Notes Payable and Long-Term Debt

As of June 30, 2018 and December 31, 2017, the Company had short-term and long-term debt outstanding as follows:



	June 30,		December 31,
(in millions)	2018		2017
Short-term debt
Short-term borrowings	$	67.7	$	68.8

Long-term debt
8.00% Senior notes due 10/01/19 ($134 million par value)	136.4		137.4
4.625% Senior notes due 09/15/20 ($250 million par value)	251.2		251.4
1.80% Senior notes due 11/7/22 (€500 million par value)	580.1		595.7
3.375% Senior notes due 03/15/25 ($500 million par value)	496.3		496.1
7.125% Senior notes due 02/15/29 ($121 million par value)	119.0		118.9
4.375% Senior notes due 03/15/45 ($500 million par value)	493.6		493.5
Term loan facilities and other	28.7		26.5
Total long-term debt	2,105.3		2,119.5
Less: current portion	2.8		15.8
Long-term debt, net of current portion	$	2,102.5	$	2,103.7

In July 2016, the Company terminated interest rate swaps which had the effect of converting $384.0 million of fixed rate notes to variable rates. The gain on the termination was recorded as an increase to the notes and is being amortized as a reduction to interest expense over the remaining terms of the notes. The unamortized gain related to these swap terminations as of June 30, 2018 was $2.4 million and $0.6 million on the 4.625% and 8.00% notes, respectively. The unamortized gain related to these swap terminations as of December 31, 2017 was $2.9 million and $0.8 million on the 4.625% and 8.00% notes, respectively.

The Company terminated fixed to floating interest rate swaps in 2009. The gain on the termination was recorded as an increase to the notes and is being amortized as a reduction to interest expense over the remaining term of the notes. The unamortized gain related to this swap termination at June 30, 2018 and December 31, 2017 was $1.9 million and $2.7 million, respectively, on the 8.00% notes.

The weighted average interest rate on short-term borrowings outstanding as of June 30, 2018 and December 31, 2017 was 3.2% and 3.1%, respectively. The weighted average interest rate on all borrowings outstanding, including the effects of outstanding swaps, as of June 30, 2018 and December 31, 2017 was 3.4% and 3.8%, respectively.

The Company has a $1.2 billion multi-currency revolving credit facility, which includes a feature that allows the Company's borrowings to be increased to $1.5 billion. The facility provides for borrowings through June 29, 2022. The Company has one key financial covenant as part of the credit agreement which is a debt to EBITDA ("Earnings Before Interest, Taxes, Depreciation and Amortization") ratio. The Company was in compliance with the financial covenant at June 30, 2018. At June 30, 2018 and December 31, 2017, the Company had no outstanding borrowings under this facility.

The Company's commercial paper program allows the Company to issue short-term, unsecured commercial paper notes up to a maximum aggregate principal amount outstanding of $1.2 billion. Under this program, the Company may issue notes from time to time and will use the proceeds for general corporate purposes. The Company had no outstanding borrowings under this program as of June 30, 2018 and December 31, 2017.

The total current combined borrowing capacity under the multi-currency revolving credit facility and commercial paper program cannot exceed $1.2 billion.

As of June 30, 2018 and December 31, 2017, the estimated fair values of the Company’s senior unsecured notes totaled $2,153.8 million and $2,209.1 million, respectively. The estimated fair values were $77.2 million and $116.1 million higher than their carrying value at June 30, 2018 and December 31, 2017, respectively. Fair market values of the senior unsecured notes are developed using observable values for similar debt instruments, which are considered Level 2 inputs as defined by ASC Topic 820. The carrying values of the Company's multi-currency revolving credit facility and commercial paper program approximates fair value. The fair value estimates do not necessarily reflect the values the Company could realize in the current markets.

The Company had outstanding letters of credit of $29.3 million and $31.4 million at June 30, 2018 and December 31, 2017, respectively. The letters of credit typically act as guarantees of payment to certain third parties in accordance with specified terms and conditions.