XML 101 R56.htm IDEA: XBRL DOCUMENT v3.8.0.1
Significant Accounting Policies - 3R Program Receivables (Payables) (Details) - USD ($)
$ in Millions
Dec. 31, 2017
Dec. 31, 2016
Accounting Policies [Abstract]    
Risk adjustment payable, Current Benefit Year $ (912)  
Risk adjustment payable, Prior Benefit Years 0  
Risk adjustment payable, Total (912) $ (522)
Reinsurance receivable, Current Benefit Year 0  
Reinsurance receivable, Prior Benefit Years 10  
Reinsurance receivable, Total 10 55
Risk corridor payable, Current Benefit Year 0  
Risk corridor payable, Prior Benefit Years 0  
Risk corridor payable, Total 0 (1)
Minimum MLR payable, Current Benefit Year (2)  
Minimum MLR payable, Prior Benefit Years 0  
Minimum MLR payable, Total $ (2) $ (1)