Accounts Receivable (Tables)

12 Months Ended

Dec. 31, 2017

Accounts Receivable [Abstract]

Accounts Receivable

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

Schedule Of Allowance For Doubtful Accounts

($ 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