Quarterly report pursuant to Section 13 or 15(d)

Affordable Care Act (Details)

v3.8.0.1
Affordable Care Act (Details) - USD ($)
$ in Millions
3 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Sep. 30, 2017
Dec. 31, 2016
Affordable Care Act [Abstract]        
Risk adjustment and reinsurance, pre-tax benefit, period increase (decrease) $ 48 $ 70    
Risk adjustment     $ (609) $ (425)
Reinsurance     15 122
Risk corridor     (8) (3)
Minimum MLR     (1) (18)
Cost sharing reductions     $ (180) $ (147)