Long-Term Debt	6 Months Ended
Jun. 30, 2018
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt In June 2018, we entered into a credit agreement for the financing of a portion of the purchase price payable for the Silversea Cruises acquisition and to pay related fees and expenses. This agreement makes available to us an unsecured U.S. dollar denominated term loan with a maximum aggregate principal amount of $700 million. On July 31, 2018, we closed on the Silversea Cruises acquisition and subsequently drew in full on this credit agreement. The loan is due in July 2019 and we are required to prepay the loan with the proceeds of certain debt issuances prior to maturity. Interest on the loan will accrue at a floating rate based on LIBOR plus a margin that varies with our credit rating and which is currently 1.00%. In June 2018, we established a commercial paper program pursuant to which we may issue short-term unsecured notes from time to time in an aggregate amount of up to $1.2 billion. The commercial paper issued will be backstopped by our revolving credit facilities. As of June 30, 2018, we had not issued any notes under this program and as of July 31, 2018, we had $415.0 million of commercial paper notes outstanding. In March 2018, we took delivery of Symphony of the Seas. We had previously entered into a financing arrangement for the United States dollar financing of this ship in January 2015. Through the financing arrangement, we had the right, but not the obligation, to satisfy the obligations to be incurred upon delivery and acceptance of the vessel under the shipbuilding contract by assuming through a novation agreement, at delivery and acceptance, the debt indirectly incurred by the shipbuilder during the construction of the ship. We borrowed a total of $1.2 billion under our previously committed unsecured term loan, which includes the execution of the novation to satisfy a portion of our final obligation under our shipbuilding agreement. The loan amortizes semi-annually over 12 years and bears interest at a fixed rate of 3.82%. In our consolidated statement of cash flows for the six months ended June 30, 2018, the acceptance of the ship and satisfaction of our obligation under the shipbuilding contract was classified as an outflow and constructive disbursement within Investing Activities while the amounts novated and effectively advanced from our lender under our previously committed unsecured term loan were classified as an inflow and constructive receipt within Financing Activities. In March 2018, we entered into and drew in full on a credit agreement in the amount of $130.0 million due February 2023. The loan accrues interest at a floating rate of LIBOR plus an applicable margin. The applicable margin varies with our debt rating and was 1.195% as of June 30, 2018. Amounts from the issuance of this loan were used for capital expenditures.

Long-Term Debt

In June 2018, we entered into a credit agreement for the financing of a portion of the purchase price payable for the Silversea Cruises acquisition and to pay related fees and expenses. This agreement makes available to us an unsecured U.S. dollar denominated term loan with a maximum aggregate principal amount of $700 million. On July 31, 2018, we closed on the Silversea Cruises acquisition and subsequently drew in full on this credit agreement. The loan is due in July 2019 and we are required to prepay the loan with the proceeds of certain debt issuances prior to maturity. Interest on the loan will accrue at a floating rate based on LIBOR plus a margin that varies with our credit rating and which is currently 1.00%.

In June 2018, we established a commercial paper program pursuant to which we may issue short-term unsecured notes from time to time in an aggregate amount of up to $1.2 billion. The commercial paper issued will be backstopped by our revolving credit facilities. As of June 30, 2018, we had not issued any notes under this program and as of July 31, 2018, we had $415.0 million of commercial paper notes outstanding.

In March 2018, we took delivery of Symphony of the Seas. We had previously entered into a financing arrangement for the United States dollar financing of this ship in January 2015. Through the financing arrangement, we had the right, but not the obligation, to satisfy the obligations to be incurred upon delivery and acceptance of the vessel under the shipbuilding contract by assuming through a novation agreement, at delivery and acceptance, the debt indirectly incurred by the shipbuilder during the construction of the ship. We borrowed a total of $1.2 billion under our previously committed unsecured term loan, which includes the execution of the novation to satisfy a portion of our final obligation under our shipbuilding agreement. The loan amortizes semi-annually over 12 years and bears interest at a fixed rate of 3.82%. In our consolidated statement of cash flows for the six months ended June 30, 2018, the acceptance of the ship and satisfaction of our obligation under the shipbuilding contract was classified as an outflow and constructive disbursement within Investing Activities while the amounts novated and effectively advanced from our lender under our previously committed unsecured term loan were classified as an inflow and constructive receipt within Financing Activities.

In March 2018, we entered into and drew in full on a credit agreement in the amount of $130.0 million due February 2023. The loan accrues interest at a floating rate of LIBOR plus an applicable margin. The applicable margin varies with our debt rating and was 1.195% as of June 30, 2018. Amounts from the issuance of this loan were used for capital expenditures.