CONTRACT BALANCES - Hospital Operations and Other Segment (Details) - Hospital Operations and other - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Receivables    
Balance at beginning of period $ 171 $ 0
Balance at end of period 158 0
Increase/(decrease) $ (13) $ 0
Contract assets, percentage to be reclassified to receivable within 90 days 89.00%