [Abstract]
Basis for Preparation of Consolidated Financial Statements	Basis for Preparation of Consolidated Financial Statements The unaudited consolidated financial statements are presented pursuant to the rules and regulations of the Securities and Exchange Commission. In our opinion, these statements include all adjustments necessary for a fair statement of the results of the interim periods reported herein. Adjustments consist only of normal recurring items, except for any items discussed in the notes below. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) have been condensed or omitted as permitted by such rules and regulations. Estimates are required for the preparation of financial statements in accordance with these principles. Actual results could differ from these estimates. Refer to Note 2. Summary of Significant Accounting Policies in this Quarterly Report on Form 10-Q and in our Annual Report on Form 10-K for the year ended December 31, 2018 for a discussion of our significant accounting policies.
Basis of Consolidation	All significant intercompany accounts and transactions are eliminated in consolidation. We consolidate entities over which we have control, usually evidenced by a direct ownership interest of greater than 50%, and variable interest entities where we are determined to be the primary beneficiary. Refer to Note 7. Other Assets for further information regarding our variable interest entities. We consolidate the operating results of Silversea Cruises on a three-month reporting lag to allow for more timely preparation of our consolidated financial statements. No material events or other transactions involving Silversea Cruises have occurred from July 1, 2019 through September 30, 2019 that would require further disclosure or adjustment to our consolidated financial statements as of and for the quarter ended September 30, 2019. For affiliates we do not control but over which we have significant influence on financial and operating policies, usually evidenced by a direct ownership interest from 20% to 50%, the investment is accounted for using the equity method.
Adoption of Accounting Pronouncements; Recent Accounting Pronouncements	Adoption of Accounting Pronouncements Leases On January 1, 2019, we adopted the guidance codified in Accounting Standard Codification ("ASC") 842, Leases ("ASC 842") using the modified retrospective approach and elected the optional transition method, which allows entities to initially apply the standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. Upon adoption, we applied the guidance to all existing leases. For leases with a term greater than 12 months, the new guidance requires the lease rights and obligations arising from the leasing arrangements, including operating leases, to be recognized as assets and liabilities on the balance sheet. Upon adoption of the new guidance, the most significant impact was the recognition of right-of-use assets and lease liabilities relating to operating leases in the amounts of $801.8 million and $820.5 million, respectively, reported within Operating lease right-of-use assets and Long-term operating lease liabilities, respectively, with the current portion of the liability reported within Current portion of operating lease liabilities, in our consolidated balance sheet as of January 1, 2019. Accounting for finance leases remained substantially unchanged and continues to be reported within Property and equipment, net and Long-term debt, with the current portion of the debt reported within Current portion of debt, in our consolidated balance sheets. There was no cumulative effect of applying the new standard and accordingly there was no adjustment to our retained earnings upon adoption. The comparative information presented has not been restated and continues to be reported under the accounting standards in effect for those periods. For further information on leases, refer to Note 9. Leases. This guidance did not have a material impact to our consolidated statements of comprehensive income (loss), consolidated statements of cash flows and our debt-covenants calculations under our current agreements. Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standard Update ("ASU") 2016-13, Financial Instruments - Credit Losses (Topic 326); Measurement of Credit Losses on Financial Instruments. This ASU, along with subsequent ASUs issued to clarify certain of its provisions, introduces new guidance which makes substantive changes to the accounting model for financial assets subject to credit losses that are measured at amortized cost, as well as certain off-balance sheet credit exposures. The primary updates include the introduction of a new current expected credit loss (“CECL”) model that is based on expected rather than incurred losses. This ASU and the related amendments will be effective for our annual reporting period beginning January 1, 2020. We are currently evaluating the impact of the adoption of this guidance to our consolidated financial statements.
Reclassifications	Reclassifications For the nine months ended September 30, 2019, we separately presented Amortization of commercial paper notes discount in our consolidated statements of cash flows. As a result, the prior year amortization amount was reclassified within Operating Activities to conform to the current year presentation.