Accounts Receivable

12 Months Ended

Dec. 31, 2020

The following table presents details of our accounts receivable balances:


	As of December 31,
	2020		2019
	(Dollars in millions)
Trade and purchased receivables	$	1,717	1,971
Earned and unbilled receivables	345		374
Other	91		20
Total accounts receivable	2,153		2,365
Less: allowance for credit losses	(191)		(106)
Accounts receivable, less allowance	$	1,962	2,259

We are exposed to concentrations of credit risk from our customers. We generally do not require collateral to secure our receivable balances. We have agreements with other communications service providers whereby we agree to bill and collect on their behalf for services rendered by those providers to our customers within our local service area. We purchase accounts receivable from other communications service providers primarily on a recourse basis and include these amounts in our accounts receivable balance. We have not experienced any significant loss associated with these purchased receivables.

The following table presents details of our allowance for credit losses accounts:


	Beginning Balance		Additions	Deductions	Ending Balance
	(Dollars in millions)
2020(1)	$	106	189	(104)	191
2019	142		145	(181)	106
2018	164		153	(175)	142

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(1)On January 1, 2020, we adopted ASU 2016-13 "Measurement of Credit Losses on Financial Instruments" and recognized a cumulative adjustment to our accumulated deficit as of the date of adoption of $9 million, net of $2 million tax effect. This adjustment is included within "Deductions". Please refer to Note 5 - Credit Losses on Financial instruments for more information.