Long-term Debt (Tables)

6 Months Ended

Jun. 30, 2020

Debt Disclosure [Abstract]

Long-term Debt

The components of long-term debt, including the effects of issuance costs and issuance discounts, are as follows:

	As of June 30, 2020		As of December 31, 2019
	(in millions)
Outstanding debt principal balances:
7.50% senior notes due 2020	$	—	$	450
3.45% senior notes due 2021	139		500
3.95% senior notes due 2022	244		600
0.25% convertible senior notes due 2025	1,323		—
4.45% senior notes due 2026	500		500
7.20% senior notes due 2028	241		250
	2,447		2,300
Issuance costs and discounts	(254)		(11)
Total debt	2,193		2,289
Less current portion of long-term debt	(139)		(450)
Long-term debt	$	2,054	$	1,839

The principal amount and related unamortized issuance costs and discount on the Convertible Notes, are as follows:

	As of June 30, 2020
	(in millions)
Principal amount of Convertible Notes	$	1,323
Unamortized issuance costs and discount on Convertible Notes (a)	(247)
Net carrying value	$	1,076

______________________

(a)Amortized to interest expense at an effective interest rate of 4.27 percent over five years.

Interest Costs

The interest costs recognized on the Convertible Notes, are as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
	2020		2019		2020		2019
	(in millions)
Contractual interest coupon	$	1	$	—	$	1	$	—
Amortization of debt discount and issuance costs	8		—		8		—
	$	9	$	—	$	9	$	—