Humana (HUM) 10-Q 7 Nov 14 2014 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2014
Document Information [Line Items]	'
Document Type	'10-Q
Amendment Flag	'false
Document Period End Date	30-Sep-14
Document Fiscal Year Focus	'2014
Document Fiscal Period Focus	'Q3
Trading Symbol	'HUM
Entity Registrant Name	'HUMANA INC
Entity Central Index Key	'0000049071
Current Fiscal Year End Date	'--12-31
Entity Filer Category	'Large Accelerated Filer
Entity Common Stock, Shares Outstanding	153,334,953

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (Unaudited) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$2,705	$1,138
Investment securities	8,088	8,090
Receivables, less allowance for doubtful accounts of $135 in 2014 and $118 in 2013:	1,004	950
Other current assets	3,839	2,122
Total current assets	15,636	12,300
Property and equipment, net	1,349	1,218
Long-term investment securities	1,947	1,710
Goodwill	3,695	3,733
Other long-term assets	1,704	1,774
Total assets	24,331	20,735
Current liabilities:	'	'
Benefits payable	4,676	3,893
Trade accounts payable and accrued expenses	2,068	1,821
Current portion of long-term debt	512	0
Book overdraft	267	403
Unearned revenues	246	206
Total current liabilities	7,769	6,323
Long-term debt	3,826	2,600
Future policy benefits payable	2,299	2,207
Other long-term liabilities	312	289
Total liabilities	14,206	11,419
Commitments and contingencies	'	'
Stockholders’ equity:	'	'
Preferred stock, $1 par; 10,000,000 shares authorized; none issued	0	0
Common stock, $0.16 2/3 par; 300,000,000 shares authorized; 197,843,933 shares issued at September 30, 2014 and 196,275,506 shares issued at December 31, 2013	33	33
Capital in excess of par value	2,400	2,267
Retained earnings	9,813	8,942
Accumulated other comprehensive income	233	158
Treasury stock, at cost, 44,508,980 shares at September 30, 2014 and 42,245,097 shares at December 31, 2013	-2,354	-2,084
Total stockholders’ equity	10,125	9,316
Total liabilities and stockholders’ equity	$24,331	$20,735

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, except Share data, unless otherwise specified
Receivables, allowance for doubtful accounts	$135	$118
Preferred stock, par	$1	$1
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, issued	0	0
Common stock, par	$0.17	$0.17
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	197,843,933	196,275,506
Treasury stock, shares	44,508,980	42,245,097

Condensed_Consolidated_Stateme

Condensed Consolidated Statements Of Income (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Revenues:	'	'	'	'
Premiums	$11,607	$9,698	$34,274	$29,267
Services	536	528	1,620	1,581
Investment income	95	93	278	278
Total revenues	12,238	10,319	36,172	31,126
Operating expenses:	'	'	'	'
Benefits	9,666	8,075	28,417	24,361
Operating costs	1,898	1,540	5,518	4,447
Depreciation and amortization	85	83	246	243
Total operating expenses	11,649	9,698	34,181	29,051
Income from operations	589	621	1,991	2,075
Interest expense	38	35	108	105
Income before income taxes	551	586	1,883	1,970
Provision for income taxes	261	218	881	709
Net income	$290	$368	$1,002	$1,261
Basic earnings per common share (in dollars per share)	$1.87	$2.34	$6.46	$7.98
Diluted earnings per common share (in dollars per share)	$1.85	$2.31	$6.39	$7.90
Dividends per common share (in dollars per share)	$0.28	$0.27	$0.83	$0.80

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements Of Comprehensive Income (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Net income	$290	$368	$1,002	$1,261
Other comprehensive income (loss):	'	'	'	'
Change in gross unrealized investment gains/losses	-36	-16	128	-286
Effect of income taxes	13	6	-47	105
Total change in unrealized investment gains/losses, net of tax	-23	-10	81	-181
Reclassification adjustment for net realized gains included in investment income	-6	-4	-9	-14
Effect of income taxes	2	1	3	5
Total reclassification adjustment, net of tax	-4	-3	-6	-9
Other comprehensive income (loss), net of tax	-27	-13	75	-190
Comprehensive income	$263	$355	$1,077	$1,071

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements Of Cash Flows (Unaudited) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities	'	'
Net income	$1,002	$1,261
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Net realized capital gains	-9	-14
Stock-based compensation	76	73
Depreciation and amortization	325	312
(Benefit) provision for deferred income taxes	-30	31
Changes in operating assets and liabilities, net of effect of businesses acquired and dispositions:	'	'
Receivables	-68	-89
Other assets	-960	-165
Benefits payable	783	287
Other liabilities	238	24
Unearned revenues	40	-32
Other, net	28	44
Net cash provided by operating activities	1,425	1,732
Cash flows from investing activities	'	'
Acquisitions, net of cash acquired	-3	-161
Proceeds from sale of business	72	33
Purchases of property and equipment	-361	-310
Purchases of investment securities	-1,949	-2,665
Maturities of investment securities	702	853
Proceeds from sales of investment securities	1,171	1,107
Net cash used in investing activities	-368	-1,143
Cash flows from financing activities	'	'
Receipts (withdrawals) from contract deposits, net	-743	-201
Proceeds from issuance of senior notes, net	1,733	0
Change in book overdraft	-136	-51
Common stock repurchases	-270	-325
Dividends paid	-129	-125
Excess tax benefit from stock-based compensation	10	6
Proceeds from stock option exercises and other	45	56
Net cash provided by (used in) financing activities	510	-640
Increase (decrease) in cash and cash equivalents	1,567	-51
Cash and cash equivalents at beginning of period	1,138	1,306
Cash and cash equivalents at end of period	2,705	1,255
Supplemental cash flow disclosures:	'	'
Interest payments	83	82
Income tax payments, net	$852	$724

BASIS_OF_PRESENTATION

BASIS OF PRESENTATION	9 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
BASIS OF PRESENTATION	'
	BASIS OF PRESENTATION
	The accompanying condensed consolidated financial statements are presented in accordance with generally accepted accounting principles for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the disclosures normally required by accounting principles generally accepted in the United States of America, or GAAP, or those normally made in an Annual Report on Form 10-K. The year-end condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by GAAP. For further information, the reader of this Form 10-Q should refer to our Form 10-K for the year ended December 31, 2013, that was filed with the Securities and Exchange Commission, or the SEC, on February 19, 2014, as retrospectively adjusted as it relates to the effects of the business segment reclassifications as described more fully below in our current report on Form 8-K filed with the SEC on September 16, 2014. We refer to the Form 10-K and Form 8-K collectively as the “2013 Form 10-K” in this document. References throughout this document to “we,” “us,” “our,” “Company,” and “Humana” mean Humana Inc. and its subsidiaries.
	The preparation of our condensed consolidated financial statements in accordance with GAAP requires us to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. The areas involving the most significant use of estimates are the estimation of benefits payable, the impact of risk sharing provisions related to our Medicare contracts, the valuation and related impairment recognition of investment securities, and the valuation and related impairment recognition of long-lived assets, including goodwill. These estimates are based on knowledge of current events and anticipated future events, and accordingly, actual results may ultimately differ materially from those estimates. Refer to Note 2 to the consolidated financial statements included in our 2013 Form 10-K for information on accounting policies that we consider in preparing our consolidated financial statements.
	The financial information has been prepared in accordance with our customary accounting practices and has not been audited. In our opinion, the information presented reflects all adjustments necessary for a fair statement of interim results. All such adjustments are of a normal and recurring nature.
	Business Segment Reclassifications
	On January 1, 2014, we reclassified certain of our businesses from our Healthcare Services segment to our Employer Group segment to correspond with internal management reporting changes. Our reportable segments remain the same and prior period segment financial information has been recast to conform to the 2014 presentation. See Note 13 for segment financial information.
	Health Care Reform
	The Patient Protection and Affordable Care Act and The Health Care and Education Reconciliation Act of 2010 (which we collectively refer to as the Health Care Reform Law) enacted significant reforms to various aspects of the U.S. health insurance industry. Certain of these reforms became effective January 1, 2014, including an annual insurance industry premium-based fee and the establishment of federally-facilitated or state-based exchanges coupled with three premium stabilization programs, as described more fully below.
	The Health Care Reform Law imposes an annual premium-based fee on health insurers for each calendar year beginning on or after January 1, 2014 which is not deductible for tax purposes. We are required to estimate a liability for the health insurer fee and record it in full once qualifying insurance coverage is provided in the applicable calendar year in which the fee is payable with a corresponding deferred cost that is amortized ratably to expense over the same calendar year. In September 2014, we paid the federal government $562 million for the annual health insurance industry fee attributed to calendar year 2014, in accordance with the Health Care Reform Law. We recorded the deferred cost in other current assets in our condensed consolidated financial statements. Amortization of the deferred cost resulted in operating cost expense of approximately $421 million for the nine months ended September 30, 2014 and a remaining deferred cost asset balance of approximately $141 million at September 30, 2014. No such amounts were recorded at December 31, 2013 as the qualifying insurance coverage was not provided until January 1, 2014.
	The Health Care Reform Law also establishes risk spreading premium stabilization programs effective January 1, 2014. The risk spreading programs are applicable to certain of our commercial medical insurance products. In the aggregate, our commercial medical insurance products represented approximately 17.7% of our total premiums and services revenue for the nine months ended September 30, 2014. These programs, commonly referred to as the 3Rs, include a permanent risk adjustment program, a transitional reinsurance program, and a temporary risk corridors program designed to more evenly spread the financial risk borne by issuers and to mitigate the risk that issuers would have mispriced products. The transitional reinsurance and temporary risk corridors programs are for years 2014 through 2016, with potential for additional reinsurance recoveries through 2018 to the extent funds are available. Policies issued prior to March 23, 2010 are considered grandfathered policies and are exempt from the 3Rs. Certain states have allowed non-grandfathered policies issued prior to January 1, 2014 to extend the date of required transition to policies compliant with the Health Care Reform Law to as late as 2017. Accordingly, such policies are exempt from the 3Rs until they transition to policies compliant with the Health Care Reform Law.
	The permanent risk adjustment program adjusts the premiums that commercial individual and small group health insurance issuers receive based on the demographic factors and health status of each member as derived from current year medical diagnosis as reported throughout the year. This program transfers funds from lower risk plans to higher risk plans within similar plans in the same state. The risk adjustment program is applicable to commercial individual and small group health plans (except certain exempt and grandfathered plans as discussed above) operating both inside and outside of the health insurance exchanges established under the Health Care Reform Law. Under the risk adjustment program, a risk score is assigned to each covered member to determine an average risk score at the individual and small group level by legal entity in a particular market in a state. Additionally, an average risk score is determined for the entire subject population for each market in each state. Settlements are determined on a net basis by legal entity and state. Each health insurance issuer’s average risk score is compared to the state’s average risk score. Plans with an average risk score below the state average will pay into a pool and health insurance issuers with an average risk score that is greater than the state average risk score will receive money from that pool. We generally rely on providers, including certain network providers who are our employees, to appropriately document all medical data, including the diagnosis codes submitted with claims, as the basis for our risk scores under the program. Our estimate of amounts receivable and/or payable under the risk adjustment program is based on our estimate of both our own and the state average risk scores. Assumptions used in these estimates include but are not limited to geographic considerations including our historical experience in markets we have participated in over a long period of time, member demographics including age and gender for our members and other health insurance issuers, our pricing model, sales data for each metal tier (different metal tiers yield different risk scores), the mix of previously underwritten membership as compared to new members in plans compliant with the Health Care Reform Law, published third party studies, and other publicly available data including regulatory plan filings. We expect to refine our estimates as new information becomes available, including additional data released by the Department of Health and Human Services, or HHS, regarding estimates of state average risk scores. Risk adjustment will be subject to audit by HHS beginning in 2014, however, there will be no payments associated with these audits for 2014 or 2015, the first two years of the program.
	The temporary risk corridor program applies to individual and small group Qualified Health Plans (or substantially equivalent plans), or QHPs, as defined by HHS, operating both inside and outside of the exchanges. Accordingly, plans subject to risk adjustment that are not QHPs, including our small group health plans, will not be subject to the risk corridor program. The risk corridor provisions limit issuer gains and losses by comparing allowable medical costs to a target amount, each defined/prescribed by HHS, and sharing the risk for allowable costs with the federal government. Allowable medical costs are adjusted for risk adjustment settlements, transitional reinsurance recoveries, and cost sharing reductions received from HHS. Variances from the target exceeding certain thresholds may result in HHS making additional payments to us or require us to refund HHS a portion of the premiums we received. While risk corridor payments from HHS were expected to be limited to the extent of the risk corridor collections received by HHS over the duration of the program, on May 16, 2014, HHS released clarifying guidance. This guidance indicated that risk corridor collections are expected to be sufficient to make all risk corridor payments. However, in the event of a shortfall, HHS has indicated that it intends to find other sources of funding for the risk corridors payments, subject to the availability of the requisite appropriations by Congress.
	We estimate and recognize adjustments to premiums revenue for the risk adjustment and risk corridor provisions by projecting our ultimate premium for the calendar year separately for individual and group plans by state and legal entity. Estimated calendar year settlement amounts are recognized ratably during the year and are revised each period to reflect current experience, including changes in risk scores derived from medical diagnoses submitted by providers. We record receivables or payables at the individual or group level within each state and legal entity and classify the amounts as current or long-term in the condensed consolidated balance sheets based on the timing of expected settlement.
	The transitional reinsurance program requires us to make reinsurance contributions for calendar years 2014 through 2016 to a state or HHS established reinsurance entity based on a national contribution rate per covered member as determined by HHS. While all commercial medical plans, including self-funded plans, are required to fund the reinsurance entity, only fully-insured non-grandfathered plans compliant with the Health Care Reform Law in the individual commercial market will be eligible for recoveries if individual claims exceed a specified threshold. Accordingly, we account for transitional reinsurance contributions associated with all commercial medical health plans other than these non-grandfathered individual plans as an assessment in operating costs in our condensed consolidated statements of income. We account for contributions made by individual commercial plans compliant with the Health Care Reform Law, which are subject to recoveries, as ceded premiums (a reduction of premiums) and similarly we account for any recoveries as ceded benefits (a reduction of benefits expense) in our condensed consolidated statements of income. For the nine months ended September 30, 2014, we recorded operating costs of $77 million associated with transitional reinsurance contributions for plans other than non-grandfathered individual commercial plans. In addition, for our non-grandfathered individual commercial plans we recorded ceded premiums of $25 million and recorded ceded benefits of $375 million in our condensed consolidated statements of income for the nine months ended September 30, 2014. No such amounts were recorded in 2013 as the program was not effective until January 1, 2014.
	The accompanying condensed consolidated balance sheets include the following amounts associated with the 3Rs at September 30, 2014. No such amounts were recorded in our condensed consolidated balance sheet at December 31, 2013 as the programs were not effective until January 1, 2014.
		30-Sep-14
		Risk Adjustment/Risk Corridor			Reinsurance			Reinsurance
		Settlement			Contribution			Recoverables
		(in millions)
	Current assets	$	134		$	—		$	375
	Trade accounts payable and accrued expenses	(53		)	(102		)	—
	Net current asset (liability)	$	81		$	(102	)	$	375
	We are required to remit payment for our per member reinsurance contribution in January of the year following the benefit year, or January 2015 for the 2014 benefit year. Risk adjustment calculations will be completed and HHS will notify us of recoveries due or payments owed to/from us under the risk adjustment and reinsurance programs by June 30 of the year following the benefit year. Payments due to HHS under the risk adjustment program must be remitted within 30 days of notification and will be collected prior to the distribution of recoveries by HHS. Following this notification, risk corridor calculations are then due by July 31 of the year following the benefit year. Payment and recovery amounts will be settled with HHS annually in the second half of the year following the benefit year. Accordingly, for the 2014 benefit year, we expect to receive recoveries and/or pay amounts due under these programs in the second half of 2015.
	In addition to the provisions discussed above, beginning in 2014, HHS pays us a portion of the health care costs for low-income individual members for which we assume no risk in accordance with the Health Care Reform Law. We account for these subsidies as a deposit in our consolidated balance sheets and as a financing activity in our consolidated statements of cash flows. We do not recognize premiums revenue or benefits expense for these subsidies. Receipt and payment activity is accumulated at the state and legal entity level and recorded in our consolidated balance sheets in other current assets or trade accounts payable and accrued expenses depending on the state and legal entity balance at the end of the reporting period. We will be notified of final settlement amounts by June 30 of the year following the benefit year. Receipts from HHS associated with these cost sharing subsidies for which we do not assume risk were $29 million higher than claims payments for the nine months ended September 30, 2014.

