Contract Balances

12 Months Ended

Dec. 31, 2021

Contract Balances

Contract Balances

18.    Contract Balances

Our valuation and qualifying accounts as of December 31, 2021, 2020 and 2019 were as follows:

Allowance for credit losses	Balance at Beginning of Year		Current Period Provision for Expected Credit Losses		Write-offs Charged Against Allowance		Acquisitions	Balance at End of Year
	(In thousands)
For the years ended:
December 31, 2021	$	72,278	$	54,083	$	(87,919)	92	$	38,534
December 31, 2020	$	19,280	$	84,697	$	(56,075)	24,376	$	72,278
December 31, 2019	$	16,966	$	69,866	$	(67,552)	—	$	19,280

Contract liabilities arise when we bill our customers and receive consideration in advance of providing the service. Contract liabilities are recognized as revenue when the service has been provided to the customer. Contract liabilities are recorded in “Deferred revenue and other” and “Long-term deferred revenue and other long-term liabilities” on our Consolidated Balance Sheets.

	As of December 31,
	2021		2020
	(In thousands)
Contract liabilities	$	714,428	$	778,832

Our beginning of period contract liability recorded as customer contract revenue during 2021 was $776 million.

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.