SEGMENT INFORMATION - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012 Segment	Jun. 30, 2011	Jun. 30, 2012 Segment	Jun. 30, 2011
Segment Reporting Disclosure [Line Items]
Number of reportable segments	3		3
Member co-share amounts and government subsidies	$ 1,200,000,000	$ 1,000,000,000	$ 2,400,000,000	$ 2,000,000,000
Depreciation And Amortization Classified As Benefit Expense	9,000,000	7,000,000	17,000,000	17,000,000
Litigation settlement associated with Military services business	46,000,000		46,000,000
Retail
Segment Reporting Disclosure [Line Items]
Prior Period Medical Claims Reserve Development	24,000,000	32,000,000	57,000,000	72,000,000
Employer Group
Segment Reporting Disclosure [Line Items]
Prior Period Medical Claims Reserve Development	12,000,000	(8,000,000)	(18,000,000)	33,000,000
Other Businesses
Segment Reporting Disclosure [Line Items]
Prior Period Medical Claims Reserve Development	$ 4,000,000	$ 9,000,000	$ 9,000,000	$ 12,000,000