Debt

9 Months Ended

Oct. 31, 2020

The carrying values of the Company's borrowings were as follows (in millions):


Instrument	Date of issuance	Maturity date	Effective interest rate for the three months ended October 31, 2020	October 31, 2020		January 31, 2020

2023 Senior Notes	April 2018	April 2023	3.26%	$	996	$	995
2028 Senior Notes	April 2018	April 2028	3.70%	1,490		1,489
Loan assumed on 50 Fremont	February 2015	June 2023	3.75%	190		193

Total carrying value of debt				2,676		2,677
Less current portion of debt				(4)		(4)
Total noncurrent debt				$	2,672	$	2,673

Each of the Company's debt agreements requires it to maintain compliance with certain debt covenants, all of which the Company was in compliance with as of October 31, 2020.

The total estimated fair value of the Company's 2023 and 2028 Senior Notes as of October 31, 2020 and January 31, 2020 was $2.8 billion and $2.7 billion, respectively. The fair value was determined based on the closing trading price per $100 of the 2023 and 2028 Senior Notes as of the last day of trading for the third quarter of fiscal 2021 and last day of trading for the fourth quarter of fiscal 2020, respectively, and is deemed a Level 2 liability within the fair value measurement framework.

The expected future principal payments for all borrowings as of October 31, 2020 is as follows (in millions):


Fiscal period:
Remaining three months of fiscal 2021	$	1
Fiscal 2022	4
Fiscal 2023	4
Fiscal 2024	1,182
Fiscal 2025	0
Thereafter	1,500
Total principal outstanding	$	2,691

Revolving Credit Facility

In April 2018, the Company entered into a Second Amended and Restated Credit Agreement ("Revolving Loan Credit Agreement") with Wells Fargo Bank, National Association, and certain other institutional lenders that provides for $1.0 billion unsecured revolving credit facility (“Credit Facility”) that matures in April 2023. The Revolving Loan Credit Agreement amended and restated the Company’s existing revolving credit facility dated July 2016. The Company may use the proceeds of future borrowings under the Credit Facility for refinancing other indebtedness, working capital, capital expenditures and other general corporate purposes, including permitted acquisitions.

There were no outstanding borrowings under the Credit Facility as of October 31, 2020. The Company continues to pay a commitment fee on the available amount of the Credit Facility, which is included within other expense in the Company's condensed consolidated statement of operations.

Interest Expense on Debt

The following table sets forth total interest expense recognized related to debt (in millions):


	Three Months Ended October 31,				Nine Months Ended October 31,
	2020		2019		2020		2019
Contractual interest expense	$	24	$	26	$	72	$	82
Amortization of debt issuance costs	1		1		3		3
	$	25	$	27	$	75	$	85