Humana (HUM) 10-Q 7 May 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2014
Document Information [Line Items]	'
Document Type	'10-Q
Amendment Flag	'false
Document Period End Date	31-Mar-14
Document Fiscal Year Focus	'2014
Document Fiscal Period Focus	'Q1
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	154,784,234

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$1,662	$1,138
Investment securities	8,248	8,090
Receivables, less allowance for doubtful accounts of $118 in each of 2014 and 2013:	1,460	950
Other current assets	2,605	2,122
Total current assets	13,975	12,300
Property and equipment, net	1,244	1,218
Long-term investment securities	1,800	1,710
Goodwill	3,699	3,733
Other long-term assets	1,848	1,774
Total assets	22,566	20,735
Current liabilities:	'	'
Benefits payable	4,432	3,893
Trade accounts payable and accrued expenses	2,752	1,821
Book overdraft	267	403
Unearned revenues	263	206
Total current liabilities	7,714	6,323
Long-term debt	2,598	2,600
Future policy benefits payable	2,199	2,207
Other long-term liabilities	330	289
Total liabilities	12,841	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; 197,498,599 shares issued at March 31, 2014 and 196,275,506 shares issued at December 31, 2013	33	33
Capital in excess of par value	2,333	2,267
Retained earnings	9,266	8,942
Accumulated other comprehensive income	226	158
Treasury stock, at cost, 42,714,365 shares at March 31, 2014 and 42,245,097 shares at December 31, 2013	-2,133	-2,084
Total stockholders' equity	9,725	9,316
Total liabilities and stockholders' equity	$22,566	$20,735

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, except Share data, unless otherwise specified
Receivables, allowance for doubtful accounts	$118	$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	197,498,599	196,275,506
Treasury stock, shares	42,714,365	42,245,097

Condensed_Consolidated_Stateme

Condensed Consolidated Statements Of Income (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Revenues:	'	'
Premiums	$11,083	$9,868
Services	538	525
Investment income	91	93
Total revenues	11,712	10,486
Operating expenses:	'	'
Benefits	9,124	8,195
Operating costs	1,785	1,446
Depreciation and amortization	82	80
Total operating expenses	10,991	9,721
Income from operations	721	765
Interest expense	35	35
Income before income taxes	686	730
Provision for income taxes	318	257
Net income	$368	$473
Basic earnings per common share	$2.37	$2.97
Diluted earnings per common share	$2.35	$2.95
Dividends per common share	$0.27	$0.26

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements Of Comprehensive Income (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Net income	$368	$473
Other comprehensive income (loss):	'	'
Change in gross unrealized investment gains/losses	108	-87
Effect of income taxes	-39	32
Total change in unrealized investment gains/losses, net of tax	69	-55
Reclassification adjustment for net realized gains included in investment income	-1	-5
Effect of income taxes	0	2
Total reclassification adjustment, net of tax	-1	-3
Other comprehensive income (loss), net of tax	68	-58
Comprehensive income	$436	$415

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements Of Cash Flows (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities	'	'
Net income	$368	$473
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Net realized capital gains	-1	-5
Stock-based compensation	33	32
Depreciation and amortization	107	102
Benefit for deferred income taxes	-26	0
Changes in operating assets and liabilities, net of effect of businesses acquired:	'	'
Receivables	-524	-588
Other assets	-566	-130
Benefits payable	539	311
Other liabilities	684	190
Unearned revenues	57	13
Other, net	0	14
Net cash provided by operating activities	671	412
Cash flows from investing activities	'	'
Acquisitions, net of cash acquired	-6	-5
Proceeds from sale of business	72	0
Purchases of property and equipment	-106	-90
Purchases of investment securities	-507	-783
Maturities of investment securities	258	294
Proceeds from sales of investment securities	118	192
Net cash used in investing activities	-171	-392
Cash flows from financing activities	'	'
Receipts (withdrawals) from contract deposits, net	220	236
Change in book overdraft	-136	-34
Common stock repurchases	-49	-94
Dividends paid	-44	-42
Excess tax benefit from stock-based compensation	8	1
Proceeds from stock option exercises and other	25	5
Net cash provided by financing activities	24	72
Increase in cash and cash equivalents	524	92
Cash and cash equivalents at beginning of period	1,138	1,306
Cash and cash equivalents at end of period	1,662	1,398
Supplemental cash flow disclosures:	'	'
Interest payments	10	10
Income tax payments, net	$12	$1

