GOODWILL AND OTHER INTANGIBLE ASSETS - Changes in Carrying Amount of Goodwill by Reportable Segments (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Beginning balance	$ 3,272	$ 3,265
Acquisitions	9	7
Ending balance	3,281	3,272
Retail
Goodwill [Roll Forward]
Beginning balance	1,059	1,059
Acquisitions	0	0
Ending balance	1,059	1,059
Group and Specialty
Goodwill [Roll Forward]
Beginning balance	261	261
Acquisitions	0	0
Ending balance	261	261
Healthcare Services
Goodwill [Roll Forward]
Beginning balance	1,952	1,945
Acquisitions	9	7
Ending balance	$ 1,961	$ 1,952