Long-term debt at December 31, 2017 and March 31, 2018 was as follows (in thousands):



	December 31, 2017			March 31, 2018
Commercial paper	$	—		$	—
6.40% Notes due 2018	250,000			250,000
6.55% Notes due 2019	550,000			550,000
4.25% Notes due 2021	550,000			550,000
3.20% Notes due 2025	250,000			250,000
5.00% Notes due 2026	650,000			650,000
6.40% Notes due 2037	250,000			250,000
4.20% Notes due 2042	250,000			250,000
5.15% Notes due 2043	550,000			550,000
4.20% Notes due 2045	250,000			250,000
4.25% Notes due 2046	500,000			500,000
4.20% Notes due 2047	500,000			500,000
Face value of long-term debt	4,550,000			4,550,000
Unamortized debt issuance costs⁽¹⁾	(29,472		)	(28,972		)
Net unamortized debt premium (discount)⁽¹⁾	215			(554		)
Net unamortized amount of gains from historical fair value hedges⁽¹⁾	3,749			2,784
Long-term debt, net, including current portion	4,524,492			4,523,258
Less: Current portion of long-term debt, net	250,974			250,511
Long-term debt, net	$	4,273,518		$	4,272,747

(1) Debt issuance costs, note discounts and premiums and realized gains and losses of historical fair value hedges are being amortized or accreted to the applicable notes over the respective lives of those notes.