v3.3.1.900
Schedule II - Valuation and Qualifying Accounts (Tables)
 12 Months Ended
Dec. 31, 2015
Valuation and Qualifying Accounts Disclosure [Line Items]  
Schedule of Valuation and Qualifying Accounts Disclosure
SCHEDULE II—VALUATION AND QUALIFYING ACCOUNTS AND RESERVES
 
 
 
Additions
 
 
 
 
 
 
 
Balance at Beginning of Period
 
Charged to Costs and Expenses
 
Deductions
 
Other Activity
 
Balance at End of Period
 
(in millions)
December 31, 2015:
 
 
 
 
 
 
 
 
 
Allowance for doubtful accounts
$
21

 
$
11

 
$
(7
)
 
$
1

 
$
26

Tax valuation allowance (a)
$
747

 
$
192

 
$
—

 
$
(29
)
 
$
910

December 31, 2014:
 
 
 
 
 
 
 
 
 
Allowance for doubtful accounts (b)
$
60

 
$
10

 
$
(5
)
 
$
(44
)
 
$
21

Tax valuation allowance (a)
$
642

 
$
187

 
$
(15
)
 
$
(67
)
 
$
747

December 31, 2013:
 
 
 
 
 
 
 
 
 
Allowance for doubtful accounts
$
61

 
$
7

 
$
(9
)
 
$
1

 
$
60

Tax valuation allowance (a)
$
502

 
$
125

 
$
(17
)
 
$
32

 
$
642


(a)
Additions Charged to Costs and Expenses are primarily related to taxable losses for which the tax benefit has been reserved.
(b)
Other Activity primarily represents the reclassification of balances related to billing adjustments to accounts receivable.