ACQUISITIONS - Purchase Price Allocation (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Dec. 31, 2017
Final purchase price allocations      
Goodwill $ 7,036   $ 7,018
Series of individual business acquisitions      
Final purchase price allocations      
Current assets 2 $ 1  
Property and equipment 3 1  
Other intangible assets 1 2  
Goodwill 20 10  
Other long-term assets 1 0  
Current liabilities (1) (2)  
Long-term liabilities (1) (1)  
Redeemable noncontrolling interests in equity of consolidated subsidiaries (9) 0  
Noncontrolling interests 0 (3)  
Cash paid, net of cash acquired (16) (6)  
Gains on consolidations 0 2  
Transaction costs related to prospective and closed acquisitions $ 2 $ 2