4. Debt

Long-term debt consists of the following unsecured senior debt:

	Effective Rate			Coupon Rate			Outstanding
Maturity (Dollars in Millions)	Effective Rate			Coupon Rate			May 5, 2018		February 3, 2018 & April 29, 2017
2021		4.81	%		4.00	%	$	426	$	650
2023		3.25	%		3.25	%		350		350
2023		4.78	%		4.75	%		184		300
2025		4.25	%		4.25	%		650		650
2029		7.36	%		7.25	%		42		99
2033		6.05	%		6.00	%		112		166
2037		6.89	%		6.88	%		101		150
2045		5.57	%		5.55	%		450		450
		4.76	%				$	2,315	$	2,815

Long-term debt is net of unamortized debt discounts and deferred financing costs of $14 million at May 5, 2018, $18 million at February 3, 2018, and $20 million at April 29, 2017.

Our long-term debt is classified as Level 1, financial instruments with unadjusted, quoted prices listed on active market exchanges. The estimated fair value of our long-term debt was $2.3 billion at May 5, 2018, $2.9 billion at February 3, 2018 and $2.8 billion at April 29, 2017.

In April 2018, we completed a cash tender offer for $500 million of senior unsecured debt. We recognized a $42 million loss on extinguishment of debt in the first quarter of 2018 which includes $35 million of premiums paid to holders as a result of the tender offer, a $4 million non-cash write-off of an interest rate hedge on tendered debt, and a $3 million non-cash write-off of deferred financing costs and original issue discounts associated with the extinguished debt.