XML 187 R158.htm IDEA: XBRL DOCUMENT v3.6.0.2
Segment Information - Concentration Risk (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Sep. 30, 2016
CMS [Member]        
Concentration Risk [Line Items]        
Net receivables from CMS $ 600 $ 1,500    
Geographic Concentration Risk [Member] | Single Foreign Country [Member]        
Concentration Risk [Line Items]        
Concentration Risk, Benchmark Description Revenues from external customers      
Risk corridor program [Member]        
Concentration Risk [Line Items]        
Risk corridor receivable $ 124     $ 124
Allowance for risk corridor receivable 124      
Pre-tax income not recognized for risk corridor receivables $ 25      
Revenues From External Customers [Member] | Geographic Concentration Risk [Member] | Maximum [Member] | Single Foreign Country [Member]        
Concentration Risk [Line Items]        
Concentration Risk, Percentage 5.00% 5.00% 5.00%  
Revenue Consolidated [Member] | Government Contracts Concentration Risk [Member] | CMS [Member]        
Concentration Risk [Line Items]        
Concentration Risk, Percentage 20.00% 21.00% 21.00%  
Concentration Risk, Benchmark Description Consolidated revenues