Debt

MPLX’s outstanding borrowings at December 31, 2018 and 2017 consisted of the following:



	December 31,
(In millions)	2018			2017
MPLX LP:
Bank revolving credit facility due 2022	$	—		$	505
5.500% senior notes due February 2023	—			710
3.375% senior notes due March 2023	500			—
4.500% senior notes due July 2023	989			989
4.875% senior notes due December 2024	1,149			1,149
4.000% senior notes due February 2025	500			500
4.875% senior notes due June 2025	1,189			1,189
4.125% senior notes due March 2027	1,250			1,250
4.000% senior notes due March 2028	1,250			—
4.800% senior notes due February 2029	750			—
4.500% senior notes due April 2038	1,750			—
5.200% senior notes due March 2047	1,000			1,000
4.700% senior notes due April 2048	1,500			—
5.500% senior notes due February 2049	1,500			—
4.900% senior notes due April 2058	500			—
Consolidated subsidiaries:
MarkWest - 4.500% - 4.875% senior notes, due 2023-2025	23			63
Capital lease obligations due 2020	6			7
Total	13,856			7,362
Unamortized debt issuance costs	(97		)	(27		)
Unamortized discount	(366		)	(389		)
Amounts due within one year	(1		)	(1		)
Total long-term debt due after one year	$	13,392		$	6,945

The following table shows five years of scheduled debt payments.



(In millions)
2019	$	1
2020	5
2021	—
2022	—
2023	$	1,500

Credit Agreements

On July 21, 2017, MPLX entered into a syndicated credit agreement to replace its previously outstanding $2 billion five-year bank revolving credit facility and $250 million term loan with a $2.25 billion five-year bank revolving credit facility that expires in July 2022 (the “MPLX Credit Agreement”). The financial covenants and the interest rate terms contained in the new credit agreement are substantially the same as those contained in the previous bank revolving credit facility. On July 19, 2017, MPLX prepaid the previously outstanding principal of the term loan with cash on hand. The borrowings under the term loan facility bore interest between January 1, 2017 and July 19, 2017 at an average interest rate of 2.407 percent.

The MPLX Credit Agreement includes letter of credit issuing capacity of up to $222 million and swingline capacity of up to $100 million. The borrowing capacity under the MPLX Credit Agreement may be increased by up to an additional $500 million, subject to certain conditions, including the consent of lenders whose commitments would increase. In addition, the maturity date may be extended, for up to two additional one-year periods, subject to, among other conditions, the approval of lenders holding the majority of the commitments then outstanding, provided that the commitments of any non-consenting lenders will terminate on the then-effective maturity date. Borrowings under the MPLX Credit Agreement bear interest at either the Adjusted LIBOR or the Alternate Base Rate (as defined in the MPLX Credit Agreement), at our election, plus a specified margin. MPLX is charged various fees and expenses in connection with the agreement, including administrative agent fees, commitment fees on the unused portion of the facility and fees with respect to issued and outstanding letters of credit. The applicable margins to the benchmark interest rates and certain fees fluctuate based on the credit ratings in effect from time to time on MPLX’s long-term debt.

The MPLX Credit Agreement contains certain representations and warranties, affirmative and restrictive covenants and events of default that MPLX considers to be usual and customary for an agreement of this type, including a financial covenant that requires MPLX to maintain a ratio of Consolidated Total Debt as of the end of each fiscal quarter to Consolidated EBITDA (both as defined in the MPLX Credit Agreement) for the prior four fiscal quarters of no greater than 5.0 to 1.0 (or 5.5 to 1.0 for up to two fiscal quarters following certain acquisitions). Consolidated EBITDA is subject to adjustments for certain acquisitions and dispositions completed and capital projects undertaken during the relevant period. Other covenants restrict MPLX and/or certain of its subsidiaries from incurring debt, creating liens on our assets and entering into transactions with affiliates. As of December 31, 2018, MPLX was in compliance with the covenants contained in the MPLX Credit Agreement.

During the year ended December 31, 2018, MPLX borrowed $1,410 million under the MPLX Credit Agreement, at a weighted average interest rate of 3.464 percent, and repaid $1,915 million of these borrowings. At December 31, 2018, MPLX had no outstanding borrowings and $3 million letters of credit outstanding under the new facility, resulting in total availability of $2.2 billion, or 99.9 percent of the borrowing capacity.

During 2017, MPLX had no borrowings under the previous bank revolving credit facility. During the year ended December 31, 2017, MPLX borrowed $670 million under the MPLX Credit Agreement, at a weighted average interest rate of 2.748 percent, and repaid $165 million of these borrowings. At December 31, 2017, MPLX had $505 million outstanding borrowings and $3 million letters of credit outstanding under this facility, resulting in total unused loan availability of $1.7 billion, or 77.4 percent of the borrowing capacity.

Senior Notes

Interest on each series of MPLX LP and MarkWest senior notes is payable semi-annually in arrears, according to the table below.



