Debt

Total debt at March 31, 2019 and December 31, 2018 consisted of the following:



	Interest rate	March 31, 2019		December 31, 2018
Notes due September 2020	3.875%	$	300,000	$	300,000
Notes due October 2021	3.875%	600,000		600,000
Notes due May 2022	4.375%	400,000		400,000
Notes due April 2023	4.95%	400,000		400,000
Notes due March 2024	4.625%	500,000		500,000
Notes due January 2037	5.25%	35,841		35,841
Notes due March 2043	6.7%	425,000		425,000
Term loans	Variable	617,500		630,000
Other debt		5,255		5,297
Principal amount		3,283,596		3,296,138
Less: unamortized costs, net		28,704		30,530
Total debt		3,254,892		3,265,608
Less: current portion long-term debt		207,231		199,535
Long-term debt		$	3,047,661	$	3,066,073

On April 17, 2019, Moody's lowered our corporate credit rating from Ba1 to Ba2. Interest rates on certain notes are subject to adjustment based on changes in our credit ratings. As a result, the coupon rate on $1.7 billion principal amount of our notes will increase by 0.25% effective at the next interest payment date for each security.

During the first quarter of 2019, we repaid $13 million of principal related to our term loans.