SEGMENT INFORMATION - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Segment	Sep. 30, 2011
Segment Reporting Disclosure [Line Items]
Number of reportable segments			3
Member co-share amounts and government subsidies	$ 1,200,000,000	$ 1,100,000,000	$ 3,500,000,000	$ 3,100,000,000
Depreciation and amortization classified as benefit expense	3,000,000	7,000,000	20,000,000	24,000,000
Litigation settlement associated with Military services business			46,000,000
Retail
Segment Reporting Disclosure [Line Items]
Prior Period Medical Claims Reserve Development	38,000,000	32,000,000	95,000,000	104,000,000
Other Businesses
Segment Reporting Disclosure [Line Items]
Prior Period Medical Claims Reserve Development	2,000,000	7,000,000	11,000,000	5,000,000
Employer Group
Segment Reporting Disclosure [Line Items]
Prior Period Medical Claims Reserve Development	$ 14,000,000	$ 9,000,000	$ 4,000,000	$ 42,000,000