v3.8.0.1
Summary of Significant Accounting Policies (Tables)
 12 Months Ended
Dec. 31, 2017
Accounting Policies [Abstract]  
Schedule Of Property Software And Equipment Depreciation Periods
Property, software and equipment are depreciated over the following periods:
Fixed Asset
 
Depreciation Period
Buildings and land improvements
 
5 - 40 years
Computer hardware and software
 
2 - 7 years
Furniture and equipment
 
3 - 10 years
Land improvements
 
3 - 20 years
Leasehold improvements
 
1 - 20 years
Schedule Of Amortization Period For Intangible Assets
Intangible assets are amortized using the straight-line method over the following periods:
Intangible Asset
 
Amortization Period
Purchased contract rights
 
5 - 15 years
Provider contracts
 
4 - 15 years
Customer relationships
 
3 - 15 years
Trade names
 
7 - 20 years
Developed technologies
 
5 years
Schedule Of Allowance For Uncollectible Accounts
Activity in the allowance for uncollectible accounts for the years ended December 31, is summarized below ($ in millions):
 
2017
 
2016
 
2015
Allowances, beginning of year
$
29

 
$
10

 
$
5

Amounts charged to expense
35

 
33

 
12

Write-offs of uncollectible receivables
(40
)
 
(14
)
 
(7
)
Allowances, end of year
$
24

 
$
29

 
$
10