RECENTLY_ISSUED_ACCOUNTING_PRO

RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS	9 Months Ended
	Sep. 30, 2014
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]	'
RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS	'
	RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS
	In April 2014, the Financial Accounting Standards Board, or FASB, issued new guidance related to discontinued operations which changes the criteria for determining which disposals can be presented as discontinued operations and modifies related disclosure requirements. The new guidance is effective for us beginning with annual and interim periods in 2015 with early adoption permitted under certain circumstances. Based upon existing facts and circumstances, the adoption of the new guidance is not expected to have a material impact on our results of operations, financial condition, or cash flows.
	In May 2014, the FASB issued new guidance that amends the accounting for revenue recognition. The amendments are intended to provide a more robust framework for addressing revenue issues, improve comparability of revenue recognition practices, and improve disclosure requirements. Insurance contracts are not in the scope of this new guidance. Accordingly, the new guidance primarily will apply to the recognition of our services revenue, including intersegment revenues associated with our Healthcare Services segment. Services revenue represented less than 5% of our consolidated revenues for the three and nine months ended September 30, 2014. The new guidance is effective for us beginning with annual and interim periods in 2017. We are currently evaluating the impact on our results of operations, financial condition, and cash flows.
	There are no other recently issued accounting standards that apply to us or that are expected to have a material impact on our results of operations, financial condition, or cash flows.

ACQUISITIONS

ACQUISITIONS	9 Months Ended
	Sep. 30, 2014
Business Combinations [Abstract]	'
ACQUISITIONS	'
	ACQUISITIONS
	On September 6, 2013, we acquired American Eldercare Inc., or American Eldercare, the largest provider of nursing home diversion services in the state of Florida, serving frail and elderly individuals in home and community-based settings. American Eldercare complements our core capabilities and strength in serving seniors and disabled individuals with a unique focus on individualized and integrated care, and has contracts to provide Medicaid Long-Term Support Services across the entire state of Florida. The enrollment effective dates for the various regions ranged from August 2013 to March 2014. The allocation of the purchase price resulted in goodwill of $76 million and other intangible assets of $75 million. The goodwill was assigned to the Retail segment. The other intangible assets, which primarily consist of customer contracts and technology, have a weighted average useful life of 9.3 years. Goodwill and other intangible assets are amortizable as deductible expenses for tax purposes.
	The results of operations and financial condition of American Eldercare have been included in our condensed consolidated statements of income and condensed consolidated balance sheets from the acquisition dates. In addition, during 2014 and 2013, we acquired other health and wellness related businesses which, individually or in the aggregate, have not had, or are not expected to have, a material impact on our results of operations, financial condition, or cash flows. Acquisition-related costs recognized in 2014 and 2013 were not material to our results of operations. The pro forma financial information assuming the acquisitions had occurred as of the beginning of the calendar year prior to the year of acquisition, as well as the revenues and earnings generated during the year of acquisition were not material for disclosure purposes.

INVESTMENT_SECURITIES

INVESTMENT SECURITIES	9 Months Ended
	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
INVESTMENT SECURITIES	'
	INVESTMENT SECURITIES
	Investment securities classified as current and long-term were as follows at September 30, 2014 and December 31, 2013, respectively:
		Amortized			Gross			Gross			Fair
		Cost			Unrealized			Unrealized			Value
					Gains			Losses
		(in millions)
	30-Sep-14
	U.S. Treasury and other U.S. government
	corporations and agencies:
	U.S. Treasury and agency obligations	$	846		$	8		$	(2	)	$	852
	Mortgage-backed securities	1,544			42			(17		)	1,569
	Tax-exempt municipal securities	3,006			148			(3		)	3,151
	Mortgage-backed securities:
	Residential	18			—			—			18
	Commercial	698			15			(17		)	696
	Asset-backed securities	40			1			—			41
	Corporate debt securities	3,431			289			(12		)	3,708
	Total debt securities	$	9,583		$	503		$	(51	)	$	10,035
	31-Dec-13
	U.S. Treasury and other U.S. government
	corporations and agencies:
	U.S. Treasury and agency obligations	$	584		$	6		$	(6	)	$	584
	Mortgage-backed securities	1,834			34			(48		)	1,820
	Tax-exempt municipal securities	2,911			93			(33		)	2,971
	Mortgage-backed securities:
	Residential	22			—			—			22
	Commercial	662			20			(9		)	673
	Asset-backed securities	63			1			(1		)	63
	Corporate debt securities	3,474			223			(30		)	3,667
	Total debt securities	$	9,550		$	377		$	(127	)	$	9,800
	Gross unrealized losses and fair values aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position were as follows at September 30, 2014 and December 31, 2013, respectively:
		Less than 12 months						12 months or more						Total
		Fair			Gross			Fair			Gross			Fair		Gross
		Value			Unrealized			Value			Unrealized			Value		Unrealized
					Losses						Losses					Losses
		(in millions)
	30-Sep-14
	U.S. Treasury and other U.S.
	government corporations
	and agencies:
	U.S. Treasury and agency	$	59		$	—		$	86		$	(2	)	$	145	$	(2	)
	obligations
	Mortgage-backed	147			(1		)	475			(16		)	622		(17		)
	securities
	Tax-exempt municipal	136			—			136			(3		)	272		(3		)
	securities
	Mortgage-backed securities:
	Residential	1			—			4			—			5		—
	Commercial	145			(3		)	206			(14		)	351		(17		)
	Asset-backed securities	—			—			16			—			16		—
	Corporate debt securities	209			(3		)	141			(9		)	350		(12		)
	Total debt securities	$	697		$	(7	)	$	1,064		$	(44	)	$	1,761	$	(51	)
	31-Dec-13
	U.S. Treasury and other U.S.
	government corporations
	and agencies:
	U.S. Treasury and agency	$	231		$	(6	)	$	5		$	—		$	236	$	(6	)
	obligations
	Mortgage-backed	1,076			(47		)	21			(1		)	1,097		(48		)
	securities
	Tax-exempt municipal	693			(28		)	57			(5		)	750		(33		)
	securities
	Mortgage-backed securities:
Residential	6			—			1			—			7		—
Commercial	270			(8		)	40			(1		)	310		(9		)
Asset-backed securities	35			(1		)	—			—			35		(1		)
Corporate debt securities	594			(28		)	17			(2		)	611		(30		)
Total debt securities	$	2,905		$	(118	)	$	141		$	(9	)	$	3,046	$	(127	)
Approximately 96% of our debt securities were investment-grade quality, with a weighted average credit rating of AA- by S&P at September 30, 2014. Most of the debt securities that were below investment-grade were rated BB, the higher end of the below investment-grade rating scale. At September 30, 2014, 5% of our tax-exempt municipal securities were pre-refunded, generally with U.S. government and agency securities. Tax-exempt municipal securities that were not pre-refunded were diversified among general obligation bonds of U.S. states and local municipalities as well as special revenue bonds. General obligation bonds, which are backed by the taxing power and full faith of the issuer, accounted for 39% of the tax-exempt municipals that were not pre-refunded in the portfolio. Special revenue bonds, issued by a municipality to finance a specific public works project such as utilities, water and sewer, transportation, or education, and supported by the revenues of that project, accounted for the remaining 61% of these municipals. Our general obligation bonds are diversified across the United States with no individual state exceeding 11%. In addition, 16% of our tax-exempt securities were insured by bond insurers and had an equivalent weighted average S&P credit rating of AA exclusive of the bond insurers’ guarantee. Our investment policy limits investments in a single issuer and requires diversification among various asset types.
The recoverability of our non-agency residential and commercial mortgage-backed securities is supported by factors such as seniority, underlying collateral characteristics and credit enhancements. These residential and commercial mortgage-backed securities at September 30, 2014 primarily were composed of senior tranches having high credit support, with over 99% of the collateral consisting of prime loans. The weighted average credit rating of all commercial mortgage-backed securities was AA at September 30, 2014.
The percentage of corporate securities associated with the financial services industry was 20% at September 30, 2014 and 23% at December 31, 2013.
All issuers of securities we own that were trading at an unrealized loss at September 30, 2014 remain current on all contractual payments. After taking into account these and other factors previously described, we believe these unrealized losses primarily were caused by an increase in market interest rates since the time the securities were purchased. At September 30, 2014, we did not intend to sell the securities with an unrealized loss position in accumulated other comprehensive income, and it is not likely that we will be required to sell these securities before recovery of their amortized cost basis. As a result, we believe that the securities with an unrealized loss were not other-than-temporarily impaired at September 30, 2014.
The detail of realized gains (losses) related to investment securities and included within investment income was as follows for the three and nine months ended September 30, 2014 and 2013:
	Three months ended						Nine months ended
	September 30,						September 30,
	2014			2013			2014			2013
	(in millions)
Gross realized gains	$	7		$	7		$	14		$	24
Gross realized losses	(1		)	(3		)	(5		)	(10		)
Net realized capital gains	$	6		$	4		$	9		$	14
There were no material other-than-temporary impairments for the three and nine months ended September 30, 2014 or 2013.
The contractual maturities of debt securities available for sale at September 30, 2014, regardless of their balance sheet classification, are shown below. Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.
	Amortized			Fair
	Cost			Value
	(in millions)
Due within one year	$	1,030		$	1,036
Due after one year through five years	2,119			2,234
Due after five years through ten years	2,184			2,307
Due after ten years	1,950			2,134
Mortgage and asset-backed securities	2,300			2,324
Total debt securities	$	9,583		$	10,035

FAIR_VALUE

FAIR VALUE	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
FAIR VALUE	'
	FAIR VALUE
	Financial Assets
	The following table summarizes our fair value measurements at September 30, 2014 and December 31, 2013, respectively, for financial assets measured at fair value on a recurring basis:
		Fair Value Measurements Using
		Fair		Quoted Prices		Other		Unobservable
		Value		in Active		Observable		Inputs
				Markets		Inputs		(Level 3)
				(Level 1)		(Level 2)
		(in millions)
	30-Sep-14
	Cash equivalents	$	2,606	$	2,606	$	—	$	—
	Debt securities:
	U.S. Treasury and other U.S. government
	corporations and agencies:
	U.S. Treasury and agency obligations	852		—		852		—
	Mortgage-backed securities	1,569		—		1,569		—
	Tax-exempt municipal securities	3,151		—		3,138		13
	Mortgage-backed securities:
	Residential	18		—		18		—
	Commercial	696		—		696		—
	Asset-backed securities	41		—		40		1
	Corporate debt securities	3,708		—		3,684		24
	Total debt securities	10,035		—		9,997		38
	Total invested assets	$	12,641	$	2,606	$	9,997	$	38
	31-Dec-13
	Cash equivalents	$	876	$	876	$	—	$	—
	Debt securities:
	U.S. Treasury and other U.S. government
	corporations and agencies:
	U.S. Treasury and agency obligations	584		—		584		—
	Mortgage-backed securities	1,820		—		1,820		—
	Tax-exempt municipal securities	2,971		—		2,958		13
	Mortgage-backed securities:
	Residential	22		—		22		—
	Commercial	673		—		673		—
	Asset-backed securities	63		—		62		1
	Corporate debt securities	3,667		—		3,644		23
	Total debt securities	9,800		—		9,763		37
	Total invested assets	$	10,676	$	876	$	9,763	$	37
	There were no material transfers between Level 1 and Level 2 during the three and nine months ended September 30, 2014 or September 30, 2013.
	Our Level 3 assets had a fair value of $38 million at September 30, 2014, or 0.3% of our total invested assets. During the three and nine months ended September 30, 2014 and 2013, the changes in the fair value of the assets measured using significant unobservable inputs (Level 3) were comprised of the following:
		For the three months ended September 30,
		2014						2013
		Private		Auction		Total		Private			Auction		Total
		Placements		Rate				Placements			Rate
				Securities							Securities
		(in millions)
	Beginning balance at April 1	$	24	$	13	$	37	$	23		$	13	$	36
	Total gains or losses:
	Realized in earnings	—		—		—		—			—		—
	Unrealized in other	1		—		1		1			—		1
	comprehensive income
	Purchases	—		—		—		—			—		—
	Sales	—		—		—		—			—		—
	Settlements	—		—		—		—			—		—
	Balance at September 30	$	25	$	13	$	38	$	24		$	13	$	37
		For the nine months ended September 30,
		2014						2013
		Private		Auction		Total		Private			Auction		Total
		Placements		Rate				Placements			Rate
				Securities							Securities
		(in millions)
	Beginning balance at January 1	$	24	$	13	$	37	$	25		$	13	$	38
Total gains or losses:
Realized in earnings	—		—		—		—			—		—
Unrealized in other	1		—		1		—			—		—
comprehensive income
Purchases	—		—		—		—			—		—
Sales	—		—		—		—			—		—
Settlements	—		—		—		(1		)	—		(1		)
Balance at September 30	$	25	$	13	$	38	$	24		$	13	$	37
Financial Liabilities
Our long-term debt is recorded at carrying value in our consolidated balance sheets. The carrying value of our long-term debt outstanding, including the current portion, was $4,338 million at September 30, 2014 and $2,600 million at December 31, 2013. The fair value of our long-term debt, including the current portion, was $4,565 million at September 30, 2014 and $2,751 million at December 31, 2013. The fair value of our long-term debt is determined based on Level 2 inputs, including quoted market prices for the same or similar debt, or if no quoted market prices are available, on the current prices estimated to be available to us for debt with similar terms and remaining maturities.
Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis
As disclosed in Note 3, the acquisitions of American Eldercare and other health and wellness companies were completed during 2014 and 2013. The values of net tangible assets acquired and the resulting goodwill and other intangible assets were recorded at fair value using Level 3 inputs. The majority of the related tangible assets acquired and liabilities assumed were recorded at their carrying values as of the respective dates of acquisition, as their carrying values approximated their fair values due to their short-term nature. The fair values of goodwill and other intangible assets acquired in these acquisitions were internally estimated primarily based on the income approach. The income approach estimates fair value based on the present value of the cash flows that the assets are expected to generate in the future. We developed internal estimates for the expected cash flows and discount rates used in the present value calculations. Other than assets acquired and liabilities assumed in these acquisitions, there were no material assets or liabilities measured at fair value on a nonrecurring basis during the three and nine months ended September 30, 2014 or 2013.