BASIS_OF_PRESENTATION

BASIS OF PRESENTATION	3 Months Ended
	Mar. 31, 2014
BASIS OF PRESENTATION	'
	1. 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. We refer to the Form 10-K 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 the Company considers in preparing its 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 12 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 expect to pay the federal government approximately $548 million for the annual health insurance industry fee attributed to calendar year 2014, in accordance with the Health Care Reform Law. We have recorded a liability for this fee in other current liabilities with a corresponding deferred cost in other current assets in our condensed consolidated financial statements. Amortization of the deferred cost resulted in operating cost expense of approximately $137 million for the three months ended March 31, 2014 and a remaining deferred cost asset balance of approximately $411 million at March 31, 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, which collectively represented approximately 16% of our total premiums and services revenue for the three months ended March 31, 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 in 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. Risk corridor payments from HHS will be limited to the extent of the risk corridor collections received by HHS over the duration of the program.
	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 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 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, 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 three months ended March 31, 2014, we recorded operating costs of $18 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 $10 million and recorded ceded benefits of $18 million in our condensed consolidated statements of income for the three months ended March 31, 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 March 31, 2014. No such amounts were recorded in our condensed consolidated balance sheet at December 31, 2013. The risk adjustment, risk corridor, and reinsurance recoverable settlements include amounts classified as long-term because settlement associated with the 2014 provision exceeds 12 months at March 31, 2014.
		31-Mar-14
		Risk			Risk			Reinsurance			Reinsurance
		Adjustment			Corridor			Contribution			Recoverables
		Settlement			Settlement
	Trade accounts payable and accrued expenses	$	0		$	0			(28	)	$	0
	Other long-term assets		25			16			0			18
	Other long-term liabilities		(2	)		(3	)		0			0
	Net long-term asset		23			13			0			18
	Total net asset (liability)	$	23		$	13		$	(28	)	$	18
	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 $4 million higher than claims payments for the three months ended March 31, 2014.

