XML 49 R37.htm IDEA: XBRL DOCUMENT v3.19.1
Significant Accounting Policies - Quality Incentive Premium Revenue Recognized (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Schedule of Premium Revenue by Health Plan Type [Line Items]    
Maximum available quality incentive premium - current period $ 45 $ 40
Quality incentive premium revenue recognized in current period:    
Earned current period 26 24
Earned prior periods 20 11
Total $ 46 $ 35
Quality incentive premium revenue recognized as a percentage of total premium revenue 1.20% 0.80%
Minimum | Select Health Plans    
Schedule of Premium Revenue by Health Plan Type [Line Items]    
Percentage of additional incremental revenue earned 1.00%  
Maximum | Select Health Plans    
Schedule of Premium Revenue by Health Plan Type [Line Items]    
Percentage of additional incremental revenue earned 4.00%