Contract Balances

12 Months Ended

Dec. 31, 2019

Contract Balances

Contract Balances

15.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	$	16,956	$	69,866	$	(67,542)	$	19,280
December 31, 2018	$	15,056	$	98,461	$	(96,561)	$	16,956
December 31, 2017	$	17,440	$	124,143	$	(126,527)	$	15,056

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	$	624,626
Recognition of unearned revenue		(7,086,252)
Deferral of revenue		7,070,680
Balance as of December 31, 2019	$	609,054

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.