RECENTLY_ISSUED_ACCOUNTING_PRO

RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS	3 Months Ended
	Mar. 31, 2014
RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS	'
	2. 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.
	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	3 Months Ended
	Mar. 31, 2014
ACQUISITIONS	'
	3. 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 and is deductible for tax purposes. The other intangible assets, which primarily consist of customer contracts and technology, have a weighted average useful life of 9.3 years. The purchase price allocation is preliminary, subject to completion of valuation analyses, including, for example, refining assumptions used to calculate the fair value of other intangible assets.
	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	3 Months Ended
	Mar. 31, 2014
INVESTMENT SECURITIES	'
	4. INVESTMENT SECURITIES
	Investment securities classified as current and long-term were as follows at March 31, 2014 and December 31, 2013, respectively:
		Amortized		Gross			Gross			Fair Value
		Cost		Unrealized			Unrealized
				Gains			Losses
		(in millions)
	March 31, 2014
	U.S. Treasury and other U.S. government corporations and agencies:
	U.S. Treasury and agency obligations	$	517	$	7		$	(4	)	$	520
	Mortgage-backed securities		1,870		37			(35	)		1,872
	Tax-exempt municipal securities		3,067		116			(17	)		3,166
	Mortgage-backed securities:
	Residential		21		0			(1	)		20
	Commercial		656		20			(11	)		665
	Asset-backed securities		49		1			0			50
	Corporate debt securities		3,493		275			(13	)		3,755
	Total debt securities	$	9,673	$	456		$	(81	)	$	10,048
	December 31, 2013
	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		0			0			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 March 31, 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)
	March 31, 2014
	U.S. Treasury and other U.S. government corporations and agencies:
	U.S. Treasury and agency obligations	$	212	$	(4	)	$	3		$	0		$	215	$	(4	)
	Mortgage-backed securities		1,145		(34	)		20			(1	)		1,165		(35	)
	Tax-exempt municipal securities		413		(13	)		115			(4	)		528		(17	)
	Mortgage-backed securities:
	Residential		5		0			1			(1	)		6		(1	)
	Commercial		148		(3	)		152			(8	)		300		(11	)
	Asset-backed securities		35		0			0			0			35		0
	Corporate debt securities		333		(11	)		35			(2	)		368		(13	)
	Total debt securities	$	2,291	$	(65	)	$	326		$	(16	)	$	2,617	$	(81	)
	December 31, 2013
	U.S. Treasury and other U.S. government corporations and agencies:
	U.S. Treasury and agency obligations	$	231	$	(6	)	$	5		$	0		$	236	$	(6	)
	Mortgage-backed securities		1,076		(47	)		21			(1	)		1,097		(48	)
	Tax-exempt municipal securities		693		(28	)		57			(5	)		750		(33	)
	Mortgage-backed securities:
	Residential		6		0			1			0			7		0
	Commercial		270		(8	)		40			(1	)		310		(9	)
	Asset-backed securities		35		(1	)		0			0			35		(1	)
	Corporate debt securities		594		(28	)		17			(2	)		611		(30	)
	Total debt securities	$	2,905	$	(118	)	$	141		$	(9	)	$	3,046	$	(127	)
	Approximately 95% of our debt securities were investment-grade quality, with a weighted average credit rating of AA- by S&P at March 31, 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 March 31, 2014, 6% 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 12%. In addition, 18% 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 March 31, 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 March 31, 2014.
	The percentage of corporate securities associated with the financial services industry was 22% at March 31, 2014 and 23% at December 31, 2013.
	All issuers of securities we own that were trading at an unrealized loss at March 31, 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 and tighter liquidity conditions in the current markets than when the securities were purchased. At March 31, 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 March 31, 2014.
	The detail of realized gains (losses) related to investment securities and included within investment income was as follows for the three months ended March 31, 2014 and 2013:
		For the three months
		ended March 31,
	2014		2013
	(in millions)
Gross realized gains	$	1	$	6
Gross realized losses		0		(1	)
Net realized capital gains	$	1	$	5
There were no material other-than-temporary impairments for the three months ended March 31, 2014 or 2013.
The contractual maturities of debt securities available for sale at March 31, 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	$	477	$	483
Due after one year through five years		2,114		2,214
Due after five years through ten years		2,533		2,663
Due after ten years		1,953		2,081
Mortgage and asset-backed securities		2,596		2,607
Total debt securities	$	9,673	$	10,048

