Accrued Expenses and Allowance for Doubtful Accounts (Tables)

12 Months Ended

Dec. 31, 2017

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Summary of Other Accrued Expenses

A summary of other accrued expenses at December 31 follows (dollars in millions):

	2017		2016
Professional liability risks	$	429	$	391
Interest		406		409
Taxes other than income		299		283
Other		849		952
	$	1,983	$	2,035

Summary of Allowance of Doubtful Accounts

A summary of activity for the allowance of doubtful accounts follows (dollars in millions):

	Balance at Beginning of Year		Provision for Doubtful Accounts		Accounts Written off, Net of Recoveries			Balance at End of Year
Allowance for doubtful accounts:
Year ended December 31, 2015	$	5,011	$	3,913	$	(3,598	)	$	5,326
Year ended December 31, 2016		5,326		3,257		(3,595	)		4,988
Year ended December 31, 2017		4,988		4,039		(3,539	)		5,488