Senior Notes		Interest payable semi-annually in arrears
3.375% senior notes due 2023		March 15^th and September 15^th
4.500% senior notes due 2023		January 15^th and July 15^th
4.875% senior notes due 2024		June 1^st and December 1^st
4.000% senior notes due 2025		February 15^th and August 15^th
4.875% senior notes due 2025		June 1^st and December 1^st
4.125% senior notes due 2027		March 1^st and September 1^st
4.000% senior notes due 2028		March 15^th and September 15^th
4.800% senior notes due 2029		February 15^th and August 15^th
4.500% senior notes due 2038		April 15^th and October 15^th
5.200% senior notes due 2047		March 1^st and September 1^st
4.700% senior notes due 2048		April 15^th and October 15^th
5.500% senior notes due 2049		February 15^th and August 15^th
4.900% senior notes due 2058		April 15^th and October 15^th

On December 10, 2018, MPLX redeemed all of the $750 million 5.5 percent senior notes due February 15, 2023, $40 million of which was issued by the MarkWest subsidiary. These notes were redeemed at 101.833 percent of the principal amount, which resulted in a payment of $14 million related to the note premium and the immediate recognition of $46 million of unamortized debt issuance costs.

On November 15, 2018, MPLX issued $2.25 billion aggregate principal amount of senior notes in a public offering, consisting of $750 million aggregate principal amount of 4.8 percent unsecured senior notes due February 2029 and $1.5 billion aggregate principal amount of 5.5 percent unsecured senior notes due February 2049 (collectively, the “November 2018 New Senior Notes”). The November 2018 New Senior Notes were offered at a price to the public of 99.432 percent and 98.031 percent of par, respectively. The proceeds were used to repay outstanding borrowings under the MPLX Credit Agreement and the MPC Loan Agreement and to redeem the $750 million 5.5 percent senior notes due February 2023, as well as for general business purposes. Interest on each series of notes in the November 2018 New Senior Notes is payable semi-annually in arrears, commencing on February 15, 2019.

On February 8, 2018, MPLX issued $5.5 billion aggregate principal amount of senior notes in a public offering, consisting of $500 million aggregate principal amount of 3.375 percent unsecured senior notes due March 2023, $1.25 billion aggregate principal amount of 4.0 percent unsecured senior notes due March 2028, $1.75 billion aggregate principal amount of 4.5 percent unsecured senior notes due April 2038, $1.5 billion aggregate principal amount of 4.7 percent unsecured senior notes due April 2048, and $500 million aggregate principal amount of 4.9 percent unsecured senior notes due April 2058 (collectively, the “February 2018 New Senior Notes”). The February 2018 New Senior Notes were offered at a price to the public of 99.931 percent, 99.551 percent, 98.811 percent, 99.348 percent, and 99.289 percent of par, respectively. Also on February 8, 2018, $4.1 billion of the net proceeds from the offering were used to repay the 364-day term loan facility, which was drawn on February 1, 2018 to fund the cash portion of the dropdown consideration for Refining Logistics and Fuels Distribution. The remaining proceeds were used to repay outstanding borrowings under the MPLX Credit Agreement and the MPC Loan Agreement, as well as for general business purposes. Interest on each series of notes due in 2023 and 2028 is payable semi-annually in arrears, commencing on September 15, 2018. Interest on each series of notes due in 2038, 2048 and 2058 is payable semi-annually in arrears, commencing on October 15, 2018.

On February 10, 2017, MPLX completed a public offering of $1.25 billion aggregate principal amount of 4.125 percent unsecured senior notes due March 2027 (the “2027 Senior Notes”) and $1.0 billion aggregate principal amount of 5.200 percent unsecured senior notes due March 2047 (the “2047 Senior Notes”). The 2027 Senior Notes and the 2047 Senior Notes were offered at a price to the public of 99.834 percent and 99.304 percent of par, respectively. The net proceeds were used to fund the $1.5 billion cash portion of the consideration paid to MPC for the dropdown of assets on March 1, 2017, as well as for general business purposes.

SMR Transaction

On September 1, 2009, MarkWest completed the sale of the SMR (the “SMR Transaction”). At that time, MarkWest had begun constructing the SMR at its Javelina gas processing and fractionation complex in Corpus Christi, Texas. Under the terms of the agreement, MarkWest received proceeds of $73 million and the purchaser completed the construction of the SMR. MarkWest and the purchaser also executed a related product supply agreement under which MPLX will receive the entire product produced by the SMR through 2030 in exchange for processing fees and the reimbursement of certain other expenses. The processing fee payments began when the SMR commenced operations in March 2010. MarkWest was deemed to have continuing involvement with the SMR as a result of certain provisions in the related agreements. Therefore, the transaction is treated as a financing arrangement under GAAP. MPLX imputes interest on the SMR liability at 6.39 percent annually, its incremental borrowing rate at the time of the purchase accounting valuation. Each processing fee payment has multiple elements: reduction of principal of the SMR liability, interest expense associated with the SMR liability and facility expense related to the operation of the SMR. As part of purchase accounting, the SMR Transaction has been recorded at fair value. As of December 31, 2018 and 2017, the following amounts related to the SMR are included in the accompanying Consolidated Balance Sheets:



(In millions)	December 31, 2018		December 31, 2017
Assets
Property, plant and equipment, net	$	51	$	56
Liabilities
Accrued liabilities	5		5
Deferred credits and other liabilities	$	81	$	86