Loans Payable, Long-Term Debt and Other Commitments

Loans payable at December 31, 2017 included $3.0 billion of notes due in 2018 and $73 million of long-dated notes that are subject to repayment at the option of the holder. Loans payable at December 31, 2016 included $300 million of notes due in 2017, $267 million of long-dated notes that are subject to repayment at the option of the holders. The weighted-average interest rate of commercial paper borrowings was 0.85% and 0.40% for the years ended December 31, 2017 and 2016, respectively.

Long-term debt at December 31 consisted of:



	2017		2016
2.75% notes due 2025	$	2,488	$	2,487
3.70% notes due 2045	1,973		1,972
2.80% notes due 2023	1,744		1,743
5.00% notes due 2019	1,260		1,273
4.15% notes due 2043	1,237		1,236
1.85% notes due 2020	1,232		1,238
2.35% notes due 2022	1,220		1,228
1.125% euro-denominated notes due 2021	1,185		1,035
1.875% euro-denominated notes due 2026	1,178		1,028
3.875% notes due 2021	1,140		1,152
2.40% notes due 2022	993		1,003
6.50% notes due 2033	729		806
Floating-rate notes due 2020	699		698
0.50% euro-denominated notes due 2024	591		516
1.375% euro-denominated notes due 2036	587		512
2.50% euro-denominated notes due 2034	585		511
3.60% notes due 2042	489		489
6.55% notes due 2037	415		594
5.75% notes due 2036	338		369
5.95% debentures due 2028	306		355
5.85% notes due 2039	270		415
6.40% debentures due 2028	250		325
6.30% debentures due 2026	135		152
Floating-rate borrowing due 2018	—		999
1.10% notes due 2018	—		999
1.30% notes due 2018	—		985
Other	309		154
	$	21,353	$	24,274

Other (as presented in the table above) includes $300 million and $147 million at December 31, 2017 and 2016, respectively, of borrowings at variable rates that resulted in effective interest rates of 1.42% and 0.89% for 2017 and 2016, respectively.

With the exception of the 6.30% debentures due 2026, the notes listed in the table above are redeemable in whole or in part, at Merck’s option at any time, at varying redemption prices.

In November 2017, the Company launched tender offers for certain outstanding notes and debentures. The Company paid $810 million in aggregate consideration (applicable purchase price together with accrued interest) to redeem $585 million principal amount of debt that was validly tendered in connection with the tender offers and recognized a loss on extinguishment of debt of $191 million in 2017.

Effective as of November 3, 2009, the Company executed a full and unconditional guarantee of the then existing debt of its subsidiary Merck Sharp & Dohme Corp. (MSD) and MSD executed a full and unconditional guarantee of the then existing debt of the Company (excluding commercial paper), including for payments of principal and interest. These guarantees do not extend to debt issued subsequent to that date.

Certain of the Company’s borrowings require that Merck comply with financial covenants including a requirement that the Total Debt to Capitalization Ratio (as defined in the applicable agreements) not exceed 60%. At December 31, 2017, the Company was in compliance with these covenants.

The aggregate maturities of long-term debt for each of the next five years are as follows: 2018, $3.0 billion; 2019, $1.3 billion; 2020, $1.9 billion; 2021, $2.3 billion; 2022, $2.2 billion.

The Company has a $6.0 billion, five-year credit facility that matures in June 2022. The facility provides backup liquidity for the Company’s commercial paper borrowing facility and is to be used for general corporate purposes. The Company has not drawn funding from this facility.

Rental expense under operating leases, net of sublease income, was $327 million in 2017, $292 million in 2016 and $303 million in 2015. The minimum aggregate rental commitments under noncancellable leases are as follows: 2018, $255 million; 2019, $175 million; 2020, $126 million; 2021, $90 million; 2022, $68 million and thereafter, $138 million. The Company has no significant capital leases.