7. Debt:

Long-term debt consists of first mortgage notes payable to the United States of America acting through the Federal Financing Bank (FFB) and guaranteed by the Rural Utilities Service or the U.S. Department of Energy, first mortgage bonds payable (FMBs), first mortgage notes issued in conjunction with the sale by public authorities of pollution control revenue bonds (PCBs) and first mortgage notes payable to CoBank and CFC. Substantially all of our owned tangible and certain of our intangible assets are pledged under our first mortgage indenture as collateral for the Federal Financing Bank notes, the first mortgage bonds, the first mortgage notes issued in conjunction with the sale of pollution control revenue bonds, and the CoBank and CFC first mortgage notes.

Maturities for long-term debt and capital lease obligations through 2020 are as follows:


			(dollars in thousands)
			2016		2017		2018		2019		2020

FFB		$	145,846	$	143,110	$	148,210	$	153,233	$	156,998
FMBs			1,010		1,010		1,010		351,010		1,010
PCBs(1)			37,352		37,352		37,352		–		181,075
CFC			891		937		984		1,035		391
CoBank			786		885		996		719		–

			185,885		183,294		188,552		505,997		339,474
Capital Leases			3,955		4,404		4,905		5,462		6,082

Total		$	189,840	$	187,698	$	193,457	$	511,459	$	345,556


(1)	In addition to regularly scheduled principal payments on the bonds, this includes amounts that would be due if the credit support facilities for the Series 2009 and Series 2010 pollution control bonds were drawn upon and became payable in accordance with their terms, such as would occur if the credit facility providing the support was not renewed or extended at its expiration date. These amounts equal $37 million in each of the years 2016, 2017 and 2018 and $134 million in 2020. We anticipate extending these credit facilities before their expiration. The nominal maturities of the Series 2009 and Series 2010 pollution control bonds range from 2030 through 2038.

The weighted average interest rate on our long-term debt at December 31, 2015 and 2014 was 4.45% and 4.55%, respectively.

Long-term debt principal and the associated unamortized debt issuance costs and debt discounts at December 31, 2015 and December 31, 2014 are as follows:


	2015				2014
		Principal		Unamortized Debt Issuance Costs and Debt Discounts		Principal		Unamortized Debt Issuance Costs and Debt Discounts

		(dollars in thousands)
FFB	$	3,777,540	$	56,851	$	3,456,953	$	58,417
FMBs		2,809,093		32,002		2,810,103		33,782
PCBs		980,770		9,135		980,770		9,740
CFC		4,238		–		5,085		–
CoBank		3,386		–		4,084		–

	$	7,575,027	$	97,988	$	7,256,995	$	101,939

We use the effective interest rate method to amortize debt issuance costs and debt discounts as well as the straight-line method when the results approximate those of the effective interest rate method. Unamortized debt issuance costs and debt discounts are being amortized to expense over the life of the respective debt issues.


a)	Department of Energy Loan Guarantee:

Pursuant to the loan guarantee program established under Title XVII of the Energy Policy Act of 2005 (the "Title XVII Loan Guarantee Program"), we and the U.S. Department of Energy, acting by and through the Secretary of Energy, entered into a Loan Guarantee Agreement on February 20, 2014 pursuant to which the Department of Energy agreed to guarantee our obligations under the Note Purchase Agreement dated as of February 20, 2014 (the "Note Purchase Agreement"), among us, the Federal Financing Bank and the Department of Energy and two future advance promissory notes, each dated February 20, 2014, made by us to the Federal Financing Bank (the "Federal Financing Bank Notes" and together with the Note Purchase Agreement, the "FFB Credit Facility Documents"). The FFB Credit Facility Documents provide for a multi-advance term loan facility (the "Facility"), under which we may make long-term loan borrowings through the Federal Financing Bank.

Proceeds of advances made under the Facility will be used to reimburse us for a portion of certain costs of construction relating to Vogtle Units No. 3 and No. 4 that are eligible for financing under the Title XVII Loan Guarantee Program. Aggregate borrowings under the Facility may not exceed $3,057,069,461 of which $335,471,604 is designated for capitalized interest.

Advances may be requested under the Facility on a quarterly basis through December 31, 2020. During 2015, we received advances under the Facility totaling $270,000,000. At December 31, 2015, aggregate DOE-guaranteed borrowings totaled $1,180,628,000, including capitalized interest.


b)	Rural Utilities Service Guaranteed Loans:

During 2015, we received advances on Rural Utilities Service-guaranteed Federal Financing Bank loans totaling $153,637,000 for long-term financing of general and environmental improvements at existing plants.

In January 2016, we received an additional $7,998,000 in advances on Rural Utilities Service-guaranteed Federal Financing Bank loans for long-term financing of general and environmental improvements at existing plants.


c)	Credit Facilities:

On March 23, 2015, we entered into a 5-year $1,210,000,000 credit agreement with a syndicate of thirteen lenders, led by the National Rural Utilities Cooperative Finance Corporation as administrative agent.

As of December 31, 2015, we had a total of $1,610,000,000 of committed credit arrangements comprised of four separate facilities with maturity dates that range from November 2016 to March 2020. These credit facilities are for general working capital purposes, issuing letters of credit and backing up outstanding commercial paper. Under our unsecured committed lines of credit that we had in place at December 31, 2015, we had the ability to issue letters of credit totaling $760,000,000 in the aggregate, of which $509,000,000 remained available. At December 31, 2015, we had 1) $251,000,000 under these lines of credit in the form of issued letters of credit supporting variable rate demand bonds and collateral postings to third parties, and 2) $261,000,000 dedicated under one of these lines of credit to support a like amount of commercial paper that was outstanding.

The weighted average interest rate on short-term borrowings at December 31, 2015 and December 31, 2014 was 0.43% and 0.28%, respectively.