MEDICARE_PART_D

MEDICARE PART D	9 Months Ended
	Sep. 30, 2014
Insurance [Abstract]	'
MEDICARE PART D	'
	MEDICARE PART D
	We cover prescription drug benefits in accordance with Medicare Part D under multiple contracts with the Centers for Medicare and Medicaid Services, or CMS. The accompanying condensed consolidated balance sheets include the following amounts associated with Medicare Part D at September 30, 2014 and December 31, 2013. Amounts included below relating to the 2013 contract year for the net risk corridor payable of $35 million and the CMS subsidies receivable of $691 million at September 30, 2014 were settled in October 2014.
		30-Sep-14						31-Dec-13
		Risk			CMS			Risk			CMS
		Corridor			Subsidies/			Corridor			Subsidies/
		Settlement			Discounts			Settlement			Discounts
		(in millions)
	Other current assets	$	205		$	1,517		$	45		$	743
	Trade accounts payable and accrued expenses	(80		)	(43		)	(71		)	(30		)
	Net current (liability) asset	125			1,474			(26		)	713

GOODWILL_AND_OTHER_INTANGIBLE_

GOODWILL AND OTHER INTANGIBLE ASSETS	9 Months Ended
	Sep. 30, 2014
Goodwill and Intangible Assets Disclosure [Abstract]	'
GOODWILL AND OTHER INTANGIBLE ASSETS	'
	GOODWILL AND OTHER INTANGIBLE ASSETS
	The carrying amount of goodwill for our reportable segments has been retrospectively adjusted to conform to the 2014 presentation as discussed in Note 1. Changes in the carrying amount of goodwill for our reportable segments for the nine months ended September 30, 2014 were as follows:
		Retail				Employer				Healthcare				Other				Total
						Group				Services				Businesses
		(in millions)
	Balance at January 1, 2014	$	1,007			$	363			$	2,271			$	92			$	3,733
	Acquisitions	—				—				3				—				3
	Dispositions	—				—				(40		)		—				(40		)
	Subsequent payments/adjustments	—				—				(1		)		—				(1		)
	Balance at September 30, 2014	$	1,007			$	363			$	2,233			$	92			$	3,695
	The following table presents details of our other intangible assets included in other long-term assets in the accompanying condensed consolidated balance sheets at September 30, 2014 and December 31, 2013:
				30-Sep-14												31-Dec-13
		Weighted		Cost				Accumulated				Net				Cost				Accumulated		Net
		Average						Amortization												Amortization
		Life
		(in millions)
	Other intangible assets:
	Customer contracts/	9.8 yrs		$	764			$	349			$	415			$	792			$	310	$	482
	relationships
	Trade names and	13.2 yrs		198				54				144				200				40		160
	technology
	Provider contracts	15.1 yrs		51				19				32				51				23		28
	Noncompetes and	6.6 yrs		50				34				16				52				29		23
	other
	Total other intangible	10.5 yrs		$	1,063			$	456			$	607			$	1,095			$	402	$	693
	assets
	Amortization expense for other intangible assets was approximately $28 million for the three months ended September 30, 2014 and 2013. For the nine months ended September 30, 2014 and 2013, amortization expense for other intangible assets was approximately $85 million and $84 million, respectively. The following table presents our estimate of amortization expense for 2014 and each of the five next succeeding years:
		(in millions)
	For the years ending December 31,:
	2014	$	112
	2015	101
	2016	94
	2017	86
	2018	79
	2019	67

EARNINGS_PER_COMMON_SHARE_COMP

EARNINGS PER COMMON SHARE COMPUTATION	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
EARNINGS PER COMMON SHARE COMPUTATION	'
	EARNINGS PER COMMON SHARE COMPUTATION
	Detail supporting the computation of basic and diluted earnings per common share was as follows for the three and nine months ended September 30, 2014 and 2013:
		Three months ended September 30,				Nine months ended September 30,
		2014		2013		2014		2013
		(dollars in millions, except per common share results; number of shares in thousands)
	Net income available for common stockholders	$	290	$	368	$	1,002	$	1,261
	Weighted average outstanding shares of common stock	154,502		157,187		155,006		158,026
	used to compute basic earnings per common share
	Dilutive effect of:
	Employee stock options	203		289		233		341
	Restricted stock	1,525		1,431		1,402		1,244
	Shares used to compute diluted earnings per common share	156,230		158,907		156,641		159,611
	Basic earnings per common share	$	1.87	$	2.34	$	6.46	$	7.98
	Diluted earnings per common share	$	1.85	$	2.31	$	6.39	$	7.9
	Number of antidilutive stock options and restricted stock	43		202		420		910
	excluded from computation

STOCKHOLDERS_EQUITY

STOCKHOLDERS' EQUITY	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
STOCKHOLDERS' EQUITY	'
	STOCKHOLDERS’ EQUITY
	Dividends
	The following table provides details of dividend payments in 2013 and 2014 under our Board approved quarterly cash dividend policy:
	Record	Payment	Amount		Total
	Date	Date	per Share		Amount
					(in millions)
	2013 payments
	12/31/12	1/25/13	$	0.26	$	42
	3/28/13	4/26/13	$	0.26	$	41
	6/28/13	7/26/13	$	0.27	$	42
	9/30/13	10/25/13	$	0.27	$	42
	2014 payments
	12/31/13	1/31/14	$	0.27	$	42
	3/31/14	4/25/14	$	0.27	$	42
	6/30/14	7/25/14	$	0.28	$	43
	9/30/14	10/31/14	$	0.28	$	43
	In October 2014, the Board declared a cash dividend of $0.28 per share payable on January 30, 2015 to stockholders of record on December 31, 2014. Declaration and payment of future quarterly dividends is at the discretion of the Board and may be adjusted as business needs or market conditions change.
	Stock Repurchases
	In September 2014, the Board of Directors replaced a previous share repurchase authorization of up to $1 billion (of which $816 million remained unused) with a new authorization for repurchases of up to $2 billion of our common shares exclusive of shares repurchased in connection with employee stock plans, expiring on December 31, 2016. Under the new share repurchase authorization, shares may be purchased from time to time at prevailing prices in the open market, by block purchases, or in privately-negotiated transactions, subject to certain regulatory restrictions on volume, pricing, and timing. During the nine months ended September 30, 2014, we repurchased 1.60 million shares in open market transactions for $195 million at an average price of $121.68 under previous share repurchase authorizations and we repurchased 0.27 million shares in open market transactions for $35 million at an average price of $128.34 under the current authorization. During the nine months ended September 30, 2013, we repurchased 3.78 million shares in open market transactions for $301 million at an average price of $79.79 under previous share repurchase authorizations. During the period commencing on October 1, 2014 and ending on November 6, 2014, we repurchased 0.77 million shares in open market transactions for $100 million at an average price of $130.50 under the current authorization. As of November 7, 2014, the remaining authorized amount under the new authorization totaled $1.87 billion.
	In connection with employee stock plans, we acquired 0.4 million common shares for $40 million and 0.3 million common shares for $24 million during the nine months ended September 30, 2014 and 2013, respectively.
	Accumulated Other Comprehensive Income
	Accumulated other comprehensive income included net unrealized gains on our investment securities of $286 million at September 30, 2014 and $158 million at December 31, 2013. In addition, accumulated other comprehensive income included $53 million at September 30, 2014 for an additional liability that would exist on our closed block of long-term care insurance policies if unrealized gains on the sale of the investments backing such products had been realized and the proceeds reinvested at then current yields. There was no such additional liability at December 31, 2013. Refer to Note 17 to the consolidated financial statements in our 2013 Form 10-K for further discussion of our long-term care insurance policies.

INCOME_TAXES

INCOME TAXES	9 Months Ended
	Sep. 30, 2014
Income Tax Disclosure [Abstract]	'
INCOME TAXES	'
	INCOME TAXES
	The effective income tax rate was 47.5% for the three months ended September 30, 2014, compared to 37.2% for the three months ended September 30, 2013. For the nine months ended September 30, 2014 the effective tax rate was 46.8%, compared to 36.0% for the nine months ended September 30, 2013. The non-deductible nature of the health insurance industry fee levied on the industry beginning in 2014 as mandated by the Health Care Reform Law increased our effective tax rate by approximately 10 percentage points for the nine months ended September 30, 2014. In addition, the effective tax for the three and nine months ended September 30, 2013 includes the beneficial effect of a change in our estimated tax liability associated with limitations on the deductibility of annual compensation in excess of $500,000 per employee as mandated by the Health Care Reform Law.

DEBT

DEBT	9 Months Ended
	Sep. 30, 2014
Debt Disclosure [Abstract]	'
DEBT	'
	DEBT
	The carrying value of long-term debt outstanding, including the current portion, was as follows at September 30, 2014 and December 31, 2013:
		September 30, 2014		December 31, 2013
		(in millions)
	Senior notes:
	$500 million, 6.45% due June 1, 2016	$	512	$	517
	$500 million, 7.20% due June 15, 2018	505		505
	$300 million, 6.30% due August 1, 2018	312		314
	$400 million, 2.625% due October 1, 2019	400		—
	$600 million, 3.15% due December 1, 2022	598		598
	$600 million, 3.85% due October 1, 2024	599		—
	$250 million, 8.15% due June 15, 2038	266		266
	$400 million, 4.625% due December 1, 2042	400		400
	$750 million, 4.95% due October 1, 2044	746		—
	Total debt	$	4,338	$	2,600
	Less current portion of long-term debt	512		—
	Total long-term debt	$	3,826	$	2,600
	Senior Notes
	In September 2014, we issued $400 million of 2.625% senior notes due October 1, 2019, $600 million of 3.85% senior notes due October 1, 2024 and $750 million of 4.95% senior notes due October 1, 2044. Our net proceeds, reduced for the underwriters' discount and commission and offering expenses, were $1.73 billion. We used a portion of the net proceeds to redeem the 6.45% senior unsecured notes as discussed below, and intend to use some or all of the remaining net proceeds to repurchase shares of our common stock and for general corporate purposes.
	In October 2014, we redeemed the $500 million 6.45% senior unsecured notes due June 1, 2016, at 100% of the principal amount plus applicable premium for early redemption and accrued and unpaid interest to the redemption date, for cash totaling approximately $560 million. We recognized a loss on extinguishment of debt of approximately $37 million in October 2014 for the redemption of these notes.
	Our senior notes, which are unsecured, may be redeemed at our option at any time at 100% of the principal amount plus accrued interest and a specified make-whole amount. The 7.20% and 8.15% senior notes are subject to an interest rate adjustment if the debt ratings assigned to the notes are downgraded (or subsequently upgraded). In addition, our senior notes (other than the 6.30% senior notes) contain a change of control provision that may require us to purchase the notes under certain circumstances.
	Prior to 2009, we were parties to interest-rate swap agreements that exchanged the fixed interest rate under our senior notes for a variable interest rate based on LIBOR. As a result, the carrying value of the senior notes was adjusted to reflect changes in value caused by an increase or decrease in interest rates. During 2008, we terminated all of our swap agreements. The cumulative adjustment to the carrying value of our senior notes was $103 million as of the termination date which is being amortized as a reduction to interest expense over the remaining term of the senior notes. The unamortized carrying value adjustment was $45 million as of September 30, 2014 and $54 million as of December 31, 2013. In October 2014, the redemption of our 6.45% senior notes reduced the unamortized carrying value adjustment by $12 million.
	Credit Agreement
	Our 5-year $1.0 billion unsecured revolving credit agreement expires July 2018. Under the credit agreement, at our option, we can borrow on either a competitive advance basis or a revolving credit basis. The revolving credit portion bears interest at either LIBOR plus a spread or the base rate plus a spread. The LIBOR spread, currently 110 basis points, varies depending on our credit ratings ranging from 90.0 to 150.0 basis points. We also pay an annual facility fee regardless of utilization. This facility fee, currently 15 basis points, may fluctuate between 10.0 and 25.0 basis points, depending upon our credit ratings. The competitive advance portion of any borrowings will bear interest at market rates prevailing at the time of borrowing on either a fixed rate or a floating rate based on LIBOR, at our option.
	The terms of the credit agreement include standard provisions related to conditions of borrowing, including a customary material adverse effect clause which could limit our ability to borrow additional funds. In addition, the credit agreement contains customary restrictive and financial covenants as well as customary events of default, including financial covenants regarding the maintenance of a minimum level of net worth of $7.6 billion at September 30, 2014 and a maximum leverage ratio of 3.0:1. We are in compliance with the financial covenants, with actual net worth of $10.1 billion and an actual leverage ratio of 1.8:1, as measured in accordance with the credit agreement as of September 30, 2014. In addition, the credit agreement includes an uncommitted $250 million incremental loan facility.
	At September 30, 2014, we had no borrowings outstanding under the credit agreement and we had outstanding letters of credit of $5 million secured under that credit agreement. No amounts have been drawn on these letters of credit. Accordingly, as of September 30, 2014, we had $995 million of remaining borrowing capacity under the credit agreement, none of which would be restricted by our financial covenant compliance requirement. We have other customary, arms-length relationships, including financial advisory and banking, with some parties to the credit agreement.
	Commercial Paper
	In October 2014, we entered into a commercial paper program pursuant to which we may issue short-term, unsecured commercial paper notes privately placed on a discount basis through certain broker dealers. Amounts available under the program may be borrowed, repaid and re-borrowed from time to time, with the aggregate face or principal amounts outstanding under the program at any time not to exceed $1 billion. The net proceeds of issuances are expected to be used for general corporate purposes, including to repurchase shares of our common stock. As of November 6, 2014, we had $150 million outstanding in our commercial paper program.

