Contract Balances

12 Months Ended

Dec. 31, 2019

Contract Balances

Contract Balances

17.    Contract Balances

Our valuation and qualifying accounts as of December 31, 2019, 2018 and 2017 were as follows:

Allowance for doubtful accounts	Balance at Beginning of Year		Charged to Costs and Expenses		Deductions		Balance at End of Year
	(In thousands)
For the years ended:
December 31, 2019	$	16,966	$	69,866	$	(67,552)	$	19,280
December 31, 2018	$	15,511	$	98,575	$	(97,120)	$	16,966
December 31, 2017	$	18,399	$	124,126	$	(127,014)	$	15,511

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, 2018	$	635,018
Recognition of unearned revenue		(7,197,364)
Deferral of revenue		7,175,618
Balance as of December 31, 2019	$	613,272

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.