FAIR_VALUE

FAIR VALUE	3 Months Ended
	Mar. 31, 2014
FAIR VALUE	'
	5. FAIR VALUE
	Financial Assets
	The following table summarizes our fair value measurements at March 31, 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)
	31-Mar-14
	Cash equivalents	$	1,197	$	1,197	$	0	$	0
	Debt securities:
	U.S. Treasury and other U.S. government corporations and agencies:
	U.S. Treasury and agency obligations		520		0		520		0
	Mortgage-backed securities		1,872		0		1,872		0
	Tax-exempt municipal securities		3,166		0		3,153		13
	Mortgage-backed securities:
	Residential		20		0		20		0
	Commercial		665		0		665		0
	Asset-backed securities		50		0		49		1
	Corporate debt securities		3,755		0		3,732		23
	Total debt securities		10,048		0		10,011		37
	Total invested assets	$	11,245	$	1,197	$	10,011	$	37
	31-Dec-13
	Cash equivalents	$	876	$	876	$	0	$	0
	Debt securities:
	U.S. Treasury and other U.S. government corporations and agencies:
	U.S. Treasury and agency obligations		584		0		584		0
	Mortgage-backed securities		1,820		0		1,820		0
	Tax-exempt municipal securities		2,971		0		2,958		13
	Mortgage-backed securities:
	Residential		22		0		22		0
	Commercial		673		0		673		0
	Asset-backed securities		63		0		62		1
	Corporate debt securities		3,667		0		3,644		23
	Total debt securities		9,800		0		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 months ended March 31, 2014 or March 31, 2013.
	Our Level 3 assets had a fair value of $37 million at March 31, 2014, or less than 0.4% of our total invested assets. During the three months ended March 31, 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 March 31,
		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		0		0		0		0			0		0
	Unrealized in other		0		0		0		1			0		1
	comprehensive income
	Purchases		0		0		0		0			0		0
	Sales		0		0		0		0			0		0
	Settlements		0		0		0		(1	)		0		(1	)
	Balance at March 31	$	24	$	13	$	37	$	25		$	13	$	38
	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 was $2,598 million at March 31, 2014 and $2,600 million at December 31, 2013. The fair value of our long-term debt was $2,815 million at March 31, 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 months ended March 31, 2014 or 2013.

MEDICARE_PART_D

MEDICARE PART D	3 Months Ended
	Mar. 31, 2014
MEDICARE PART D	'
	6. MEDICARE PART D
	We cover prescription drug benefits in accordance with Medicare Part D under multiple contracts with CMS. The accompanying condensed consolidated balance sheets include the following amounts associated with Medicare Part D at March 31, 2014 and December 31, 2013. The risk corridor settlement includes amounts classified as long-term because settlement associated with the 2014 provision will exceed 12 months at March 31, 2014.
		March 31, 2014						December 31, 2013
		Risk			CMS			Risk			CMS
		Corridor			Subsidies/			Corridor			Subsidies/
		Settlement			Discounts			Settlement			Discounts
		(in millions)
	Other current assets	$	44		$	880		$	45		$	743
	Trade accounts payable and accrued expenses		(45	)		(406	)		(71	)		(30	)
	Net current (liability) asset		(1	)		474			(26	)	$	713
	Other long-term assets		68			0			0			0
	Other long-term liabilities		(31	)		0			0			0
	Net long-term asset		37			0			0			0
	Total net asset (liability)	$	36		$	474		$	(26	)	$	713

GOODWILL_AND_OTHER_INTANGIBLE_

GOODWILL AND OTHER INTANGIBLE ASSETS	3 Months Ended
	Mar. 31, 2014
GOODWILL AND OTHER INTANGIBLE ASSETS	'
	7. 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 three months ended March 31, 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		0		0		6			0		6
	Dispositions		0		0		(40	)		0		(40	)
	Balance at March 31, 2014	$	1,007	$	363	$	2,237		$	92	$	3,699
	The following table presents details of our other intangible assets included in other long-term assets in the accompanying condensed consolidated balance sheets at March 31, 2014 and December 31, 2013:
		Weighted		31-Mar-14							31-Dec-13
		Average				Accumulated								Accumulated
		Life		Cost		Amortization			Net		Cost			Amortization		Net
		(in millions)
	Other intangible assets:
	Customer contracts/relationships		9.8 yrs	$	764	$	310		$	454	$	792		$	310	$	482
	Trade names and technology		13.2 yrs		198		43			155		200			40		160
	Provider contracts		16.5 yrs		45		18			27		51			23		28
	Noncompetes and other		6.5 yrs		50		29			21		52			29		23
	Total other intangible assets		10.4 yrs	$	1,057	$	400		$	657	$	1,095		$	402	$	693
	Amortization expense for other intangible assets was approximately $28 million for the three months ended March 31, 2014 and 2013. 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		100
	2016		92
	2017		85
	2018		78
	2019		67

