3. Debt

The following table summarizes the major components of debt as of each balance sheet date (in millions) and provides the maturities and interest rate ranges of each major category as of March 31, 2019:


	March 31,		December 31,
	2019		2018
$2.75 billion revolving credit facility (weighted average interest rate of 3.1% as of December 31, 2018)	$	—	$	11
Commercial paper program (weighted average interest rate of 2.8% as of March 31, 2019 and 2.9% as of December 31, 2018)		1,354		990
Senior notes, maturing through 2045, interest rates ranging from 2.4% to 7.75% (weighted average interest rate of 4.3% as of March 31, 2019 and December 31, 2018)		6,222		6,222
Tax-exempt bonds, maturing through 2048, fixed and variable interest rates ranging from 1.35% to 4.3% (weighted average interest rate of 2.4% as of March 31, 2019 and 2.35% as of December 31, 2018)		2,354		2,388
Financing leases and other, maturing through 2040, interest rates up to 9%		486		467
Debt issuance costs, discounts and other		(50)		(52)
		10,366		10,026
Current portion of long-term debt		1,043		432
	$	9,323	$	9,594

Debt Classification

As of March 31, 2019, we had $2.2 billion of debt maturing within the next 12 months, including (i) $1.4 billion of short-term borrowings under our commercial paper program; (ii) $680 million of tax-exempt bonds with term interest rate periods that expire within the next 12 months, which is prior to their scheduled maturities and (iii) $139 million of other debt with scheduled maturities within the next 12 months, including $72 million of tax-exempt bonds. Of the $1.4 billion of short-term borrowings outstanding under our commercial paper program as of March 31, 2019 that are supported by our long-term U.S. and Canadian revolving credit facility (“$2.75 billion revolving credit facility”), we have the intent and ability to refinance or maintain approximately $450 million of these borrowings on a long-term basis and we have classified these amounts as long-term debt. As of March 31, 2019, we have classified an additional $680 million of debt maturing in the next 12 months as long-term because we have the intent and ability to refinance these borrowings on a long-term basis as supported by the forecasted available capacity under our $2.75 billion revolving credit facility, as discussed below. The remaining $1.0 billion is classified as current obligations.

As of March 31, 2019, we also have $268 million of variable-rate tax-exempt bonds that are supported by letters of credit under our $2.75 billion revolving credit facility. The interest rates on our variable-rate tax-exempt bonds are generally reset on either a daily or weekly basis through a remarketing process. All recent tax-exempt bond remarketings have successfully placed Company bonds with investors at market-driven rates and we currently expect future remarketings to be successful. However, if the remarketing agent is unable to remarket our bonds, the remarketing agent can put the bonds to us. In the event of a failed remarketing, we have the availability under our $2.75 billion revolving credit facility to fund these bonds until they are remarketed successfully. Accordingly, we have also classified these borrowings as long-term in our Condensed Consolidated Balance Sheet as of March 31, 2019.

Access to and Utilization of Credit Facilities and Commercial Paper Program

$2.75 Billion Revolving Credit Facility — Our $2.75 billion revolving credit facility provides us with credit capacity to be used for either cash borrowings or to support letters of credit or commercial paper. The rates we pay for outstanding U.S. or Canadian loans are generally based on LIBOR or CDOR, respectively, plus a spread depending on the Company’s debt rating assigned by Moody’s Investors Service and Standard and Poor’s. As of March 31, 2019, we had no borrowings outstanding under this facility. We had $572 million of letters of credit issued and $1.4 billion of outstanding borrowings under our commercial paper program, both supported by this facility, leaving unused and available credit capacity of $824 million as of March 31, 2019. WM Holdings, a wholly-owned subsidiary of WM, guarantees all of the obligations under the $2.75 billion revolving credit facility.

Commercial Paper Program — We have a commercial paper program that enables us to borrow funds for up to 397 days at competitive interest rates. The rates we pay for outstanding borrowings are based on the term of the notes. The commercial paper program is fully supported by our $2.75 billion revolving credit facility. As of March 31, 2019, we had $1.4 billion of outstanding borrowings under our commercial paper program.

Other Letter of Credit Facilities — As of March 31, 2019, we utilized $542 million of other letter of credit facilities, which are both committed and uncommitted, with terms maturing through December 2020.

Debt Borrowings and Repayments

$2.75 Billion Revolving Credit Facility — During the three months ended March 31, 2019, we repaid C$15 million, or $11 million, of Canadian borrowings under our $2.75 billion revolving credit facility with available cash.

Commercial Paper Program — During the three months ended March 31, 2019, we had net cash borrowings of $357 million (net of the related discount on issuance). The proceeds from these borrowings were primarily used to support our acquisition of Petro Waste Environmental LP (“Petro Waste”), which is discussed further in Note 9, and for general corporate purposes.

Tax-Exempt Bonds — During the three months ended March 31, 2019, we repaid $34 million of our tax-exempt bonds with available cash.

Financing Leases and Other — The increase during the three months ended March 31, 2019, is primarily related to $30 million of non-cash financing arrangements, partially offset by $11 million of net cash repayments of debt at maturity.