GUARANTEES_AND_CONTINGENCIES

GUARANTEES AND CONTINGENCIES	9 Months Ended
	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
GUARANTEES AND CONTINGENCIES	'
	GUARANTEES AND CONTINGENCIES
	Government Contracts
	Our Medicare products, which accounted for approximately 73% of our total premiums and services revenue for the nine months ended September 30, 2014, primarily consisted of products covered under the Medicare Advantage and Medicare Part D Prescription Drug Plan contracts with the federal government. These contracts are renewed generally for a calendar year term unless CMS notifies us of its decision not to renew by May 1 of the calendar year in which the contract would end, or we notify CMS of our decision not to renew by the first Monday in June of the calendar year in which the contract would end. All material contracts between Humana and CMS relating to our Medicare products have been renewed for 2015, and all of our product offerings filed with CMS for 2015 have been approved.
	CMS uses a risk-adjustment model which apportions premiums paid to Medicare Advantage plans according to health severity of covered members. The risk-adjustment model pays more for enrollees with predictably higher costs. Under this model, rates paid to Medicare Advantage plans are based on actuarially determined bids, which include a process whereby our prospective payments are based on a comparison of our beneficiaries’ risk scores, derived from medical diagnoses, to those enrolled in the government’s original Medicare program. Under the risk-adjustment methodology, all Medicare Advantage plans must collect and submit the necessary diagnosis code information from hospital inpatient, hospital outpatient, and physician providers to CMS within prescribed deadlines. The CMS risk-adjustment model uses the diagnosis data to calculate the risk-adjusted premium payment to Medicare Advantage plans, which CMS adjusts for coding pattern differences between the health plans and the government fee-for-service program. We generally rely on providers, including certain providers in our network who are our employees, to code their claim submissions with appropriate diagnoses, which we send to CMS as the basis for our payment received from CMS under the actuarial risk-adjustment model. We also rely on these providers to document appropriately all medical data, including the diagnosis data submitted with claims. In addition, we conduct medical record reviews as part of our data and payment accuracy compliance efforts, to more accurately reflect diagnosis conditions under the risk adjustment model. These compliance efforts include the internal contract level audits described in more detail below.
	CMS is continuing to perform audits of various companies’ selected Medicare Advantage contracts related to this risk adjustment diagnosis data. We refer to these audits as Risk-Adjustment Data Validation Audits, or RADV audits. RADV audits review medical records in an attempt to validate provider medical record documentation and coding practices which influence the calculation of premium payments to Medicare Advantage plans.
	In 2012, CMS released a “Notice of Final Payment Error Calculation Methodology for Part C Medicare Advantage Risk Adjustment Data Validation (RADV) Contract-Level Audits.” The payment error calculation methodology provides that, in calculating the economic impact of audit results for a Medicare Advantage contract, if any, the results of the audit sample will be extrapolated to the entire Medicare Advantage contract based upon a comparison to “benchmark” audit data in the government fee-for-service program. This comparison to the government program benchmark audit is necessary to determine the economic impact, if any, of audit results because the government program data set, including any attendant errors that are present in that data set, provides the basis for Medicare Advantage plans’ risk adjustment to payment rates. CMS already makes other adjustments to payment rates based on a comparison of coding pattern differences between Medicare Advantage plans and the government fee-for-service program data (such as for frequency of coding for certain diagnoses in Medicare Advantage plan data versus the government program data set).
	The final methodology, including the first application of extrapolated audit results to determine audit settlements, is expected to be applied to the current round of RADV contract level audits being conducted on 2011 premium payments. Selected Medicare Advantage contracts will be notified of an audit at some point after the close of the final reconciliation for the payment year being audited. The final reconciliation occurs in August of the calendar year following the payment year. On November 5, 2013, we were notified that certain of our Medicare Advantage contracts have been selected for audit for contract year 2011.
	Estimated audit settlements are recorded as a reduction of premiums revenue in our consolidated statements of income, based upon available information. We perform internal contract level audits based on the RADV audit methodology prescribed by CMS. Included in these internal contract level audits is an audit of our Private Fee-For-Service business which we used to represent a proxy of the benchmark audit data in the government fee-for-service program which has not yet been released. We based our accrual of estimated audit settlements for contract years 2011 (the first year that application of extrapolated audit results is applicable) through 2014 on the results of these internal contract level audits and update our estimates as each audit is completed. Estimates derived from these results were not material to our results of operations, financial position, or cash flows. However, as indicated, we are awaiting additional guidance from CMS regarding the benchmark audit data in the government fee-for-service program. Accordingly, we cannot determine whether such RADV audits will have a material adverse effect on our results of operations, financial position, or cash flows.
	In addition, CMS' recent comments in formalized guidance regarding “overpayments” to Medicare Advantage plans appear to be inconsistent with the Agency’s prior RADV audit guidance. These statements, contained in the preamble to CMS’ final rule release regarding Medicare Advantage and Part D prescription drug benefit program regulations for Contract Year 2015, appear to equate each Medicare Advantage risk adjustment data error with an “overpayment” without reconciliation to the principles underlying the FFS Adjuster referenced above. We will continue to work with CMS to ensure that Medicare Advantage plans are paid accurately and that payment model principles are in accordance with the requirements of the Social Security Act, which, if not implemented correctly could have a material adverse effect on our results of operations, financial position, or cash flows.
	At September 30, 2014, our military services business, which accounted for approximately 1% of our total premiums and services revenue for the nine months ended September 30, 2014, primarily consisted of the TRICARE South Region contract. The current 5-year South Region contract, which expires March 31, 2017, is subject to annual renewals on April 1 of each year during its term at the government’s option. On March 14, 2014, the Defense Health Agency, or DHA, exercised its option to extend the TRICARE South Region contract through March 31, 2015.
	The loss of any of the contracts above or significant changes in these programs as a result of legislative or regulatory action, including reductions in premium payments to us, regulatory restrictions on profitability, including by comparison of our Medicare Advantage profitability to our non-Medicare Advantage business profitability and a requirement that they remain within certain ranges of each other, or increases in member benefits without corresponding increases in premium payments to us, may have a material adverse effect on our results of operations, financial position, and cash flows.
	Our state-based Medicaid business accounted for approximately 2% of our total premiums and services revenue for the nine months ended September 30, 2014. In addition to our state-based Medicaid contracts in Florida and Kentucky, we have contracts in Illinois and Virginia for stand-alone dual eligible demonstration programs serving individuals dually eligible for both the federal Medicare program and the applicable state-based Medicaid program. We began serving members in Illinois in the first quarter of 2014 and in Virginia in the second quarter of 2014. In addition, we began serving members in Long-Term Care Support Services (LTSS) regions in Florida at various effective dates ranging from the second half of 2013 through the first quarter of 2014.
	On June 26, 2013, the Puerto Rico Health Insurance Administration notified us of its election not to renew our three-year Medicaid contracts for the East, Southeast, and Southwest regions which ended June 30, 2013. Contractual transition provisions required the continuation of insurance coverage for beneficiaries through September 30, 2013 and also required an additional period of time thereafter to process residual claims.
	Legal Proceedings and Certain Regulatory Matters
	Florida Matters
	On December 16, 2010, an individual filed a qui tam suit captioned United States of America ex rel. Marc Osheroff v. Humana et al. in the Southern District of Florida, against us, several of our health plan subsidiaries, and certain other companies that operate medical centers in Miami-Dade County, Florida. After the U.S. government declined to intervene, the Court ordered the complaint unsealed, and the individual plaintiff amended his complaint and served the Company on December 8, 2011. The amended complaint alleges certain civil violations by our CAC Medical Centers in Florida, including offering various amenities such as transportation and meals, to Medicare and dual eligible individuals in our community center settings. The amended complaint also alleges civil violations by our Medicare Advantage health plans in Florida, arising from the alleged activities of our CAC Medical Centers and the codefendants in the complaint. The amended complaint seeks damages and penalties on behalf of the United States under the Anti-Inducement and Anti-Kickback Statutes and the False Claims Act. On September 28, 2012, the Court dismissed, with prejudice, all causes of action that were asserted in the suit. On November 19, 2013, the individual plaintiff appealed the dismissal of the complaint, and we are awaiting the decision of the Court on the appeal.
	On January 6, 2012, the Civil Division of the United States Attorney’s Office for the Southern District of Florida advised us that it is seeking documents and information from us and several of our affiliates relating to several matters including the coding of medical claims by one or more South Florida medical providers, and loans to physician practices. On May 1, 2014, the U.S. government filed a Notice of Non-Intervention in connection with a civil qui tam suit related to one of these matters captioned United States of America ex rel. Olivia Graves v. Plaza Medical Centers, et al., and the Court ordered the complaint unsealed. Subsequently, the individual plaintiff amended the complaint and served the Company, opting to continue to pursue the action. On October 7, 2014 the Court dismissed the complaint and granted leave to amend. The individual plaintiff filed a second amended complaint on October 23, 2014. We continue to cooperate with and respond to information requests from the U.S. Attorney’s office. These matters could result in additional qui tam litigation.
	Other Lawsuits and Regulatory Matters
	Our current and past business practices are subject to review or other investigations by various state insurance and health care regulatory authorities and other state and federal regulatory authorities. These authorities regularly scrutinize the business practices of health insurance and benefits companies. These reviews focus on numerous facets of our business, including claims payment practices, provider contracting, risk adjustment, competitive practices, commission payments, privacy issues, utilization management practices, pharmacy benefits, access to care, and sales practices, among others. Some of these reviews have historically resulted in fines imposed on us and some have required changes to some of our practices. We continue to be subject to these reviews, which could result in additional fines or other sanctions being imposed on us or additional changes in some of our practices.
	We also are involved in various other lawsuits that arise, for the most part, in the ordinary course of our business operations, certain of which may be styled as class-action lawsuits. Among other matters, this litigation may include employment matters, claims of medical malpractice, bad faith, nonacceptance or termination of providers, anticompetitive practices, improper rate setting, provider contract rate disputes, failure to disclose network discounts and various other provider arrangements, general contractual matters, intellectual property matters, and challenges to subrogation practices. For example, a number of hospitals and other providers have asserted that, under their network provider contracts, we are not entitled to reduce Medicare Advantage payments to these providers in connection with changes in Medicare payment systems and in accordance with the Balanced Budget and Emergency Deficit Control Act of 1985, as amended (commonly referred to as “sequestration”). Those challenges have led and could lead to arbitration demands or other litigation. Also, under state guaranty assessment laws, we may be assessed (up to prescribed limits) for certain obligations to the policyholders and claimants of insolvent insurance companies that write the same line or lines of business as we do.
	As a government contractor, we may also be subject to qui tam litigation brought by individuals who seek to sue on behalf of the government, alleging that the government contractor submitted false claims to the government including, among other allegations, those resulting from coding and review practices under the Medicare risk adjustment model. Qui tam litigation is filed under seal to allow the government an opportunity to investigate and to decide if it wishes to intervene and assume control of the litigation. If the government does not intervene, the lawsuit is unsealed, and the individual may continue to prosecute the action on his or her own, on behalf of the government. We also are subject to other allegations of non-performance of contractual obligations to providers, members, and others, including failure to properly pay claims, improper policy terminations, challenges to our implementation of the Medicare Part D prescription drug program and other litigation.
	A limited number of the claims asserted against us are subject to insurance coverage. Personal injury claims, claims for extracontractual damages, care delivery malpractice, and claims arising from medical benefit denials are covered by insurance from our wholly owned captive insurance subsidiary and excess carriers, except to the extent that claimants seek punitive damages, which may not be covered by insurance in certain states in which insurance coverage for punitive damages is not permitted. In addition, insurance coverage for all or certain forms of liability has become increasingly costly and may become unavailable or prohibitively expensive in the future.
	We record accruals for the contingencies discussed above to the extent that we conclude it is probable that a liability has been incurred and the amount of the loss can be reasonably estimated. No estimate of the possible loss or range of loss in excess of amounts accrued, if any, can be made at this time regarding the matters specifically described above because of the inherently unpredictable nature of legal proceedings, which also may be exacerbated by various factors, including: (i) the damages sought in the proceedings are unsubstantiated or indeterminate; (ii) discovery is not complete; (iii) the proceeding is in its early stages; (iv) the matters present legal uncertainties; (v) there are significant facts in dispute; (vi) there are a large number of parties (including where it is uncertain how liability, if any, will be shared among multiple defendants); or (vii) there is a wide range of potential outcomes.
	The outcome of any current or future litigation or governmental or internal investigations, including the matters described above, cannot be accurately predicted, nor can we predict any resulting penalties, fines or other sanctions that may be imposed at the discretion of federal or state regulatory authorities. Nevertheless, it is reasonably possible that any such outcome of litigation, penalties, fines or other sanctions could be substantial, and the outcome of these matters may have a material adverse effect on our results of operations, financial position, and cash flows, and may also affect our reputation.

SEGMENT_INFORMATION

SEGMENT INFORMATION	9 Months Ended
	Sep. 30, 2014
Segment Reporting [Abstract]	'
SEGMENT INFORMATION	'
	SEGMENT INFORMATION
	We manage our business with three reportable segments: Retail, Employer Group, and Healthcare Services. In addition, the Other Businesses category includes businesses that are not individually reportable because they do not meet the quantitative thresholds required by generally accepted accounting principles. These segments are based on a combination of the type of health plan customer and adjacent businesses centered on well-being solutions for our health plans and other customers, as described below. These segment groupings are consistent with information used by our Chief Executive Officer to assess performance and allocate resources.
	The Retail segment consists of Medicare and commercial fully-insured medical and specialty health insurance benefits, including dental, vision, and other supplemental health and financial protection products, marketed directly to individuals, and includes our contract with CMS to administer the Limited Income Newly Eligible Transition, or LI-NET, prescription drug plan program and contracts with various states to provide Medicaid, dual eligible, and Long-Term Support Services benefits, collectively our state-based contracts. The Employer Group segment consists of Medicare and commercial fully-insured medical and specialty health insurance benefits, including dental, vision, and voluntary benefit products, as well as administrative services only, or ASO, products and our health and wellness products primarily marketed to employer groups. The Healthcare Services segment includes services offered to our health plan members as well as to third parties including pharmacy, provider services, home based services, integrated behavioral health services and predictive modeling and informatics services. The Other Businesses category consists of our military services, primarily our TRICARE South Region contract, closed-block of long-term care insurance policies, and our Puerto Rico Medicaid contracts under which coverage was terminated effective September 30, 2013.
	Our Healthcare Services intersegment revenues primarily relate to managing prescription drug coverage for members of our other segments through Humana Pharmacy Solutions®, or HPS, and includes the operations of RightSourceRx®, our mail order pharmacy business. These revenues consist of the prescription price (ingredient cost plus dispensing fee), including the portion to be settled with the member (co-share) or with the government (subsidies), plus any associated administrative fees. Services revenues related to the distribution of prescriptions by third party retail pharmacies in our networks are recognized when the claim is processed and product revenues from dispensing prescriptions from our mail order pharmacies are recorded when the prescription or product is shipped. Our pharmacy operations, which are responsible for designing pharmacy benefits, including defining member co-share responsibilities, determining formulary listings, contracting with retail pharmacies, confirming member eligibility, reviewing drug utilization, and processing claims, act as a principal in the arrangement on behalf of members in our other segments. As principal, our Healthcare Services segment reports revenues on a gross basis including co-share amounts from members collected by third party retail pharmacies at the point of service.
	In addition, our Healthcare Services intersegment revenues include revenues earned by certain owned providers derived from risk-based managed care agreements with our health plans. Under these agreements, the provider receives a monthly capitated fee that varies depending on the demographics and health status of the member, for each member assigned to these owned providers by our health plans. The owned provider assumes the economic risk of funding the assigned members’ healthcare services and related administrative costs. Accordingly, our Healthcare Services segment reports provider services related revenues on a gross basis. Capitation fee revenue is recognized in the period in which the assigned members are entitled to receive healthcare services.
	We present our consolidated results of operations from the perspective of the health plans. As a result, the cost of providing benefits to our members, whether provided via a third party provider or internally through a stand-alone subsidiary, is classified as benefits expense and excludes the portion of the cost for which the health plans do not bear responsibility, including member co-share amounts and government subsidies of $2.6 billion and $2.0 billion for the three months ended September 30, 2014 and 2013, respectively. For the nine months ended September 30, 2014 and 2013, these amounts were $6.8 billion and $5.2 billion respectively. In addition, depreciation and amortization expense associated with certain businesses in our Healthcare Services segment delivering benefits to our members, primarily associated with our provider services and pharmacy operations, are included with benefits expense. The amount of this expense was $27 million and $23 million for the three months ended September 30, 2014 and 2013, respectively. For the nine months ended September 30, 2014 and 2013, the amount of this expense was $79 million and $69 million, respectively.
	Other than those described previously, the accounting policies of each segment are the same and are described in Note 2 to the consolidated financial statements included in our 2013 Form 10-K. Transactions between reportable segments primarily consist of sales of services rendered by our Healthcare Services segment, primarily pharmacy, provider, and behavioral health services, to our Retail and Employer Group customers. Intersegment sales and expenses are recorded at fair value and eliminated in consolidation. Members served by our segments often use the same provider networks, enabling us in some instances to obtain more favorable contract terms with providers. Our segments also share indirect costs and assets. As a result, the profitability of each segment is interdependent. We allocate most operating expenses to our segments. Assets and certain corporate income and expenses are not allocated to the segments, including the portion of investment income not supporting segment operations, interest expense on corporate debt, and certain other corporate expenses. These items are managed at a corporate level. These corporate amounts are reported separately from our reportable segments and are included with intersegment eliminations in the tables presenting segment results below.
	Our segment results were as follows for the three and nine months ended September 30, 2014 and 2013, respectively:
		Retail		Employer		Healthcare		Other		Eliminations/			Consolidated
				Group		Services		Businesses		Corporate
		(in millions)
	Three months ended September 30, 2014
	Revenues - external customers
	Premiums:
	Medicare Advantage	$	6,508	$	1,381	$	—	$	—	$	—		$	7,889
	Medicare stand-alone PDP	804		2		—		—		—			806
	Total Medicare	7,312		1,383		—		—		—			8,695
	Fully-insured	926		1,335		—		—		—			2,261
	Specialty	67		274		—		—		—			341
	Military services	—		—		—		5		—			5
	Medicaid and other	292		—		—		13		—			305
	Total premiums	8,597		2,992		—		18		—			11,607
	Services revenue:
	Provider	—		6		302		—		—			308
	ASO and other	10		84		—		108		—			202
	Pharmacy	—		—		26		—		—			26
	Total services revenue	10		90		328		108		—			536
	Total revenues - external customers	8,607		3,082		328		126		—			12,143
	Intersegment revenues
	Services	—		22		3,851		—		(3,873		)	—
	Products	—		—		968		—		(968		)	—
	Total intersegment revenues	—		22		4,819		—		(4,841		)	—
	Investment income	19		11		—		15		50			95
	Total revenues	8,626		3,115		5,147		141		(4,791		)	12,238
	Operating expenses:
	Benefits	7,201		2,589		—		27		(151		)	9,666
	Operating costs	1,063		487		4,908		96		(4,656		)	1,898
	Depreciation and amortization	40		26		37		4		(22		)	85
	Total operating expenses	8,304		3,102		4,945		127		(4,829		)	11,649
	Income from operations	322		13		202		14		38			589
	Interest expense	—		—		—		—		38			38
	Income before income taxes	$	322	$	13	$	202	$	14	$	—		$	551
		Retail		Employer		Healthcare		Other		Eliminations/			Consolidated
				Group		Services		Businesses		Corporate
		(in millions)
	Three months ended September 30, 2013
	Revenues - external customers
	Premiums:
	Medicare Advantage	$	5,552	$	1,193	$	—	$	—	$	—		$	6,745
	Medicare stand-alone PDP	740		2		—		—		—			742
	Total Medicare	6,292		1,195		—		—		—			7,487
	Fully-insured	292		1,278		—		—		—			1,570
	Specialty	54		273		—		—		—			327
	Military services	—		—		—		6		—			6
	Medicaid and other	76		—		—		232		—			308
	Total premiums	6,714		2,746		—		238		—			9,698
	Services revenue:
	Provider	—		6		310		—		—			316
	ASO and other	3		84		—		108		—			195
	Pharmacy	—		—		17		—		—			17
	Total services revenue	3		90		327		108		—			528
	Total revenues - external customers	6,717		2,836		327		346		—			10,226
	Intersegment revenues
Services	—		14		2,999		—		(3,013		)	—
Products	—		—		716		—		(716		)	—
Total intersegment revenues	—		14		3,715		—		(3,729		)	—
Investment income	19		10		—		15		49			93
Total revenues	6,736		2,860		4,042		361		(3,680		)	10,319
Operating expenses:
Benefits	5,647		2,316		—		230		(118		)	8,075
Operating costs	718		443		3,856		103		(3,580		)	1,540
Depreciation and amortization	33		25		37		5		(17		)	83
Total operating expenses	6,398		2,784		3,893		338		(3,715		)	9,698
Income from operations	338		76		149		23		35			621
Interest expense	—		—		—		—		35			35
Income before income taxes	$	338	$	76	$	149	$	23	$	—		$	586
	Retail		Employer		Healthcare		Other		Eliminations/			Consolidated
			Group		Services		Businesses		Corporate
	(in millions)
Nine months ended September 30, 2014
Revenues - external customers
Premiums:
Medicare Advantage	$	19,443	$	4,131	$	—	$	—	$	—		$	23,574
Medicare stand-alone PDP	2,606		6		—		—		—			2,612
Total Medicare	22,049		4,137		—		—		—			26,186
Fully-insured	2,363		3,985		—		—		—			6,348
Specialty	192		824		—		—		—			1,016
Military services	—		—		—		15		—			15
Medicaid and other	667		—		—		42		—			709
Total premiums	25,271		8,946		—		57		—			34,274
Services revenue:
Provider	—		17		899		—		—			916
ASO and other	37		246		—		349		—			632
Pharmacy	—		—		72		—		—			72
Total services revenue	37		263		971		349		—			1,620
Total revenues - external customers	25,308		9,209		971		406		—			35,894
Intersegment revenues
Services	—		57		11,002		—		(11,059		)	—
Products	—		—		2,752		—		(2,752		)	—
Total intersegment revenues	—		57		13,754		—		(13,811		)	—
Investment income	56		32		—		45		145			278
Total revenues	25,364		9,298		14,725		451		(13,666		)	36,172
Operating expenses:
Benefits	21,371		7,417		—		82		(453		)	28,417
Operating costs	2,968		1,478		14,024		301		(13,253		)	5,518
Depreciation and amortization	112		75		108		12		(61		)	246
Total operating expenses	24,451		8,970		14,132		395		(13,767		)	34,181
Income from operations	913		328		593		56		101			1,991
Interest expense	—		—		—		—		108			108
Income (loss) before income taxes	$	913	$	328	$	593	$	56	$	(7	)	$	1,883
	Retail		Employer		Healthcare		Other		Eliminations/			Consolidated
			Group		Services		Businesses		Corporate
	(in millions)
Nine months ended September 30, 2013
Revenues - external customers
Premiums:
Medicare Advantage	$	16,860	$	3,543	$	—	$	—	$	—		$	20,403
Medicare stand-alone PDP	2,286		6		—		—		—			2,292
Total Medicare	19,146		3,549		—		—		—			22,695
Fully-insured	856		3,819		—		—		—			4,675
Specialty	155		823		—		—		—			978
Military services	—		—		—		22		—			22
Medicaid and other	227		—		—		670		—			897
Total premiums	20,384		8,191		—		692		—			29,267
Services revenue:
Provider	—		15		928		—		—			943
ASO and other	7		250		—		342		—			599
Pharmacy	—		—		39		—		—			39
Total services revenue	7		265		967		342		—			1,581
Total revenues - external customers	20,391		8,456		967		1,034		—			30,848
Intersegment revenues
Services	—		37		8,706		—		(8,743		)	—
Products	—		—		2,050		—		(2,050		)	—
Total intersegment revenues	—		37		10,756		—		(10,793		)	—
Investment income	55		31		—		45		147			278
Total revenues	20,446		8,524		11,723		1,079		(10,646		)	31,126
Operating expenses:
Benefits	17,272		6,728		—		668		(307		)	24,361
Operating costs	1,971		1,299		11,223		347		(10,393		)	4,447
Depreciation and amortization	97		75		109		13		(51		)	243
Total operating expenses	19,340		8,102		11,332		1,028		(10,751		)	29,051
Income from operations	1,106		422		391		51		105			2,075
Interest expense	—		—		—		—		105			105
Income before income taxes	$	1,106	$	422	$	391	$	51	$	—		$	1,970

