VALUATION AND QUALIFYING ACCOUNTS

12 Months Ended

Dec. 31, 2016

Valuation And Qualifying Accounts [Abstract]

VALUATION AND QUALIFYING ACCOUNTS

14. VALUATION AND QUALIFYING ACCOUNTS
The following table summarizes the activity and ending balances in our allowance for doubtful accounts and estimated revenue adjustments (amounts in millions):
Allowance for Doubtful Accounts
	Year End	Balance at Beginning of Year		Provision for Doubtful Accounts (1)		Write-Offs		Balance at End of Year
	2016	$	16.5	$	19.5	$	(18.3)	$	17.7
	2015		14.3		14.1		(11.9)		16.5
	2014		14.2		16.4		(16.3)		14.3
	(1) Includes $0.1 million from discontinued operations for the year ended December 31, 2014.
Estimated Revenue Adjustments
	Year End	Balance at Beginning of Year		Provision for Estimated Revenue Adjustments (1)		Write-Offs		Balance at End of Year
	2016	$	4.0	$	7.9	$	(7.8)	$	4.1
	2015		3.1		6.1		(5.2)		4.0
	2014		3.9		5.1		(5.9)		3.1
	(1) Includes $0.1 million from discontinued operations for the year ended December 31, 2014.