Accounts Receivable

12 Months Ended

Dec. 31, 2017

Accounts Receivable [Abstract]

Accounts Receivable

(4)  Accounts Receivable:

The components of accounts receivable, net at December 31, 2017 and 2016 are as follows:

($ in millions)	2017		2016
Retail and Wholesale	$	801	$	979
Other		87		90
Less: Allowance for doubtful accounts		(69)		(131)
Accounts receivable, net	$	819	$	938

An analysis of the activity in the allowance for doubtful accounts for the years ended December 31, 2017, 2016 and 2015 is as follows:

($ in millions)	Balance at beginning of Period		Charged to Other Revenue		Charged (Credited) to Switched and Nonswitched Revenue and Other Accounts		Write-offs, net of Recoveries		Balance at end of Period
2015	$	72	$	67	$	(17)	$	(65)	$	57
2016	$	57	$	164	$	15	$	(105)	$	131
2017	$	131	$	109	$	(22)	$	(149)	$	69

We maintain an allowance for doubtful accounts based on our estimate of our ability to collect accounts receivable. The provision for uncollectible amounts was $87 million, $179million, and $50 million for the years ended December 31, 2017, 2016 and 2015, respectively. Our allowance for doubtful accounts increased in 2016 primarily as a result of the customer account balances related to CTF Operations subsequent to the CTF Acquisition.  Our allowance for doubtful accounts decreased during 2017 primarily as a result of resolutions of carrier disputes and increased collection efforts on delinquent balances in both our CTF and Legacy markets. Resolutions reached with carriers resulted in a reduction of our reserves of $39 million in 2017.