EARNINGS_PER_COMMON_SHARE_COMP

EARNINGS PER COMMON SHARE COMPUTATION	3 Months Ended
	Mar. 31, 2014
EARNINGS PER COMMON SHARE COMPUTATION	'
	8. EARNINGS PER COMMON SHARE COMPUTATION
	Detail supporting the computation of basic and diluted earnings per common share was as follows for the three months ended March 31, 2014 and 2013:
		For the three months ended
		March 31,
		2014		2013
		(dollars in millions, except
		per common share
		results; number of shares
		in thousands)
	Net income available for common stockholders	$	368	$	473
	Weighted average outstanding shares of common stock used to compute basic earnings per common share		155,091		158,917
	Dilutive effect of:
	Employee stock options		268		384
	Restricted stock		1,288		1,102
	Shares used to compute diluted earnings per common share		156,647		160,403
	Basic earnings per common share	$	2.37	$	2.97
	Diluted earnings per common share	$	2.35	$	2.95
	Number of antidilutive stock options and restricted stock excluded from computation		972		1,683

STOCKHOLDERS_EQUITY

STOCKHOLDERS' EQUITY	3 Months Ended
	Mar. 31, 2014
STOCKHOLDERS' EQUITY	'
	9. STOCKHOLDERS’ EQUITY
	Dividends
	The following table provides details of dividend payments in 2013 and 2014 under our Board approved quarterly cash dividend policy:
	Record Date	Payment	Amount		Total
		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
	In April 2014, the Board of Directors declared a cash dividend of $0.28 per share payable on July 25, 2014 to stockholders of record on June 30, 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 April 2014, the Board of Directors replaced a previous share repurchase authorization of up to $1 billion (of which $569 million remained unused) with a new authorization for repurchases of up to $1 billion of our common shares exclusive of shares repurchased in connection with employee stock plans, expiring on June 30, 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 three months ended March 31, 2014, we repurchased 0.1 million shares in open market transactions for $11 million at an average price of $113.44 under a previous share repurchase authorization. During the three months ended March 31, 2013, we repurchased 1.21 million shares in open market transactions for $81 million at an average price of $67.60 under a previous share repurchase authorization. As of May 7, 2014, the remaining authorized amount under the new authorization totaled $1 billion.
	In connection with employee stock plans, we acquired 0.4 million common shares for $38 million and 0.2 million common shares for $13 million during the three months ended March 31, 2014 and 2013, respectively.
	Accumulated Other Comprehensive Income
	Accumulated other comprehensive income included net unrealized gains on our investment securities of $238 million at March 31, 2014 and $158 million at December 31, 2013. In addition, accumulated other comprehensive income included $12 million at March 31, 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 10-K for further discussion of our long-term care insurance policies.

INCOME_TAXES

INCOME TAXES	3 Months Ended
	Mar. 31, 2014
INCOME TAXES	'
	10. INCOME TAXES
	The effective income tax rate was 46.4% for the three months ended March 31, 2014, compared to 35.2% for the three months ended March 31, 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 9 percentage points for the three months ended March 31, 2014. In addition, the effective tax for the three months ended March 31, 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.