BASIS_OF_PRESENTATION_Tables

BASIS OF PRESENTATION (Tables)	9 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Risk Adjustment, Risk Corridor, and Reinsurance Recoverable Settlements	'
	The accompanying condensed consolidated balance sheets include the following amounts associated with the 3Rs at September 30, 2014. No such amounts were recorded in our condensed consolidated balance sheet at December 31, 2013 as the programs were not effective until January 1, 2014.
		30-Sep-14
		Risk Adjustment/Risk Corridor			Reinsurance			Reinsurance
		Settlement			Contribution			Recoverables
		(in millions)
	Current assets	$	134		$	—		$	375
	Trade accounts payable and accrued expenses	(53		)	(102		)	—
	Net current asset (liability)	$	81		$	(102	)	$	375

INVESTMENT_SECURITIES_Tables

INVESTMENT SECURITIES (Tables)	9 Months Ended
	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
Schedule of Investment Securities Classified as Current and Long-Term	'
	Investment securities classified as current and long-term were as follows at September 30, 2014 and December 31, 2013, respectively:
		Amortized			Gross			Gross			Fair
		Cost			Unrealized			Unrealized			Value
					Gains			Losses
		(in millions)
	30-Sep-14
	U.S. Treasury and other U.S. government
	corporations and agencies:
	U.S. Treasury and agency obligations	$	846		$	8		$	(2	)	$	852
	Mortgage-backed securities	1,544			42			(17		)	1,569
	Tax-exempt municipal securities	3,006			148			(3		)	3,151
	Mortgage-backed securities:
	Residential	18			—			—			18
	Commercial	698			15			(17		)	696
	Asset-backed securities	40			1			—			41
	Corporate debt securities	3,431			289			(12		)	3,708
	Total debt securities	$	9,583		$	503		$	(51	)	$	10,035
	31-Dec-13
	U.S. Treasury and other U.S. government
	corporations and agencies:
	U.S. Treasury and agency obligations	$	584		$	6		$	(6	)	$	584
	Mortgage-backed securities	1,834			34			(48		)	1,820
	Tax-exempt municipal securities	2,911			93			(33		)	2,971
	Mortgage-backed securities:
	Residential	22			—			—			22
	Commercial	662			20			(9		)	673
	Asset-backed securities	63			1			(1		)	63
	Corporate debt securities	3,474			223			(30		)	3,667
	Total debt securities	$	9,550		$	377		$	(127	)	$	9,800
Schedule of Gross Unrealized Losses and Fair Value of Securities	'
	Gross unrealized losses and fair values aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position were as follows at September 30, 2014 and December 31, 2013, respectively:
		Less than 12 months						12 months or more						Total
		Fair			Gross			Fair			Gross			Fair		Gross
		Value			Unrealized			Value			Unrealized			Value		Unrealized
					Losses						Losses					Losses
		(in millions)
	30-Sep-14
	U.S. Treasury and other U.S.
	government corporations
	and agencies:
	U.S. Treasury and agency	$	59		$	—		$	86		$	(2	)	$	145	$	(2	)
	obligations
	Mortgage-backed	147			(1		)	475			(16		)	622		(17		)
	securities
	Tax-exempt municipal	136			—			136			(3		)	272		(3		)
	securities
	Mortgage-backed securities:
	Residential	1			—			4			—			5		—
	Commercial	145			(3		)	206			(14		)	351		(17		)
	Asset-backed securities	—			—			16			—			16		—
	Corporate debt securities	209			(3		)	141			(9		)	350		(12		)
	Total debt securities	$	697		$	(7	)	$	1,064		$	(44	)	$	1,761	$	(51	)
	31-Dec-13
	U.S. Treasury and other U.S.
	government corporations
	and agencies:
	U.S. Treasury and agency	$	231		$	(6	)	$	5		$	—		$	236	$	(6	)
	obligations
	Mortgage-backed	1,076			(47		)	21			(1		)	1,097		(48		)
	securities
	Tax-exempt municipal	693			(28		)	57			(5		)	750		(33		)
	securities
	Mortgage-backed securities:
	Residential	6			—			1			—			7		—
	Commercial	270			(8		)	40			(1		)	310		(9		)
	Asset-backed securities	35			(1		)	—			—			35		(1		)
	Corporate debt securities	594			(28		)	17			(2		)	611		(30		)
	Total debt securities	$	2,905		$	(118	)	$	141		$	(9	)	$	3,046	$	(127	)
Schedule of Realized Gains (Losses) Related to Investment Securities Included Within Investment Income	'
	The detail of realized gains (losses) related to investment securities and included within investment income was as follows for the three and nine months ended September 30, 2014 and 2013:
		Three months ended						Nine months ended
		September 30,						September 30,
		2014			2013			2014			2013
		(in millions)
	Gross realized gains	$	7		$	7		$	14		$	24
	Gross realized losses	(1		)	(3		)	(5		)	(10		)
	Net realized capital gains	$	6		$	4		$	9		$	14
Schedule of Contractual Maturity of Debt Securities Available for Sale	'
	The contractual maturities of debt securities available for sale at September 30, 2014, regardless of their balance sheet classification, are shown below. Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.
		Amortized			Fair
		Cost			Value
		(in millions)
	Due within one year	$	1,030		$	1,036
	Due after one year through five years	2,119			2,234
	Due after five years through ten years	2,184			2,307
	Due after ten years	1,950			2,134
	Mortgage and asset-backed securities	2,300			2,324
	Total debt securities	$	9,583		$	10,035

FAIR_VALUE_Tables

FAIR VALUE (Tables)	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Financial Assets Measured at Fair Value on Recurring Basis	'
	The following table summarizes our fair value measurements at September 30, 2014 and December 31, 2013, respectively, for financial assets measured at fair value on a recurring basis:
		Fair Value Measurements Using
		Fair		Quoted Prices		Other		Unobservable
		Value		in Active		Observable		Inputs
				Markets		Inputs		(Level 3)
				(Level 1)		(Level 2)
		(in millions)
	30-Sep-14
	Cash equivalents	$	2,606	$	2,606	$	—	$	—
	Debt securities:
	U.S. Treasury and other U.S. government
	corporations and agencies:
	U.S. Treasury and agency obligations	852		—		852		—
	Mortgage-backed securities	1,569		—		1,569		—
	Tax-exempt municipal securities	3,151		—		3,138		13
	Mortgage-backed securities:
	Residential	18		—		18		—
	Commercial	696		—		696		—
	Asset-backed securities	41		—		40		1
	Corporate debt securities	3,708		—		3,684		24
	Total debt securities	10,035		—		9,997		38
	Total invested assets	$	12,641	$	2,606	$	9,997	$	38
	31-Dec-13
	Cash equivalents	$	876	$	876	$	—	$	—
	Debt securities:
	U.S. Treasury and other U.S. government
	corporations and agencies:
	U.S. Treasury and agency obligations	584		—		584		—
	Mortgage-backed securities	1,820		—		1,820		—
	Tax-exempt municipal securities	2,971		—		2,958		13
	Mortgage-backed securities:
	Residential	22		—		22		—
	Commercial	673		—		673		—
	Asset-backed securities	63		—		62		1
	Corporate debt securities	3,667		—		3,644		23
	Total debt securities	9,800		—		9,763		37
	Total invested assets	$	10,676	$	876	$	9,763	$	37
Changes in Fair Value of Assets Measured Using Significant Unobservable Inputs	'
	During the three and nine months ended September 30, 2014 and 2013, the changes in the fair value of the assets measured using significant unobservable inputs (Level 3) were comprised of the following:
		For the three months ended September 30,
		2014						2013
		Private		Auction		Total		Private			Auction		Total
		Placements		Rate				Placements			Rate
				Securities							Securities
		(in millions)
	Beginning balance at April 1	$	24	$	13	$	37	$	23		$	13	$	36
	Total gains or losses:
	Realized in earnings	—		—		—		—			—		—
	Unrealized in other	1		—		1		1			—		1
	comprehensive income
	Purchases	—		—		—		—			—		—
	Sales	—		—		—		—			—		—
	Settlements	—		—		—		—			—		—
	Balance at September 30	$	25	$	13	$	38	$	24		$	13	$	37
		For the nine months ended September 30,
		2014						2013
		Private		Auction		Total		Private			Auction		Total
		Placements		Rate				Placements			Rate
				Securities							Securities
		(in millions)
	Beginning balance at January 1	$	24	$	13	$	37	$	25		$	13	$	38
	Total gains or losses:
	Realized in earnings	—		—		—		—			—		—
	Unrealized in other	1		—		1		—			—		—
	comprehensive income
	Purchases	—		—		—		—			—		—
	Sales	—		—		—		—			—		—
	Settlements	—		—		—		(1		)	—		(1		)
	Balance at September 30	$	25	$	13	$	38	$	24		$	13	$	37

MEDICARE_PART_D_Tables

MEDICARE PART D (Tables)	9 Months Ended
	Sep. 30, 2014
Insurance [Abstract]	'
Balance Sheet Amounts Associated With Medicare Part D	'
	The accompanying condensed consolidated balance sheets include the following amounts associated with Medicare Part D at September 30, 2014 and December 31, 2013. Amounts included below relating to the 2013 contract year for the net risk corridor payable of $35 million and the CMS subsidies receivable of $691 million at September 30, 2014 were settled in October 2014.
		30-Sep-14						31-Dec-13
		Risk			CMS			Risk			CMS
		Corridor			Subsidies/			Corridor			Subsidies/
		Settlement			Discounts			Settlement			Discounts
		(in millions)
	Other current assets	$	205		$	1,517		$	45		$	743
	Trade accounts payable and accrued expenses	(80		)	(43		)	(71		)	(30		)
	Net current (liability) asset	125			1,474			(26		)	713

GOODWILL_AND_OTHER_INTANGIBLE_1

GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)	9 Months Ended
	Sep. 30, 2014
Goodwill and Intangible Assets Disclosure [Abstract]	'
Changes in Carrying Amount of Goodwill By Reportable Segments	'
	Changes in the carrying amount of goodwill for our reportable segments for the nine months ended September 30, 2014 were as follows:
		Retail				Employer				Healthcare				Other				Total
						Group				Services				Businesses
		(in millions)
	Balance at January 1, 2014	$	1,007			$	363			$	2,271			$	92			$	3,733
	Acquisitions	—				—				3				—				3
	Dispositions	—				—				(40		)		—				(40		)
	Subsequent payments/adjustments	—				—				(1		)		—				(1		)
	Balance at September 30, 2014	$	1,007			$	363			$	2,233			$	92			$	3,695
Details of Intangible Assets Included in Other Long-Term Assets	'
	The following table presents details of our other intangible assets included in other long-term assets in the accompanying condensed consolidated balance sheets at September 30, 2014 and December 31, 2013:
				30-Sep-14												31-Dec-13
		Weighted		Cost				Accumulated				Net				Cost				Accumulated		Net
		Average						Amortization												Amortization
		Life
		(in millions)
	Other intangible assets:
	Customer contracts/	9.8 yrs		$	764			$	349			$	415			$	792			$	310	$	482
	relationships
	Trade names and	13.2 yrs		198				54				144				200				40		160
	technology
	Provider contracts	15.1 yrs		51				19				32				51				23		28
	Noncompetes and	6.6 yrs		50				34				16				52				29		23
	other
	Total other intangible	10.5 yrs		$	1,063			$	456			$	607			$	1,095			$	402	$	693
	assets
Schedule of Estimated Amortization Expense	'
	The following table presents our estimate of amortization expense for 2014 and each of the five next succeeding years:
		(in millions)
	For the years ending December 31,:
	2014	$	112
	2015	101
	2016	94
	2017	86
	2018	79
	2019	67

