Note 8 — Debt

Long-term debt consisted of the following at September 30, 2014 and December 31, 2013:


	September 30, 2014		December 31, 2013
Senior unsecured notes:
7.375% Senior Notes due March 2014	$	—	$	249,964
3.45% Senior Notes due August 2015		350,000		350,000
3.05% Senior Notes due March 2016		299,978		299,967
2.50% Senior Notes due March 2017		299,912		299,886
7.50% Senior Notes due March 2019		201,695		201,695
4.90% Senior Notes due August 2020		499,118		499,022
4.625% Senior Notes due March 2021		399,614		399,576
3.95% Senior Notes due March 2022		399,242		399,178
6.20% Senior Notes due August 2040		399,894		399,893
6.05% Senior Notes due March 2041		397,672		397,646
5.25% Senior Notes due March 2042		498,303		498,283

Total senior unsecured notes		3,745,428		3,995,110

Commercial paper program		991,653		1,561,141

Total long-term debt	$	4,737,081	$	5,556,251

Credit Facilities and Commercial Paper Program

We currently have three credit facilities with an aggregate maximum available capacity of $2.9 billion (together, the “Credit Facilities”). In August 2014, we extended the maturity date of our $600 million senior unsecured 364-day revolving credit facility for a six-month period to February 2015. In addition, we continue to maintain a $1.5 billion credit facility that matures in 2017 and an $800 million credit facility that matures in 2016. In February 2015, availability under the $800 million credit facility will be reduced by $36 million.

We have a commercial paper program, which allows us to issue up to $2.7 billion in unsecured commercial paper notes. Amounts issued under the commercial paper program are supported by the unused capacity under our Credit Facilities and, therefore, are classified as long-term on our Consolidated Balance Sheet. The outstanding amounts of commercial paper reduce availability under our Credit Facilities.

The Credit Facilities provide us with the ability to issue up to $375 million in letters of credit in the aggregate. The issuance of letters of credit under the Credit Facilities reduces the amount available for borrowing. At September 30, 2014, we had no letters of credit issued under the Credit Facilities.

Senior Unsecured Notes

In March 2014, we repaid our $250 million 7.375% Senior Notes using issuances under our commercial paper program.

Our $350 million 3.45% Senior Notes mature during the third quarter of 2015. We anticipate using availability under our Credit Facilities or commercial paper issuances to repay the outstanding balance; therefore, we continue to report the balance as long-term at September 30, 2014.

Covenants

The Credit Facilities are guaranteed by our indirect wholly-owned subsidiaries, Noble Holding International Limited (“NHIL”) and Noble Holding Corporation (“NHC”). The covenants and events of default under the Credit Facilities are substantially similar, and each facility contains a covenant that limits our ratio of debt to total tangible capitalization, as defined in the Credit Facilities, to 0.60. At September 30, 2014, our ratio of debt to total tangible capitalization was approximately 0.37. We were in compliance with all covenants under the Credit Facilities as of September 30, 2014.

In addition to the covenants from the Credit Facilities noted above, the indentures governing our outstanding senior unsecured notes contain covenants that place restrictions on certain merger and consolidation transactions, unless we are the surviving entity or the other party assumes the obligations under the indenture, and on the ability to sell or transfer all or substantially all of our assets. In addition, there are restrictions on incurring or assuming certain liens and sale and lease-back transactions. At September 30, 2014, we were in compliance with all of our debt covenants. We continually monitor compliance with the covenants under our notes and expect to remain in compliance during the remainder of 2014.

Fair Value of Debt

Fair value represents the amount at which an instrument could be exchanged in a current transaction between willing parties. The estimated fair value of our senior notes was based on the quoted market prices for similar issues or on the current rates offered to us for debt of similar remaining maturities (Level 2 measurement). All remaining fair value disclosures are presented in Note 13.

The following table presents the estimated fair value of our long-term debt as of September 30, 2014 and December 31, 2013, respectively:


	September 30, 2014				December 31, 2013
	Carrying Value		Estimated Fair Value		Carrying Value		Estimated Fair Value
Senior unsecured notes:
7.375% Senior Notes due March 2014	$	—	$	—	$	249,964	$	253,634
3.45% Senior Notes due August 2015		350,000		357,087		350,000		363,019
3.05% Senior Notes due March 2016		299,978		306,752		299,967		309,878
2.50% Senior Notes due March 2017		299,912		303,855		299,886		302,891
7.50% Senior Notes due March 2019		201,695		232,264		201,695		232,839
4.90% Senior Notes due August 2020		499,118		530,788		499,022		528,597
4.625% Senior Notes due March 2021		399,614		413,996		399,576		413,868
3.95% Senior Notes due March 2022		399,242		391,616		399,178		390,520
6.20% Senior Notes due August 2040		399,894		416,991		399,893		421,720
6.05% Senior Notes due March 2041		397,672		408,334		397,646		417,312
5.25% Senior Notes due March 2042		498,303		458,360		498,283		476,873

Total senior unsecured notes		3,745,428		3,820,043		3,995,110		4,111,151

Commercial paper program		991,653		991,653		1,561,141		1,561,141

Total long-term debt	$	4,737,081	$	4,811,696	$	5,556,251	$	5,672,292