GUARANTEES_AND_CONTINGENCIES

GUARANTEES AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2014
GUARANTEES AND CONTINGENCIES	'
	11. GUARANTEES AND CONTINGENCIES
	Government Contracts
	Our Medicare products, which accounted for approximately 75% of our total premiums and services revenue for the three months ended March 31, 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. Our bids for the 2015 contract year are due by June 2, 2014.
	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.
	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 one of our Medicare Advantage contracts had 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 audits will have a material adverse effect on our results of operations, financial position, or cash flows.
	At March 31, 2014, our military services business, which accounted for approximately 1% of our total premiums and services revenue for the three months ended March 31, 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 three months ended March 31, 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 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. We are responding to the information requests.
	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	3 Months Ended
	Mar. 31, 2014
SEGMENT INFORMATION	'
	12. 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 $1.9 billion and $1.5 billion for the three months ended March 31, 2014 and 2013, 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 $25 million and $22 million for the three months ended March 31, 2014 and 2013, 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 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 included with intersegment eliminations in the tables presenting segment results below.
	Our segment results were as follows for the three months ended March 31, 2014 and 2013, respectively:
		Retail		Employer		Healthcare		Other		Eliminations/			Consolidated
				Group		Services		Businesses		Corporate
		(in millions)
	Three months ended March 31, 2014
	Revenues - external customers
	Premiums:
	Medicare Advantage	$	6,460	$	1,384	$	0	$	0	$	0		$	7,844
	Medicare stand-alone PDP		863		2		0		0		0			865
	Total Medicare		7,323		1,386		0		0		0			8,709
	Fully-insured		525		1,329		0		0		0			1,854
	Specialty		59		275		0		0		0			334
	Military services		0		0		0		6		0			6
	Medicaid and other		169		0		0		11		0			180
	Total premiums		8,076		2,990		0		17		0			11,083
	Services revenue:
	Provider		0		5		290		0		0			295
	ASO and other		14		81		0		127		0			222
	Pharmacy		0		0		21		0		0			21
	Total services revenue		14		86		311		127		0			538
	Total revenues - external customers		8,090		3,076		311		144		0			11,621
	Intersegment revenues
	Services		0		19		3,454		0		(3,473	)		0
	Products		0		0		846		0		(846	)		0
	Total intersegment revenues		0		19		4,300		0		(4,319	)		0
	Investment income		19		10		0		15		47			91
	Total revenues		8,109		3,105		4,611		159		(4,272	)		11,712
	Operating expenses:
	Benefits		6,887		2,356		0		28		(147	)		9,124
	Operating costs		923		499		4,390		102		(4,129	)		1,785
	Depreciation and amortization		37		24		36		4		(19	)		82
	Total operating expenses		7,847		2,879		4,426		134		(4,295	)		10,991
	Income from operations		262		226		185		25		23			721
	Interest expense		0		0		0		0		35			35
	Income (loss) before income taxes	$	262	$	226	$	185	$	25	$	(12	)	$	686
		Retail		Employer		Healthcare		Other		Eliminations/			Consolidated
				Group		Services		Businesses		Corporate
		(in millions)
	Three months ended March 31, 2013
	Revenues - external customers
	Premiums:
	Medicare Advantage	$	5,736	$	1,190	$	0	$	0	$	0		$	6,926
	Medicare stand-alone PDP		761		2		0		0		0			763
	Total Medicare		6,497		1,192		0		0		0			7,689
	Fully-insured		279		1,268		0		0		0			1,547
	Specialty		49		275		0		0		0			324
	Military services		0		0		0		11		0			11
	Medicaid and other		79		0		0		218		0			297
	Total premiums		6,904		2,735		0		229		0			9,868
	Services revenue:
	Provider		0		4		306		0		0			310
	ASO and other		2		84		0		120		0			206
	Pharmacy		0		0		9		0		0			9
	Total services revenue		2		88		315		120		0			525
	Total revenues - external customers		6,906		2,823		315		349		0			10,393
	Intersegment revenues
Services		0		11		2,801		0		(2,812	)		0
Products		0		0		654		0		(654	)		0
Total intersegment revenues		0		11		3,455		0		(3,466	)		0
Investment income		18		11		0		15		49			93
Total revenues		6,924		2,845		3,770		364		(3,417	)		10,486
Operating expenses:
Benefits		5,929		2,177		0		187		(98	)		8,195
Operating costs		613		433		3,616		115		(3,331	)		1,446
Depreciation and amortization		32		23		36		4		(15	)		80
Total operating expenses		6,574		2,633		3,652		306		(3,444	)		9,721
Income from operations		350		212		118		58		27			765
Interest expense		0		0		0		0		35			35
Income (loss) before income taxes	$	350	$	212	$	118	$	58	$	(8	)	$	730