EARNINGS_PER_COMMON_SHARE_COMP1

EARNINGS PER COMMON SHARE COMPUTATION (Tables)	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Schedule of Details Supporting Computation of Earnings Per Share	'
	Detail supporting the computation of basic and diluted earnings per common share was as follows for the three and nine months ended September 30, 2014 and 2013:
		Three months ended September 30,				Nine months ended September 30,
		2014		2013		2014		2013
		(dollars in millions, except per common share results; number of shares in thousands)
	Net income available for common stockholders	$	290	$	368	$	1,002	$	1,261
	Weighted average outstanding shares of common stock	154,502		157,187		155,006		158,026
	used to compute basic earnings per common share
	Dilutive effect of:
	Employee stock options	203		289		233		341
	Restricted stock	1,525		1,431		1,402		1,244
	Shares used to compute diluted earnings per common share	156,230		158,907		156,641		159,611
	Basic earnings per common share	$	1.87	$	2.34	$	6.46	$	7.98
	Diluted earnings per common share	$	1.85	$	2.31	$	6.39	$	7.9
	Number of antidilutive stock options and restricted stock	43		202		420		910
	excluded from computation

STOCKHOLDERS_EQUITY_Tables

STOCKHOLDERS' EQUITY (Tables)	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
Schedule of Details of Dividend Payments	'
	The following table provides details of dividend payments in 2013 and 2014 under our Board approved quarterly cash dividend policy:
	Record	Payment	Amount		Total
	Date	Date	per Share		Amount
					(in millions)
	2013 payments
	12/31/12	1/25/13	$	0.26	$	42
	3/28/13	4/26/13	$	0.26	$	41
	6/28/13	7/26/13	$	0.27	$	42
	9/30/13	10/25/13	$	0.27	$	42
	2014 payments
	12/31/13	1/31/14	$	0.27	$	42
	3/31/14	4/25/14	$	0.27	$	42
	6/30/14	7/25/14	$	0.28	$	43
	9/30/14	10/31/14	$	0.28	$	43

DEBT_Tables

DEBT (Tables)	9 Months Ended
	Sep. 30, 2014
Debt Disclosure [Abstract]	'
Schedule of carrying value of long-term debt outstanding	'
	The carrying value of long-term debt outstanding, including the current portion, was as follows at September 30, 2014 and December 31, 2013:
		September 30, 2014		December 31, 2013
		(in millions)
	Senior notes:
	$500 million, 6.45% due June 1, 2016	$	512	$	517
	$500 million, 7.20% due June 15, 2018	505		505
	$300 million, 6.30% due August 1, 2018	312		314
	$400 million, 2.625% due October 1, 2019	400		—
	$600 million, 3.15% due December 1, 2022	598		598
	$600 million, 3.85% due October 1, 2024	599		—
	$250 million, 8.15% due June 15, 2038	266		266
	$400 million, 4.625% due December 1, 2042	400		400
	$750 million, 4.95% due October 1, 2044	746		—
	Total debt	$	4,338	$	2,600
	Less current portion of long-term debt	512		—
	Total long-term debt	$	3,826	$	2,600

SEGMENT_INFORMATION_Tables

SEGMENT INFORMATION (Tables)	9 Months Ended
	Sep. 30, 2014
Segment Reporting [Abstract]	'
Schedule of Segment Reporting Information, By Segment	'
	Our segment results were as follows for the three and nine months ended September 30, 2014 and 2013, respectively:
		Retail		Employer		Healthcare		Other		Eliminations/			Consolidated
				Group		Services		Businesses		Corporate
		(in millions)
	Three months ended September 30, 2014
	Revenues - external customers
	Premiums:
	Medicare Advantage	$	6,508	$	1,381	$	—	$	—	$	—		$	7,889
	Medicare stand-alone PDP	804		2		—		—		—			806
	Total Medicare	7,312		1,383		—		—		—			8,695
	Fully-insured	926		1,335		—		—		—			2,261
	Specialty	67		274		—		—		—			341
	Military services	—		—		—		5		—			5
	Medicaid and other	292		—		—		13		—			305
	Total premiums	8,597		2,992		—		18		—			11,607
	Services revenue:
	Provider	—		6		302		—		—			308
	ASO and other	10		84		—		108		—			202
	Pharmacy	—		—		26		—		—			26
	Total services revenue	10		90		328		108		—			536
	Total revenues - external customers	8,607		3,082		328		126		—			12,143
	Intersegment revenues
	Services	—		22		3,851		—		(3,873		)	—
	Products	—		—		968		—		(968		)	—
	Total intersegment revenues	—		22		4,819		—		(4,841		)	—
	Investment income	19		11		—		15		50			95
	Total revenues	8,626		3,115		5,147		141		(4,791		)	12,238
	Operating expenses:
	Benefits	7,201		2,589		—		27		(151		)	9,666
	Operating costs	1,063		487		4,908		96		(4,656		)	1,898
	Depreciation and amortization	40		26		37		4		(22		)	85
	Total operating expenses	8,304		3,102		4,945		127		(4,829		)	11,649
	Income from operations	322		13		202		14		38			589
	Interest expense	—		—		—		—		38			38
	Income before income taxes	$	322	$	13	$	202	$	14	$	—		$	551
		Retail		Employer		Healthcare		Other		Eliminations/			Consolidated
				Group		Services		Businesses		Corporate
		(in millions)
	Three months ended September 30, 2013
	Revenues - external customers
	Premiums:
	Medicare Advantage	$	5,552	$	1,193	$	—	$	—	$	—		$	6,745
	Medicare stand-alone PDP	740		2		—		—		—			742
	Total Medicare	6,292		1,195		—		—		—			7,487
	Fully-insured	292		1,278		—		—		—			1,570
	Specialty	54		273		—		—		—			327
	Military services	—		—		—		6		—			6
	Medicaid and other	76		—		—		232		—			308
	Total premiums	6,714		2,746		—		238		—			9,698
	Services revenue:
	Provider	—		6		310		—		—			316
	ASO and other	3		84		—		108		—			195
	Pharmacy	—		—		17		—		—			17
	Total services revenue	3		90		327		108		—			528
	Total revenues - external customers	6,717		2,836		327		346		—			10,226
	Intersegment revenues
	Services	—		14		2,999		—		(3,013		)	—
	Products	—		—		716		—		(716		)	—
	Total intersegment revenues	—		14		3,715		—		(3,729		)	—
	Investment income	19		10		—		15		49			93
	Total revenues	6,736		2,860		4,042		361		(3,680		)	10,319
	Operating expenses:
	Benefits	5,647		2,316		—		230		(118		)	8,075
Operating costs	718		443		3,856		103		(3,580		)	1,540
Depreciation and amortization	33		25		37		5		(17		)	83
Total operating expenses	6,398		2,784		3,893		338		(3,715		)	9,698
Income from operations	338		76		149		23		35			621
Interest expense	—		—		—		—		35			35
Income before income taxes	$	338	$	76	$	149	$	23	$	—		$	586
	Retail		Employer		Healthcare		Other		Eliminations/			Consolidated
			Group		Services		Businesses		Corporate
	(in millions)
Nine months ended September 30, 2014
Revenues - external customers
Premiums:
Medicare Advantage	$	19,443	$	4,131	$	—	$	—	$	—		$	23,574
Medicare stand-alone PDP	2,606		6		—		—		—			2,612
Total Medicare	22,049		4,137		—		—		—			26,186
Fully-insured	2,363		3,985		—		—		—			6,348
Specialty	192		824		—		—		—			1,016
Military services	—		—		—		15		—			15
Medicaid and other	667		—		—		42		—			709
Total premiums	25,271		8,946		—		57		—			34,274
Services revenue:
Provider	—		17		899		—		—			916
ASO and other	37		246		—		349		—			632
Pharmacy	—		—		72		—		—			72
Total services revenue	37		263		971		349		—			1,620
Total revenues - external customers	25,308		9,209		971		406		—			35,894
Intersegment revenues
Services	—		57		11,002		—		(11,059		)	—
Products	—		—		2,752		—		(2,752		)	—
Total intersegment revenues	—		57		13,754		—		(13,811		)	—
Investment income	56		32		—		45		145			278
Total revenues	25,364		9,298		14,725		451		(13,666		)	36,172
Operating expenses:
Benefits	21,371		7,417		—		82		(453		)	28,417
Operating costs	2,968		1,478		14,024		301		(13,253		)	5,518
Depreciation and amortization	112		75		108		12		(61		)	246
Total operating expenses	24,451		8,970		14,132		395		(13,767		)	34,181
Income from operations	913		328		593		56		101			1,991
Interest expense	—		—		—		—		108			108
Income (loss) before income taxes	$	913	$	328	$	593	$	56	$	(7	)	$	1,883
	Retail		Employer		Healthcare		Other		Eliminations/			Consolidated
			Group		Services		Businesses		Corporate
	(in millions)
Nine months ended September 30, 2013
Revenues - external customers
Premiums:
Medicare Advantage	$	16,860	$	3,543	$	—	$	—	$	—		$	20,403
Medicare stand-alone PDP	2,286		6		—		—		—			2,292
Total Medicare	19,146		3,549		—		—		—			22,695
Fully-insured	856		3,819		—		—		—			4,675
Specialty	155		823		—		—		—			978
Military services	—		—		—		22		—			22
Medicaid and other	227		—		—		670		—			897
Total premiums	20,384		8,191		—		692		—			29,267
Services revenue:
Provider	—		15		928		—		—			943
ASO and other	7		250		—		342		—			599
Pharmacy	—		—		39		—		—			39
Total services revenue	7		265		967		342		—			1,581
Total revenues - external customers	20,391		8,456		967		1,034		—			30,848
Intersegment revenues
Services	—		37		8,706		—		(8,743		)	—
Products	—		—		2,050		—		(2,050		)	—
Total intersegment revenues	—		37		10,756		—		(10,793		)	—
Investment income	55		31		—		45		147			278
Total revenues	20,446		8,524		11,723		1,079		(10,646		)	31,126
Operating expenses:
Benefits	17,272		6,728		—		668		(307		)	24,361
Operating costs	1,971		1,299		11,223		347		(10,393		)	4,447
Depreciation and amortization	97		75		109		13		(51		)	243
Total operating expenses	19,340		8,102		11,332		1,028		(10,751		)	29,051
Income from operations	1,106		422		391		51		105			2,075
Interest expense	—		—		—		—		105			105
Income before income taxes	$	1,106	$	422	$	391	$	51	$	—		$	1,970

Basis_of_Presentation_Addition

Basis of Presentation - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended		1 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014
					Health Care Reform	Health Care Reform	Health Care Reform	Commercial Medical
						Program
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]	'	'	'	'	'	'	'	'
Number of premium stabilization programs	'	'	'	'	'	3	'	'
Annual health insurance industry fee paid in September 2014	'	'	'	'	$562,000,000	'	'	'
Operating cost expense associated with amortization of deferred cost	'	'	'	'	'	421,000,000	'	'
Deferred cost asset	'	'	'	'	141,000,000	141,000,000	0	'
Percentage of premiums and services revenue applicable to risk spreading programs	'	'	'	'	'	'	'	17.70%
Operating costs associated with transitional reinsurance contributions	'	'	'	'	'	77,000,000	'	'
Ceded premiums	'	'	'	'	'	25,000,000	0	'
Ceded benefits	'	'	'	'	'	375,000,000	0	'
Payments due to HHS under risk adjustment, remittance period	'	'	'	'	'	'30 days	'	'
Proceed for health care cost sharing subsidies for low-income individual members	$2,600,000,000	$2,000,000,000	$6,800,000,000	$5,200,000,000	'	$29,000,000	'	'

Basis_of_Presentation_Risk_Adj

Basis of Presentation - Risk Adjustment, Risk Corridor and Reinsurance Recoverable Settlements (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Effects of Risk Spreading Premium Stabilization Programs [Line Items]	'	'
Current assets	$15,636	$12,300
Trade accounts payable and accrued expenses	-2,068	-1,821
Risk Adjustment/Risk Corridor Settlement | Health Care Reform	'	'
Effects of Risk Spreading Premium Stabilization Programs [Line Items]	'	'
Current assets	134	0
Trade accounts payable and accrued expenses	-53	0
Net current asset (liability)	81	0
Reinsurance Contribution | Health Care Reform	'	'
Effects of Risk Spreading Premium Stabilization Programs [Line Items]	'	'
Current assets	0	0
Trade accounts payable and accrued expenses	-102	0
Net current asset (liability)	-102	0
Reinsurance Recoverables | Health Care Reform	'	'
Effects of Risk Spreading Premium Stabilization Programs [Line Items]	'	'
Current assets	375	0
Trade accounts payable and accrued expenses	0	0
Net current asset (liability)	$375	$0

RECENTLY_ISSUED_ACCOUNTING_PRO1

RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS Recently Issued Accounting Pronouncements (Details) (Healthcare Services, Segment Revenue Concentration Risk, Sales Revenue)	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014
Healthcare Services | Segment Revenue Concentration Risk | Sales Revenue	'	'
Concentration Risk [Line Items]	'	'
Service revenue as a percent of consolidated revenues (less than 5%)	5.00%	5.00%

Acquisitions_Additional_Inform

Acquisitions - Additional Information (Detail) (USD $)	9 Months Ended		0 Months Ended		0 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013	Sep. 06, 2013	Sep. 06, 2013	Sep. 06, 2013
			American Eldercare Inc.	American Eldercare Inc.	Customer Contracts and Technology
					American Eldercare Inc.
Business Acquisition [Line Items]	'	'	'	'	'
Date of acquisition	'	'	6-Sep-13	'	'
Goodwill acquired	$3,695	$3,733	'	$76	'
Amount allocated to other intangible assets	'	'	'	$75	'
Other intangible assets useful life, years	'10 years 5 months 24 days	'	'	'	'9 years 3 months 18 days

Investment_Securities_Addition

Investment Securities - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]	'	'	'	'	'
Percentage of debt securities considered to be of investment-grade	96.00%	'	96.00%	'	'
Percentage of tax-exempt municipal securities classified as pre-refunded	5.00%	'	5.00%	'	'
General obligation bonds as percentage of tax-exempt municipal securities that were not pre-refunded	'	'	39.00%	'	'
Special revenue bonds as percentage of tax exempt municipal securities that were not pre-refunded	'	'	61.00%	'	'
Maximum percentage of any general obligation bonds in one state	'	'	11.00%	'	'
Percentage of tax-exempt securities insured by bond insurers	16.00%	'	16.00%	'	'
Residential and commercial mortgage-backed securities, percentage of collateral consisting of prime loans	99.00%	'	99.00%	'	'
Percentage of corporate securities associated with financial services industry	20.00%	'	20.00%	'	23.00%
Other-than-temporary impairments	$0	$0	$0	$0	'

Schedule_of_Investment_Securit

Schedule of Investment Securities Classified as Current and Long-Term (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Investment [Line Items]	'	'
Amortized Cost	$9,583	$9,550
Gross Unrealized Gains	503	377
Gross Unrealized Losses	-51	-127
Total debt securities, Fair Value	10,035	9,800
Debt Securities | Tax-exempt municipal securities	'	'
Investment [Line Items]	'	'
Amortized Cost	3,006	2,911
Gross Unrealized Gains	148	93
Gross Unrealized Losses	-3	-33
Total debt securities, Fair Value	3,151	2,971
Debt Securities | Residential Mortgage-Backed Securities	'	'
Investment [Line Items]	'	'
Amortized Cost	18	22
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Total debt securities, Fair Value	18	22
Debt Securities | Commercial Mortgage-Backed Securities	'	'
Investment [Line Items]	'	'
Amortized Cost	698	662
Gross Unrealized Gains	15	20
Gross Unrealized Losses	-17	-9
Total debt securities, Fair Value	696	673
Debt Securities | Asset-backed Securities	'	'
Investment [Line Items]	'	'
Amortized Cost	40	63
Gross Unrealized Gains	1	1
Gross Unrealized Losses	0	-1
Total debt securities, Fair Value	41	63
Debt Securities | Corporate Debt Securities	'	'
Investment [Line Items]	'	'
Amortized Cost	3,431	3,474
Gross Unrealized Gains	289	223
Gross Unrealized Losses	-12	-30
Total debt securities, Fair Value	3,708	3,667
Debt Securities | U.S. Treasury And Other U.S. Government Corporations And Agencies | U.S. Treasury And Agency Obligations	'	'
Investment [Line Items]	'	'
Amortized Cost	846	584
Gross Unrealized Gains	8	6
Gross Unrealized Losses	-2	-6
Total debt securities, Fair Value	852	584
Debt Securities | U.S. Treasury And Other U.S. Government Corporations And Agencies | Mortgage-Backed Securities	'	'
Investment [Line Items]	'	'
Amortized Cost	1,544	1,834
Gross Unrealized Gains	42	34
Gross Unrealized Losses	-17	-48
Total debt securities, Fair Value	$1,569	$1,820

