Debt

Short-Term Borrowings and Current Portion of Long-Term Debt: The carrying value of short-term borrowings and current portion of long-term debt outstanding at December 31, 2015 and December 31, 2014 includes:



	2015		2014
Commercial paper	$	—	$	99.6
2.450% senior notes due 2015	—		506.3
Total	$	—	$	605.9

Long-Term Debt: We have an aggregate $14.250 billion principal amount of senior notes outstanding at varying maturity dates and interest rates. The carrying values of the long-term portion of these senior notes at December 31, 2015 and 2014 are summarized below:



	2015		2014
1.900% senior notes due 2017	$	501.2	$	501.0
2.125% senior notes due 2018	999.9		—
2.300% senior notes due 2018	401.7		401.2
2.250% senior notes due 2019	505.1		502.5
2.875% senior notes due 2020	1,497.5		—
3.950% senior notes due 2020	507.1		502.8
3.250% senior notes due 2022	1,016.1		1,010.2
3.550% senior notes due 2022	997.4		—
4.000% senior notes due 2023	710.3		708.5
3.625% senior notes due 2024	1,001.7		996.8
3.875% senior notes due 2025	2,475.6		—
5.700% senior notes due 2040	249.6		249.5
5.250% senior notes due 2043	396.7		396.7
4.625% senior notes due 2044	996.6		996.5
5.000% senior notes due 2045	1,993.9		—
Total long-term debt	$	14,250.4	$	6,265.7

At December 31, 2015, the fair value of our outstanding Senior Notes was $14.299 billion and represented a Level 1 measurement within the fair value measurement hierarchy.

In August 2015, we issued an additional $8.000 billion principal amount of senior notes consisting of $1.000 billion aggregate principal amount of 2.125% Senior Notes due 2018 (the 2018 notes), $1.500 billion aggregate principal amount of 2.875% Senior Notes due 2020 (the 2020 notes), $1.000 billion aggregate principal amount of 3.550% Senior Notes due 2022 (the 2022 notes), $2.500 billion aggregate principal amount of 3.875% Senior Notes due 2025 (the 2025 notes) and $2.000 billion aggregate principal amount of 5.000% Senior Notes due 2045 (the 2045 notes and together with the 2018 notes, the 2020 notes, the 2022 notes, and the 2025 notes, referred to herein as the “2015 issued notes”).

The 2015 issued notes were issued at 99.994%, 99.819%, 99.729%, 99.034%, and 99.691% of par, respectively, and the discount is being amortized as additional interest expense over the period from issuance through maturity. Offering costs of approximately $50.0 million have been recorded as debt issuance costs on our Consolidated Balance Sheets and are being amortized as additional interest expense using the effective interest rate method over the period from issuance through maturity. Interest on the 2015 issued notes is payable semi-annually in arrears on February 15 and August 15 each year beginning February 15, 2016 and the principal on each 2015 issued note is due in full at their respective maturity dates. The 2015 issued notes may be redeemed at our option, in whole or in part; the 2018 notes, the 2020 notes, and the 2022 notes may be redeemed at any time, the 2025 notes and 2045 notes may be redeemed at three months and six months prior to the maturity dates, respectively.

Early redemption would be at a redemption price equaling accrued and unpaid interest plus the greater of 100% of the principal amount of the 2015 issued notes to be redeemed or the sum of the present values of the remaining scheduled payments of interest and principal discounted to the date of redemption on a semi-annual basis plus 20 basis points in the case of the 2018 notes, 20 basis points in the case of the 2020 notes, 25 basis points in the case of the 2022 notes, 30 basis points in the case of the 2025 notes, and 35 basis points in the case of the 2045 notes. If we experience a change of control accompanied by a downgrade of the debt to below investment grade, we will be required to offer to repurchase the 2015 issued notes at a purchase price equal to 101% of their principal amount plus accrued and unpaid interest. We are subject to covenants which limit our ability to pledge properties as security under borrowing arrangements and limit our ability to perform sale and leaseback transactions involving our property.

In 2015, the 2.45% senior notes with a principal amount of $500.0 million matured and were repaid. We also assumed $13.9 million of debt obligations as part of the acquisition of Quanticel in 2015 that were repaid in 2015.

From time to time, we have used treasury rate locks and forward starting interest rate swap contracts to hedge against changes in interest rates in anticipation of issuing fixed-rate notes. As of December 31, 2015, a balance of $68.1 million in losses remained in accumulated OCI related to settlements of these derivative instruments and will be recognized as interest expense over the life of the notes.

At December 31, 2015, we were party to pay-floating, receive-fixed interest rate swap contracts designated as fair value hedges

of fixed-rate notes as described in Note 5. Our swap contracts outstanding at December 31, 2015 effectively convert the hedged portion of our fixed-rate notes to floating rates. From time to time we terminate the hedging relationship on certain of our swap contracts by settling the contracts or by entering into offsetting contracts. Any net proceeds received or paid in these settlements are accounted for as a reduction or increase of current and future interest expense associated with the previously hedged notes. As of December 31, 2015, we had a balance of $33.1 million of unamortized gains recorded as a component of our debt as a result of past swap contract settlements, including $6.0 million related to the settlement of swap contracts during 2015.

Commercial Paper: The carrying value of Commercial Paper as of December 31, 2015 and 2014 was $0.0 million and $99.6 million, respectively, and approximated its fair value. As of December 31, 2015, we had available capacity to issue up to $1.750 billion of Commercial Paper and there were no borrowings under the Program.

Senior Unsecured Credit Facility: We maintain a senior unsecured revolving credit facility (Credit Facility) that provides revolving credit in the aggregate amount of $1.750 billion, which was increased from $1.500 billion in April 2015. Also in April 2015, the term of the Credit Facility was extended from April 18, 2018 to April 17, 2020. Subject to certain conditions, we have the right to increase the amount of the Credit Facility (but in no event more than one time per annum) up to a maximum aggregate amount of $2.000 billion. Amounts may be borrowed in U.S. dollars for general corporate purposes. The Credit Facility currently serves as backup liquidity for our Commercial Paper borrowings. At December 31, 2015 and 2014, there was no outstanding borrowing against the Credit Facility.

The Credit Facility contains affirmative and negative covenants including certain customary financial covenants. We were in compliance with all financial covenants as of December 31, 2015.