BASIS_OF_PRESENTATION_Tables

BASIS OF PRESENTATION (Tables)	3 Months Ended
	Mar. 31, 2014
Risk Adjustment, Risk Corridor, and Reinsurance Recoverable Settlements	'
	The risk adjustment, risk corridor, and reinsurance recoverable settlements include amounts classified as long-term because settlement associated with the 2014 provision exceeds 12 months at March 31, 2014.
		March 31, 2014
		Risk			Risk			Reinsurance			Reinsurance
		Adjustment			Corridor			Contribution			Recoverables
		Settlement			Settlement
	Trade accounts payable and accrued expenses	$	0		$	0			(28	)	$	0
	Other long-term assets		25			16			0			18
	Other long-term liabilities		(2	)		(3	)		0			0
	Net long-term asset		23			13			0			18
	Total net asset (liability)	$	23		$	13		$	(28	)	$	18

INVESTMENT_SECURITIES_Tables

INVESTMENT SECURITIES (Tables)	3 Months Ended
	Mar. 31, 2014
Schedule of Investment Securities Classified as Current and Long-Term	'
	Investment securities classified as current and long-term were as follows at March 31, 2014 and December 31, 2013, respectively:
		Amortized		Gross			Gross			Fair Value
		Cost		Unrealized			Unrealized
				Gains			Losses
		(in millions)
	March 31, 2014
	U.S. Treasury and other U.S. government corporations and agencies:
	U.S. Treasury and agency obligations	$	517	$	7		$	(4	)	$	520
	Mortgage-backed securities		1,870		37			(35	)		1,872
	Tax-exempt municipal securities		3,067		116			(17	)		3,166
	Mortgage-backed securities:
	Residential		21		0			(1	)		20
	Commercial		656		20			(11	)		665
	Asset-backed securities		49		1			0			50
	Corporate debt securities		3,493		275			(13	)		3,755
	Total debt securities	$	9,673	$	456		$	(81	)	$	10,048
	December 31, 2013
	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		0			0			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 March 31, 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)
	March 31, 2014
	U.S. Treasury and other U.S. government corporations and agencies:
	U.S. Treasury and agency obligations	$	212	$	(4	)	$	3		$	0		$	215	$	(4	)
	Mortgage-backed securities		1,145		(34	)		20			(1	)		1,165		(35	)
	Tax-exempt municipal securities		413		(13	)		115			(4	)		528		(17	)
	Mortgage-backed securities:
	Residential		5		0			1			(1	)		6		(1	)
	Commercial		148		(3	)		152			(8	)		300		(11	)
	Asset-backed securities		35		0			0			0			35		0
	Corporate debt securities		333		(11	)		35			(2	)		368		(13	)
	Total debt securities	$	2,291	$	(65	)	$	326		$	(16	)	$	2,617	$	(81	)
	December 31, 2013
	U.S. Treasury and other U.S. government corporations and agencies:
	U.S. Treasury and agency obligations	$	231	$	(6	)	$	5		$	0		$	236	$	(6	)
	Mortgage-backed securities		1,076		(47	)		21			(1	)		1,097		(48	)
	Tax-exempt municipal securities		693		(28	)		57			(5	)		750		(33	)
	Mortgage-backed securities:
	Residential		6		0			1			0			7		0
	Commercial		270		(8	)		40			(1	)		310		(9	)
	Asset-backed securities		35		(1	)		0			0			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 months ended March 31, 2014 and 2013:
		For the three months
		ended March 31,
		2014		2013
		(in millions)
	Gross realized gains	$	1	$	6
	Gross realized losses		0		(1	)
	Net realized capital gains	$	1	$	5
Schedule of Contractual Maturity of Debt Securities Available for Sale	'
	The contractual maturities of debt securities available for sale at March 31, 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	$	477	$	483
	Due after one year through five years		2,114		2,214
	Due after five years through ten years		2,533		2,663
	Due after ten years		1,953		2,081
	Mortgage and asset-backed securities		2,596		2,607
	Total debt securities	$	9,673	$	10,048