Schedule_of_Gross_Unrealized_L

Schedule of Gross Unrealized Losses and Fair Values of Securities (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Investment [Line Items]	'	'
Less than 12 months, Fair Value	$697	$2,905
Less than 12 months, Gross Unrealized Losses	-7	-118
12 months or more, Fair Value	1,064	141
12 months or more, Gross Unrealized Losses	-44	-9
Total, Fair Value	1,761	3,046
Total, Gross Unrealized Losses	-51	-127
Debt Securities | Tax-exempt municipal securities	'	'
Investment [Line Items]	'	'
Less than 12 months, Fair Value	136	693
Less than 12 months, Gross Unrealized Losses	0	-28
12 months or more, Fair Value	136	57
12 months or more, Gross Unrealized Losses	-3	-5
Total, Fair Value	272	750
Total, Gross Unrealized Losses	-3	-33
Debt Securities | Residential Mortgage-Backed Securities	'	'
Investment [Line Items]	'	'
Less than 12 months, Fair Value	1	6
Less than 12 months, Gross Unrealized Losses	0	0
12 months or more, Fair Value	4	1
12 months or more, Gross Unrealized Losses	0	0
Total, Fair Value	5	7
Total, Gross Unrealized Losses	0	0
Debt Securities | Commercial Mortgage-Backed Securities	'	'
Investment [Line Items]	'	'
Less than 12 months, Fair Value	145	270
Less than 12 months, Gross Unrealized Losses	-3	-8
12 months or more, Fair Value	206	40
12 months or more, Gross Unrealized Losses	-14	-1
Total, Fair Value	351	310
Total, Gross Unrealized Losses	-17	-9
Debt Securities | Asset-backed Securities	'	'
Investment [Line Items]	'	'
Less than 12 months, Fair Value	0	35
Less than 12 months, Gross Unrealized Losses	0	-1
12 months or more, Fair Value	16	0
12 months or more, Gross Unrealized Losses	0	0
Total, Fair Value	16	35
Total, Gross Unrealized Losses	0	-1
Debt Securities | Corporate Debt Securities	'	'
Investment [Line Items]	'	'
Less than 12 months, Fair Value	209	594
Less than 12 months, Gross Unrealized Losses	-3	-28
12 months or more, Fair Value	141	17
12 months or more, Gross Unrealized Losses	-9	-2
Total, Fair Value	350	611
Total, Gross Unrealized Losses	-12	-30
Debt Securities | U.S. Treasury And Other U.S. Government Corporations And Agencies | U.S. Treasury And Agency Obligations	'	'
Investment [Line Items]	'	'
Less than 12 months, Fair Value	59	231
Less than 12 months, Gross Unrealized Losses	0	-6
12 months or more, Fair Value	86	5
12 months or more, Gross Unrealized Losses	-2	0
Total, Fair Value	145	236
Total, Gross Unrealized Losses	-2	-6
Debt Securities | U.S. Treasury And Other U.S. Government Corporations And Agencies | Mortgage-Backed Securities	'	'
Investment [Line Items]	'	'
Less than 12 months, Fair Value	147	1,076
Less than 12 months, Gross Unrealized Losses	-1	-47
12 months or more, Fair Value	475	21
12 months or more, Gross Unrealized Losses	-16	-1
Total, Fair Value	622	1,097
Total, Gross Unrealized Losses	($17)	($48)

Schedule_of_Realized_Gains_Los

Schedule of Realized Gains (Losses) Related to Investment Securities Included Within Investment Income (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Investments, Debt and Equity Securities [Abstract]	'	'	'	'
Gross realized gains	$7	$7	$14	$24
Gross realized losses	-1	-3	-5	-10
Net realized capital gains	$6	$4	$9	$14

Schedule_of_Contractual_Maturi

Schedule of Contractual Maturities of Debt Securities Available for Sale (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Available-for-sale Securities, Debt Maturities [Abstract]	'	'
Due within one year, Amortized Cost	$1,030	'
Due after one year through five years, Amortized Cost	2,119	'
Due after five years through ten years, Amortized Cost	2,184	'
Due after ten years, Amortized Cost	1,950	'
Mortgage and asset-backed securities, Amortized Cost	2,300	'
Amortized Cost	9,583	9,550
Due within one year, Fair Value	1,036	'
Due after one year through five years, Fair Value	2,234	'
Due after five years through ten years, Fair Value	2,307	'
Due after ten years, Fair Value	2,134	'
Mortgage and asset-backed securities, Fair Value	2,324	'
Total debt securities, Fair Value	$10,035	$9,800

Fair_Value_Additional_Informat

Fair Value - Additional Information (Detail) (USD $)	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
Fair Value Disclosures [Abstract]	'	'	'	'	'	'
Transfers between Level 1 and Level 2	$0	'	'	$0	'	'
Level 3 assets fair value	38,000,000	37,000,000	37,000,000	37,000,000	36,000,000	38,000,000
Upper limit percentage of Level 3 assets to total invested assets	0.30%	'	'	'	'	'
Long-term debt, carrying value	3,826,000,000	'	2,600,000,000	'	'	'
Carrying value of long-term debt	4,338,000,000	'	2,600,000,000	'	'	'
Long-term debt, fair value	$4,565,000,000	'	$2,751,000,000	'	'	'

Financial_Assets_Measured_at_F

Financial Assets Measured at Fair Value on Recurring Basis (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	$10,035	$9,800
Measured On Recurring Basis	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash equivalents	2,606	876
Total debt securities, Fair Value	10,035	9,800
Total invested assets	12,641	10,676
Measured On Recurring Basis | Tax-exempt municipal securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	3,151	2,971
Measured On Recurring Basis | Residential Mortgage-Backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	18	22
Measured On Recurring Basis | Commercial Mortgage-Backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	696	673
Measured On Recurring Basis | Asset-backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	41	63
Measured On Recurring Basis | Corporate Debt Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	3,708	3,667
Measured On Recurring Basis | U.S. Treasury And Other U.S. Government Corporations And Agencies | U.S. Treasury And Agency Obligations	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	852	584
Measured On Recurring Basis | U.S. Treasury And Other U.S. Government Corporations And Agencies | Mortgage-Backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	1,569	1,820
Quoted Prices in Active Markets for Identical Assets (Level 1) | Measured On Recurring Basis	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash equivalents	2,606	876
Total debt securities, Fair Value	0	0
Total invested assets	2,606	876
Quoted Prices in Active Markets for Identical Assets (Level 1) | Measured On Recurring Basis | Tax-exempt municipal securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Measured On Recurring Basis | Residential Mortgage-Backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Measured On Recurring Basis | Commercial Mortgage-Backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Measured On Recurring Basis | Asset-backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Measured On Recurring Basis | Corporate Debt Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Measured On Recurring Basis | U.S. Treasury And Other U.S. Government Corporations And Agencies | U.S. Treasury And Agency Obligations	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Measured On Recurring Basis | U.S. Treasury And Other U.S. Government Corporations And Agencies | Mortgage-Backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	0	0
Significant Other Observable Inputs (Level 2) | Measured On Recurring Basis	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash equivalents	0	0
Total debt securities, Fair Value	9,997	9,763
Total invested assets	9,997	9,763
Significant Other Observable Inputs (Level 2) | Measured On Recurring Basis | Tax-exempt municipal securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	3,138	2,958
Significant Other Observable Inputs (Level 2) | Measured On Recurring Basis | Residential Mortgage-Backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	18	22
Significant Other Observable Inputs (Level 2) | Measured On Recurring Basis | Commercial Mortgage-Backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	696	673
Significant Other Observable Inputs (Level 2) | Measured On Recurring Basis | Asset-backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	40	62
Significant Other Observable Inputs (Level 2) | Measured On Recurring Basis | Corporate Debt Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	3,684	3,644
Significant Other Observable Inputs (Level 2) | Measured On Recurring Basis | U.S. Treasury And Other U.S. Government Corporations And Agencies | U.S. Treasury And Agency Obligations	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	852	584
Significant Other Observable Inputs (Level 2) | Measured On Recurring Basis | U.S. Treasury And Other U.S. Government Corporations And Agencies | Mortgage-Backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	1,569	1,820
Significant Unobservable Inputs (Level 3) | Measured On Recurring Basis	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash equivalents	0	0
Total debt securities, Fair Value	38	37
Total invested assets	38	37
Significant Unobservable Inputs (Level 3) | Measured On Recurring Basis | Tax-exempt municipal securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	13	13
Significant Unobservable Inputs (Level 3) | Measured On Recurring Basis | Residential Mortgage-Backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	0	0
Significant Unobservable Inputs (Level 3) | Measured On Recurring Basis | Commercial Mortgage-Backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	0	0
Significant Unobservable Inputs (Level 3) | Measured On Recurring Basis | Asset-backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	1	1
Significant Unobservable Inputs (Level 3) | Measured On Recurring Basis | Corporate Debt Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	24	23
Significant Unobservable Inputs (Level 3) | Measured On Recurring Basis | U.S. Treasury And Other U.S. Government Corporations And Agencies | U.S. Treasury And Agency Obligations	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	0	0
Significant Unobservable Inputs (Level 3) | Measured On Recurring Basis | U.S. Treasury And Other U.S. Government Corporations And Agencies | Mortgage-Backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	$0	$0

Changes_in_Fair_Value_of_Asset

Changes in Fair Value of Assets Measured Using Significant Unobservable Inputs (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Beginning Balance	$37	$36	$37	$38
Realized in earnings	0	0	0	0
Unrealized in other comprehensive income	1	1	1	0
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements	0	0	0	-1
Ending Balance	38	37	38	37
Private Placement	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Beginning Balance	24	23	24	25
Realized in earnings	0	0	0	0
Unrealized in other comprehensive income	1	1	1	0
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements	0	0	0	-1
Ending Balance	25	24	25	24
Auction Rate Securities	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Beginning Balance	13	13	13	13
Realized in earnings	0	0	0	0
Unrealized in other comprehensive income	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements	0	0	0	0
Ending Balance	$13	$13	$13	$13

Balance_Sheet_Amounts_Associat

Balance Sheet Amounts Associated With Medicare Part D (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Dec. 31, 2013	Oct. 31, 2014	Oct. 31, 2014
In Millions, unless otherwise specified			Risk Corridor Settlement	Risk Corridor Settlement	CMS Subsidies/ Discounts	CMS Subsidies/ Discounts	Subsequent Event	Subsequent Event
							Risk Corridor Settlement	CMS Subsidies/ Discounts
Segment Reporting Information [Line Items]	'	'	'	'	'	'	'	'
Payable settled	'	'	'	'	'	'	$35	'
Receivable settled	'	'	'	'	'	'	'	691
Other current assets	3,839	2,122	205	45	1,517	743	'	'
Trade accounts payable and accrued expenses	-2,068	-1,821	-80	-71	-43	-30	'	'
Net current asset (liability)	'	'	$125	($26)	$1,474	$713	'	'

Recovered_Sheet1

Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'	'	'	'
Amortization expense for other intangible assets	$28	$28	$85	$84

Changes_in_Carrying_Amount_of_

Changes in Carrying Amount of Goodwill by Reportable Segments (Detail) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014
Goodwill [Line Items]	'
Beginning Balance	$3,733
Acquisitions	3
Dispositions	-40
Subsequent payments/adjustments	-1
Ending Balance	3,695
Retail	'
Goodwill [Line Items]	'
Beginning Balance	1,007
Acquisitions	0
Dispositions	0
Subsequent payments/adjustments	0
Ending Balance	1,007
Employer Group	'
Goodwill [Line Items]	'
Beginning Balance	363
Acquisitions	0
Dispositions	0
Subsequent payments/adjustments	0
Ending Balance	363
Healthcare Services	'
Goodwill [Line Items]	'
Beginning Balance	2,271
Acquisitions	3
Dispositions	-40
Subsequent payments/adjustments	-1
Ending Balance	2,233
Other Businesses	'
Goodwill [Line Items]	'
Beginning Balance	92
Acquisitions	0
Dispositions	0
Subsequent payments/adjustments	0
Ending Balance	$92

Details_of_Intangible_Assets_I

Details of Intangible Assets Included in Other Long-Term Assets (Detail) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Weighted Average Life	'10 years 5 months 24 days	'
Cost	$1,063	$1,095
Accumulated Amortization	456	402
Net	607	693
Customer contracts/relationships	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Weighted Average Life	'9 years 9 months 18 days	'
Cost	764	792
Accumulated Amortization	349	310
Net	415	482
Trade names and technology	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Weighted Average Life	'13 years 2 months 12 days	'
Cost	198	200
Accumulated Amortization	54	40
Net	144	160
Provider contracts	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Weighted Average Life	'15 years 1 month	'
Cost	51	51
Accumulated Amortization	19	23
Net	32	28
Noncompetes And Other	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Weighted Average Life	'6 years 7 months	'
Cost	50	52
Accumulated Amortization	34	29
Net	$16	$23

Schedule_of_Estimated_Amortiza

Schedule of Estimated Amortization Expense (Detail) (USD $)	Sep. 30, 2014
In Millions, unless otherwise specified
Goodwill and Intangible Assets Disclosure [Abstract]	'
2014	$112
2015	101
2016	94
2017	86
2018	79
2019	$67

Schedule_of_Details_Supporting

Schedule of Details Supporting Computation of Earnings Per Share (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, except Share data in Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]	'	'	'	'
Net income available for common stockholders	$290	$368	$1,002	$1,261
Weighted average outstanding shares of common stock used to compute basic earnings per common share	154,502	157,187	155,006	158,026
Shares used to compute diluted earnings per common share	156,230	158,907	156,641	159,611
Basic earnings per common share (in dollars per share)	$1.87	$2.34	$6.46	$7.98
Diluted earnings per common share (in dollars per share)	$1.85	$2.31	$6.39	$7.90
Number of antidilutive stock options and restricted stock excluded from computation	43	202	420	910
Employee Stock Options	'	'	'	'
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]	'	'	'	'
Dilutive effect of employee stock options and restricted stock	203	289	233	341
Restricted Stock	'	'	'	'
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]	'	'	'	'
Dilutive effect of employee stock options and restricted stock	1,525	1,431	1,402	1,244

Schedule_of_Details_of_Dividen

Schedule of Details of Dividend Payments (Detail) (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012
Equity [Abstract]	'	'	'	'	'	'	'	'
Record Date	30-Sep-14	30-Jun-14	31-Mar-14	31-Dec-13	30-Sep-13	28-Jun-13	28-Mar-13	31-Dec-12
Payment Date	31-Oct-14	25-Jul-14	25-Apr-14	31-Jan-14	25-Oct-13	26-Jul-13	26-Apr-13	25-Jan-13
Amount per Share	$0.28	$0.28	$0.27	$0.27	$0.27	$0.27	$0.26	$0.26
Total Amount	$43	$43	$42	$42	$42	$42	$41	$42

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (USD $)

3 Months Ended

9 Months Ended

1 Months Ended

9 Months Ended

1 Months Ended

9 Months Ended

1 Months Ended

Share data in Millions, except Per Share data, unless otherwise specified

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Oct. 31, 2014

Sep. 30, 2014

Sep. 30, 2013

Apr. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Nov. 06, 2014

Nov. 07, 2014

Net unrealized gains on our investment securities

Net unrealized gains on our investment securities

Additional liability that would exist on closed block of long-term care policies assuming unrealized gains on investments backing such products were realized and reinvested at current yields

Additional liability that would exist on closed block of long-term care policies assuming unrealized gains on investments backing such products were realized and reinvested at current yields

Subsequent Event

Prior Authorization

Prior Authorization

Prior Authorization

September 2014 Share Repurchase Authorization

September 2014 Share Repurchase Authorization

September 2014 Share Repurchase Authorization

September 2014 Share Repurchase Authorization

Subsequent Event

Subsequent Event

Equity, Class of Treasury Stock [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Dividends per common share (in dollars per share)

$0.28

$0.27

$0.83

$0.80

'

'

'

'

'

$0.28

'

'

'

'

'

'

'

Share repurchase authorization

'

'

'

'

'

'

'

'

'

'

'

'

$1,000,000,000

$2,000,000,000

$2,000,000,000

'

'

Remaining authorized amount

'

'

'

'

'

'

'

'

'

'

'

'

816,000,000

'

'

'

1,870,000,000

Expiration date of new authorization

'

'

'

'

'

'

'

'

'

'

'

'

'

'

31-Dec-16

'

'

Shares repurchased in open market

'

'

'

'

'

'

'

'

'

'

1.6

3.78

'

'

0.27

0.77

'

Value of shares repurchased

'

'

'

'

'

'

'

'

'

'

195,000,000

301,000,000

'

'

35,000,000

100,000,000

'

Shares repurchased in open market, average price

'

'

'

'

'

'

'

'

'

'

$121.68

$79.79

'

'

$128.34

$130.50

'

Share repurchase authorization

'

'

'

'

'

'

'

'

'

'

'

'

'

'In September 2014, the Board of Directors replaced a previous share repurchase authorization of up to $1 billion (of which $816 million remained unused) with a new authorization for repurchases of up to $2 billion of our common shares exclusive of shares repurchased in connection with employee stock plans, expiring on December 31, 2016.

