Contract Balances

12 Months Ended

Dec. 31, 2020

Contract Balances

Contract Balances

15.Contract Balances

Our valuation and qualifying accounts as of December 31, 2020, 2019 and 2018 were as follows:

Allowance for credit losses	Balance at Beginning of Period		Current Period Provision for Expected Credit Losses		Write-offs Charged Against Allowance		Balance at End of Period
	(In thousands)
For the years ended:
December 31, 2020	$	19,280	$	76,441	$	(52,488)	$	43,233
December 31, 2019	$	16,956	$	69,866	$	(67,542)	$	19,280
December 31, 2018	$	15,056	$	98,461	$	(96,561)	$	16,956

Deferred revenue related to contracts with our customers is recorded in “Deferred revenue and other” and “Long-term deferred revenue and other long-term liabilities” on our Consolidated Balance Sheets. Changes in deferred revenue related to contracts with our customers were as follows:

	Contract
	Liabilities
	(In thousands)
Balance as of December 31, 2019	$	609,054
Recognition of unearned revenue		(5,852,961)
Deferral of revenue		5,837,704
Balance as of December 31, 2020	$	593,797

We apply a practical expedient and do not disclose the value of the remaining performance obligations for contracts that are less than one year in duration, which represent a substantial majority of our revenue. As such, the amount of revenue related to unsatisfied performance obligations is not necessarily indicative of our future revenue.