Accounts Receivable (Tables)

12 Months Ended

Dec. 31, 2019

Receivables [Abstract]

Schedule of the entity's accounts receivable balances

The following table presents details of our accounts receivable balances:

	As of December 31,
	2019			2018
	(Dollars in millions)
Trade and purchased receivables	$	471		491
Earned and unbilled receivables	81			92
Other	1			4
Total accounts receivable	553			587
Less: allowance for doubtful accounts	(39		)	(41	)
Accounts receivable, less allowance	$	514		546

Schedule of the entity's allowance for doubtful accounts

The following table presents details of our allowance for doubtful accounts:

	Beginning Balance		Additions	Deductions		Ending Balance
	(Dollars in millions)
2019	$	41	51	(53	)	39
2018	$	47	60	(66	)	41
2017	$	53	74	(80	)	47