'

'

'

Common shares acquired in connection with employee stock plans, shares

'

'

0.4

0.3

'

'

'

'

'

'

'

'

'

'

'

'

'

Common shares acquired in connection with employee stock plans, amount

'

'

40,000,000

24,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Accumulated other comprehensive income

$233,000,000

'

$233,000,000

'

$158,000,000

$286,000,000

$158,000,000

$53,000,000

$0

'

'

'

'

'

'

'

'

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'	'	'	'
Effective Income Tax Rate	47.50%	37.20%	46.80%	36.00%
Percentage of Increase in effective tax rate	'	'	10.00%	'
Limitations on deductibility of excess annual employee compensation as mandated by health insurance reforms	'	'	'	$500,000

DEBT_Schedule_of_Longterm_Debt

DEBT - Schedule of Long-term Debt Outstanding (Details) (USD $)

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2013

Dec. 31, 2008

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Oct. 31, 2014

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Subsequent Event

$500 million, 6.45% due June 1, 2016

$500 million, 6.45% due June 1, 2016

$500 million, 7.20% due June 15, 2018

$500 million, 7.20% due June 15, 2018

$300 million, 6.30% due August 1, 2018

$300 million, 6.30% due August 1, 2018

$400 million, 2.625% due October 1, 2019

$400 million, 2.625% due October 1, 2019

$600 million, 3.15% due December 1, 2022

$600 million, 3.15% due December 1, 2022

$600 million, 3.85% due October 1, 2024

$600 million, 3.85% due October 1, 2024

$250 million, 8.15% due June 15, 2038

$250 million, 8.15% due June 15, 2038

$400 million, 4.625% due December 1, 2042

$400 million, 4.625% due December 1, 2042

$750 million, 4.95% due October 1, 2044

$750 million, 4.95% due October 1, 2044

Senior Notes

$500 million, 6.45% due June 1, 2016

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stated interest rate

'

'

'

'

'

'

6.45%

6.45%

7.20%

7.20%

6.30%

6.30%

2.63%

0.00%

3.15%

3.15%

3.85%

0.00%

8.15%

8.15%

4.63%

4.63%

4.95%

0.00%

'

Face amount

'

'

'

'

'

'

$500,000,000

$500,000,000

$500,000,000

$500,000,000

$300,000,000

$300,000,000

$400,000,000

$0

$600,000,000

$600,000,000

$600,000,000

$0

$250,000,000

$250,000,000

$400,000,000

$400,000,000

$750,000,000

$0

'

Total debt

4,338,000,000

2,600,000,000

4,338,000,000

4,338,000,000

2,600,000,000

'

512,000,000

517,000,000

505,000,000

505,000,000

312,000,000

314,000,000

400,000,000

0

598,000,000

598,000,000

599,000,000

0

266,000,000

266,000,000

400,000,000

400,000,000

746,000,000

0

'

Less current portion of long-term debt

512,000,000

0

512,000,000

512,000,000

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total long-term debt

'

'

3,826,000,000

3,826,000,000

2,600,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Proceeds from issuance of debt, net of underwriters' discount and commission and offering expenses

'

'

1,730,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Redemption price, percentage

'

'

'

100.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100.00%

Extinguishment of debt, amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

560,000,000

Loss on extinguishment of debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

37,000,000

Unamortized discount (premium)

'

'

$45,000,000

$45,000,000

$54,000,000

$103,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$12,000,000

DEBT_Credit_Agreement_Details

DEBT - Credit Agreement (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014	Nov. 06, 2014	Oct. 31, 2014
			Credit Agreement	Credit Agreement	Credit Agreement	Credit Agreement	Credit Agreement	Subsequent Event	Subsequent Event
			Line of Credit	Line of Credit	London Interbank Offered Rate (LIBOR)	Minimum	Maximum	Commercial Paper	Commercial Paper
			Revolving Credit Facility	Letter of Credit	Line of Credit	London Interbank Offered Rate (LIBOR)	London Interbank Offered Rate (LIBOR)
					Revolving Credit Facility	Line of Credit	Line of Credit
						Revolving Credit Facility	Revolving Credit Facility
Line of Credit Facility [Line Items]	'	'	'	'	'	'	'	'	'
Term	'	'	'5 years	'	'	'	'	'	'
Maximum borrowing capacity	'	'	$1,000,000,000	'	'	'	'	'	$1,000,000,000
Interest rate spread	'	'	'	'	1.10%	0.90%	1.50%	'	'
Facility fee (percentage)	'	'	'	'	0.15%	0.10%	0.25%	'	'
Minimum level of net worth required	'	'	7,600,000,000	'	'	'	'	'	'
Actual net worth	10,125,000,000	9,316,000,000	10,100,000,000	'	'	'	'	'	'
Required maximum leverage ratio	'	'	3	'	'	'	'	'	'
Actual leverage ratio	'	'	1.8	'	'	'	'	'	'
Uncommitted incremental loan facility	'	'	250,000,000	'	'	'	'	'	'
Line of credit, outstanding borrowings	'	'	0	'	'	'	'	'	'
Letters of credit outstanding	'	'	'	5,000,000	'	'	'	'	'
Remaining borrowing capacity	'	'	995,000,000	'	'	'	'	'	'
Amount outstanding	'	'	'	'	'	'	'	$150,000,000	'

Guarantees_and_Contingencies_A

Guarantees and Contingencies - Additional Information (Detail)	9 Months Ended	0 Months Ended	9 Months Ended
	Sep. 30, 2014	Jun. 26, 2013	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014
	New Tricare South Region Contract	Puerto Rico Health Insurance Administration Contracts East Southeast And Southwest Regions	Military Services	Medicare	Medicaid
Loss Contingencies [Line Items]	'	'	'	'	'
Percentage of premiums and services revenue	'	'	1.00%	73.00%	2.00%
Contract term, years	'5 years	'3 years	'	'	'
Contract expiration date	31-Mar-17	30-Jun-13	'	'	'

Segment_Information_Additional

Segment Information - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
			Segment
Segment Reporting [Abstract]	'	'	'	'
Number of reportable segments	'	'	3	'
Member co-share amounts and government subsidies	$2,600,000,000	$2,000,000,000	$6,800,000,000	$5,200,000,000
Depreciation and amortization classified as benefit expense	$27,000,000	$23,000,000	$79,000,000	$69,000,000

Segment_Information_by_Segment

Segment Information by Segment (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	$11,607	$9,698	$34,274	$29,267
Services	536	528	1,620	1,581
Total revenues - external customers	12,143	10,226	35,894	30,848
Investment income	95	93	278	278
Total revenues	12,238	10,319	36,172	31,126
Benefits	9,666	8,075	28,417	24,361
Operating costs	1,898	1,540	5,518	4,447
Depreciation and amortization	85	83	246	243
Total operating expenses	11,649	9,698	34,181	29,051
Income from operations	589	621	1,991	2,075
Interest expense	38	35	108	105
Income (loss) before income taxes	551	586	1,883	1,970
Medicare Advantage	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	7,889	6,745	23,574	20,403
Medicare Stand Alone Prescription Drug Plan	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	806	742	2,612	2,292
Medicare	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	8,695	7,487	26,186	22,695
Fully-Insured	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	2,261	1,570	6,348	4,675
Specialty	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	341	327	1,016	978
Military Services	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	5	6	15	22
Medicaid And Other	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	305	308	709	897
Provider	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Services	308	316	916	943
ASO And Other	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Services	202	195	632	599
Pharmacy	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Services	26	17	72	39
Intersegment revenues	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total revenues	-4,841	-3,729	-13,811	-10,793
Intersegment revenues | Retail	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total revenues	0	0	0	0
Intersegment revenues | Employer Group	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total revenues	22	14	57	37
Intersegment revenues | Healthcare Services	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total revenues	4,819	3,715	13,754	10,756
Intersegment revenues | Other Businesses	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total revenues	0	0	0	0
Intersegment revenues | Services	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total revenues	-3,873	-3,013	-11,059	-8,743
Intersegment revenues | Services | Retail	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total revenues	0	0	0	0
Intersegment revenues | Services | Employer Group	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total revenues	22	14	57	37
Intersegment revenues | Services | Healthcare Services	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total revenues	3,851	2,999	11,002	8,706
Intersegment revenues | Services | Other Businesses	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total revenues	0	0	0	0
Intersegment revenues | Products	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total revenues	-968	-716	-2,752	-2,050
Intersegment revenues | Products | Retail	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total revenues	0	0	0	0
Intersegment revenues | Products | Employer Group	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total revenues	0	0	0	0
Intersegment revenues | Products | Healthcare Services	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total revenues	968	716	2,752	2,050
Intersegment revenues | Products | Other Businesses	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total revenues	0	0	0	0
Operating Segments | Retail	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	8,597	6,714	25,271	20,384
Services	10	3	37	7
Total revenues - external customers	8,607	6,717	25,308	20,391
Investment income	19	19	56	55
Total revenues	8,626	6,736	25,364	20,446
Benefits	7,201	5,647	21,371	17,272
Operating costs	1,063	718	2,968	1,971
Depreciation and amortization	40	33	112	97
Total operating expenses	8,304	6,398	24,451	19,340
Income from operations	322	338	913	1,106
Interest expense	0	0	0	0
Income (loss) before income taxes	322	338	913	1,106
Operating Segments | Employer Group	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	2,992	2,746	8,946	8,191
Services	90	90	263	265
Total revenues - external customers	3,082	2,836	9,209	8,456
Investment income	11	10	32	31
Total revenues	3,115	2,860	9,298	8,524
Benefits	2,589	2,316	7,417	6,728
Operating costs	487	443	1,478	1,299
Depreciation and amortization	26	25	75	75
Total operating expenses	3,102	2,784	8,970	8,102
Income from operations	13	76	328	422
Interest expense	0	0	0	0
Income (loss) before income taxes	13	76	328	422
Operating Segments | Healthcare Services	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Services	328	327	971	967
Total revenues - external customers	328	327	971	967
Investment income	0	0	0	0
Total revenues	5,147	4,042	14,725	11,723
Benefits	0	0	0	0
Operating costs	4,908	3,856	14,024	11,223
Depreciation and amortization	37	37	108	109
Total operating expenses	4,945	3,893	14,132	11,332
Income from operations	202	149	593	391
Interest expense	0	0	0	0
Income (loss) before income taxes	202	149	593	391
Operating Segments | Other Businesses	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	18	238	57	692
Services	108	108	349	342
Total revenues - external customers	126	346	406	1,034
Investment income	15	15	45	45
Total revenues	141	361	451	1,079
Benefits	27	230	82	668
Operating costs	96	103	301	347
Depreciation and amortization	4	5	12	13
Total operating expenses	127	338	395	1,028
Income from operations	14	23	56	51
Interest expense	0	0	0	0
Income (loss) before income taxes	14	23	56	51
Operating Segments | Medicare Advantage | Retail	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	6,508	5,552	19,443	16,860
Operating Segments | Medicare Advantage | Employer Group	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	1,381	1,193	4,131	3,543
Operating Segments | Medicare Advantage | Healthcare Services	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Operating Segments | Medicare Advantage | Other Businesses	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Operating Segments | Medicare Stand Alone Prescription Drug Plan | Retail	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	804	740	2,606	2,286
Operating Segments | Medicare Stand Alone Prescription Drug Plan | Employer Group	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	2	2	6	6
Operating Segments | Medicare Stand Alone Prescription Drug Plan | Healthcare Services	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Operating Segments | Medicare Stand Alone Prescription Drug Plan | Other Businesses	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Operating Segments | Medicare | Retail	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	7,312	6,292	22,049	19,146
Operating Segments | Medicare | Employer Group	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	1,383	1,195	4,137	3,549
Operating Segments | Medicare | Healthcare Services	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Operating Segments | Medicare | Other Businesses	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Operating Segments | Fully-Insured | Retail	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	926	292	2,363	856
Operating Segments | Fully-Insured | Employer Group	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	1,335	1,278	3,985	3,819
Operating Segments | Fully-Insured | Healthcare Services	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Operating Segments | Fully-Insured | Other Businesses	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Operating Segments | Specialty | Retail	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	67	54	192	155
Operating Segments | Specialty | Employer Group	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	274	273	824	823
Operating Segments | Specialty | Healthcare Services	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Operating Segments | Specialty | Other Businesses	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Operating Segments | Military Services | Retail	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Operating Segments | Military Services | Employer Group	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Operating Segments | Military Services | Healthcare Services	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Operating Segments | Military Services | Other Businesses	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	5	6	15	22
Operating Segments | Medicaid And Other | Retail	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	292	76	667	227
Operating Segments | Medicaid And Other | Employer Group	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Operating Segments | Medicaid And Other | Healthcare Services	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Operating Segments | Medicaid And Other | Other Businesses	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	13	232	42	670
Operating Segments | Provider | Retail	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Services	0	0	0	0
Operating Segments | Provider | Employer Group	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Services	6	6	17	15
Operating Segments | Provider | Healthcare Services	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Services	302	310	899	928
Operating Segments | Provider | Other Businesses	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Services	0	0	0	0
Operating Segments | ASO And Other | Retail	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Services	10	3	37	7
Operating Segments | ASO And Other | Employer Group	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Services	84	84	246	250
Operating Segments | ASO And Other | Healthcare Services	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Services	0	0	0	0
Operating Segments | ASO And Other | Other Businesses	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Services	108	108	349	342
Operating Segments | Pharmacy | Retail	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Services	0	0	0	0
Operating Segments | Pharmacy | Employer Group	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Services	0	0	0	0
Operating Segments | Pharmacy | Healthcare Services	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Services	26	17	72	39
Operating Segments | Pharmacy | Other Businesses	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Services	0	0	0	0
Eliminations/Corporate	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Services	0	0	0	0
Total revenues - external customers	0	0	0	0
Investment income	50	49	145	147
Total revenues	-4,791	-3,680	-13,666	-10,646
Benefits	-151	-118	-453	-307
Operating costs	-4,656	-3,580	-13,253	-10,393
Depreciation and amortization	-22	-17	-61	-51
Total operating expenses	-4,829	-3,715	-13,767	-10,751
Income from operations	38	35	101	105
Interest expense	38	35	108	105
Income (loss) before income taxes	0	0	-7	0
Eliminations/Corporate | Medicare Advantage	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Eliminations/Corporate | Medicare Stand Alone Prescription Drug Plan	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Eliminations/Corporate | Medicare	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Eliminations/Corporate | Fully-Insured	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Eliminations/Corporate | Specialty	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Eliminations/Corporate | Military Services	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Eliminations/Corporate | Medicaid And Other	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Premiums	0	0	0	0
Eliminations/Corporate | Provider	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Services	0	0	0	0
Eliminations/Corporate | ASO And Other	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Services	0	0	0	0
Eliminations/Corporate | Pharmacy	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Services	$0	$0	$0	$0