Debt

6 Months Ended

Jun. 30, 2019

Long-term debt at December 31, 2018 and June 30, 2019 was as follows (in thousands):



	December 31, 2018			June 30, 2019
Commercial paper	$	—		$	197,000
6.55% Notes due 2019	550,000			—
4.25% Notes due 2021	550,000			550,000
3.20% Notes due 2025	250,000			250,000
5.00% Notes due 2026	650,000			650,000
6.40% Notes due 2037	250,000			250,000
4.20% Notes due 2042	250,000			250,000
5.15% Notes due 2043	550,000			550,000
4.20% Notes due 2045	250,000			250,000
4.25% Notes due 2046	500,000			500,000
4.20% Notes due 2047	500,000			500,000
4.85% Notes due 2049	—			500,000
Face value of long-term debt	4,300,000			4,447,000
Unamortized debt issuance costs⁽¹⁾	(27,070		)	(31,195		)
Net unamortized debt discount⁽¹⁾	(2,927		)	(8,012		)
Net unamortized amount of gains from historical fair value hedges⁽¹⁾	866			—
Long-term debt, net, including current portion	4,270,869			4,407,793
Less: Current portion of long-term debt, net	59,489			—
Long-term debt, net	$	4,211,380		$	4,407,793


(1)	Debt issuance costs, note discounts and premiums and realized gains and losses of historical fair value hedges are being amortized or accreted to the applicable notes over the respective lives of those notes.

All of the instruments detailed in the table above are senior indebtedness.

2019 Debt Issuance

On January 18, 2019, we issued $500.0 million of 4.85% senior notes due 2049 in an underwritten public

offering. The notes were issued at 99.371% of par. Net proceeds from this offering were approximately $491.5 million after underwriting discounts and offering expenses. The net proceeds from this offering along with cash on hand were used to early redeem our $550.0 million of 6.55% senior notes due 2019 on February 11, 2019. In connection with this offering, we recognized $8.3 million of debt prepayment costs that were recorded as interest expense in our consolidated statements of income.

Other Debt

Revolving Credit Facilities. At June 30, 2019, the total borrowing capacity under our revolving credit facility maturing in May 2024 was $1.0 billion. Any borrowings outstanding under this facility are classified as long-term debt on our consolidated balance sheets. Borrowings under this facility are unsecured and bear interest at LIBOR plus a spread ranging from 0.875% to 1.500% based on our credit ratings. Additionally, an unused commitment fee is assessed at a rate between 0.075% and 0.200% depending on our credit ratings. The unused commitment fee was 0.125% at June 30, 2019. Borrowings under this facility may be used for general partnership purposes, including capital expenditures. As of December 31, 2018 and June 30, 2019, there were no borrowings outstanding under this facility, with $6.8 million and $3.5 million, respectively, obligated for letters of credit. Amounts obligated for letters

of credit are not reflected as debt on our consolidated balance sheets, but decrease our borrowing capacity under this facility.

In second quarter 2019, we entered into a $500.0 million 364-day revolving credit facility, which matures in May 2020. Borrowings under this facility are unsecured and generally bear interest at LIBOR plus a spread ranging from 1.000% to 1.250% based on our credit ratings. Additionally, an unused commitment fee is assessed at a rate between 0.075% and 0.125%. The unused commitment fee was 0.100% at June 30, 2019. Borrowings under this facility may be used for general purposes, including capital expenditures. As of June 30, 2019, there were no borrowings outstanding under this facility.

Commercial Paper Program. We have a commercial paper program under which we may issue commercial paper notes in an amount up to the available capacity under our $1.0 billion revolving credit facility. The maturities of the commercial paper notes vary, but may not exceed 397 days from the date of issuance. Because the commercial paper we can issue is limited to amounts available under our revolving credit facility, amounts outstanding under the program are classified as long-term debt. The commercial paper notes are sold under customary terms in the commercial paper market and are issued at a discount from par, or alternatively, are sold at par and bear varying interest rates on a fixed or floating basis. The weighted-average interest rate for commercial paper borrowings based on the number of days outstanding was 2.3% for the year ended December 31, 2018 and 2.7% for the six months ended June 30, 2019.