Long-term Debt and Interest Expense (Tables)

12 Months Ended

Dec. 31, 2020

Debt Disclosure [Abstract]

Components of long-term debt

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

	As of December 31,
	2020		2019
	(in millions)
Outstanding debt principal balances:
7.50% senior notes due 2020	$	—	$	450
3.45% senior notes due 2021	140		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
1.90% senior notes due 2030	1,100		—
	3,548		2,300
Issuance costs and discounts	(248)		(11)
Total debt	3,300		2,289
Less current portion of long-term debt	140		450
Long-term debt	$	3,160	$	1,839

Principal maturities of long-term debt

Principal payments scheduled to be made on the Company's long-term debt are as follows (in millions):

2021	$	140
2022	$	244
2023	$	—
2024	$	—
2025	$	1,323
Thereafter	$	1,841

Interest expense

Interest expense activity is as follows:

	Year Ended December 31,
	2020		2019		2018
	(in millions)
Cash payments for interest	$	102	$	117	$	133
Accretion of finance lease	17		4		—
Amortization of issuance discounts	29		1		1
Amortization of capitalized loan fees	5		4		4
Net changes in accruals	(19)		—		(6)
Interest incurred	134		126		132
Less capitalized interest	(5)		(5)		(6)
Total interest expense	$	129	$	121	$	126