Changes in long-term debt, excluding current portion, (in millions) were as follows:



	For the Nine
	Months Ended
	September 30,
		2019
Balance as of beginning-of-year		$	5,839
Senior notes issued:
3.05% notes, due 2030			500
Early extinguishment of senior notes:
4.85% notes, due 2021			(4	)
6.15% notes, due 2036			(105	)
Reclassification of long-term debt to current maturities			(300	)
Unamortized debt issuance costs			(1	)
Unamortized adjustments from discontinued hedges			(4	)
Fair value hedge on interest rate swap agreements			145
Balance as of end-of-period		$	6,070

Details underlying the recognition of a gain (loss) on the early extinguishment of debt (in millions) reported within interest expense on our Consolidated Statements of Comprehensive Income (Loss) for the three and nine months ended September 30, 2019, were as follows:



Principal balance outstanding prior to payoff ⁽¹⁾	$	109
Unamortized debt issuance costs and discounts		(1	)
Amount paid to retire debt		(150	)
Gain (loss) on early extinguishment of debt, pre-tax	$	(42	)

⁽¹⁾During the third quarter of 2019, we repurchased $105 million of our 6.15% senior notes due 2036 and $4 million of our 4.85% senior notes due 2021.

On July 31, 2019, we refinanced our existing credit facility with a syndicate of banks. This facility (the “credit facility”) allows for the issuance of LOCs and borrowing of up to $2.25 billion. The credit facility is unsecured and has a commitment termination date of July 31, 2024. The LOCs under the credit facility are used primarily to satisfy reserve credit requirements of (i) our domestic insurance companies for which reserve credit is provided by our affiliated reinsurance companies and (ii) certain ceding companies of our legacy reinsurance business.

Customary terms and conditions, including covenants restricting our ability to incur liens, merge or consolidate with another entity where we are not the surviving entity and dispose of all or substantially all of our assets;

Financial covenants including maintenance of a minimum consolidated net worth (as defined in the credit agreement) equal to the sum of $10.6 billion plus 50% of the aggregate net proceeds of equity issuances received by us as set forth in the credit agreement; and a debt-to-capital ratio as defined in accordance with the credit facility not to exceed 0.35 to 1.00;

A cap on secured non-operating indebtedness and non-operating indebtedness of our subsidiaries equal to 7.5% of total capitalization, as defined in accordance with the credit agreement; and

Customary events of default, subject to certain materiality thresholds and grace periods for certain of those events of default.

Upon an event of default, the credit agreement provides that, among other things, the commitments may be terminated and the loans then outstanding may be declared due and payable. As of September 30, 2019, we were in compliance with all such covenants.