FAIR_VALUE_Tables

FAIR VALUE (Tables)	3 Months Ended
	Mar. 31, 2014
Financial Assets Measured at Fair Value on Recurring Basis	'
	The following table summarizes our fair value measurements at March 31, 2014 and December 31, 2013, respectively, for financial assets measured at fair value on a recurring basis:
				Fair Value Measurements Using
		Fair Value		Quoted Prices		Other		Unobservable
				in Active		Observable		Inputs
				Markets		Inputs		(Level 3)
				(Level 1)		(Level 2)
		(in millions)
	March 31, 2014
	Cash equivalents	$	1,197	$	1,197	$	0	$	0
	Debt securities:
	U.S. Treasury and other U.S. government corporations and agencies:
	U.S. Treasury and agency obligations		520		0		520		0
	Mortgage-backed securities		1,872		0		1,872		0
	Tax-exempt municipal securities		3,166		0		3,153		13
	Mortgage-backed securities:
	Residential		20		0		20		0
	Commercial		665		0		665		0
	Asset-backed securities		50		0		49		1
	Corporate debt securities		3,755		0		3,732		23
	Total debt securities		10,048		0		10,011		37
	Total invested assets	$	11,245	$	1,197	$	10,011	$	37
	December 31, 2013
	Cash equivalents	$	876	$	876	$	0	$	0
	Debt securities:
	U.S. Treasury and other U.S. government corporations and agencies:
	U.S. Treasury and agency obligations		584		0		584		0
	Mortgage-backed securities		1,820		0		1,820		0
	Tax-exempt municipal securities		2,971		0		2,958		13
	Mortgage-backed securities:
	Residential		22		0		22		0
	Commercial		673		0		673		0
	Asset-backed securities		63		0		62		1
	Corporate debt securities		3,667		0		3,644		23
	Total debt securities		9,800		0		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 months ended March 31, 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 March 31,
		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		0		0		0		0			0		0
	Unrealized in other		0		0		0		1			0		1
	comprehensive income
	Purchases		0		0		0		0			0		0
	Sales		0		0		0		0			0		0
	Settlements		0		0		0		(1	)		0		(1	)
	Balance at March 31	$	24	$	13	$	37	$	25		$	13	$	38

MEDICARE_PART_D_Tables

MEDICARE PART D (Tables)	3 Months Ended
	Mar. 31, 2014
Balance Sheet Amounts Associated With Medicare Part D	'
	The accompanying condensed consolidated balance sheets include the following amounts associated with Medicare Part D at March 31, 2014 and December 31, 2013. The risk corridor settlement includes amounts classified as long-term because settlement associated with the 2014 provision will exceed 12 months at March 31, 2014.
		March 31, 2014						December 31, 2013
		Risk			CMS			Risk			CMS
		Corridor			Subsidies/			Corridor			Subsidies/
		Settlement			Discounts			Settlement			Discounts
		(in millions)
	Other current assets	$	44		$	880		$	45		$	743
	Trade accounts payable and accrued expenses		(45	)		(406	)		(71	)		(30	)
	Net current (liability) asset		(1	)		474			(26	)	$	713
	Other long-term assets		68			0			0			0
	Other long-term liabilities		(31	)		0			0			0
	Net long-term asset		37			0			0			0
	Total net asset (liability)	$	36		$	474		$	(26	)	$	713

GOODWILL_AND_OTHER_INTANGIBLE_1

GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)	3 Months Ended
	Mar. 31, 2014
Changes in Carrying Amount of Goodwill By Reportable Segments	'
	Changes in the carrying amount of goodwill for our reportable segments for the three months ended March 31, 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		0		0		6			0		6
	Dispositions		0		0		(40	)		0		(40	)
	Balance at March 31, 2014	$	1,007	$	363	$	2,237		$	92	$	3,699
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 March 31, 2014 and December 31, 2013:
		Weighted		31-Mar-14							31-Dec-13
		Average				Accumulated								Accumulated
		Life		Cost		Amortization			Net		Cost			Amortization		Net
		(in millions)
	Other intangible assets:
	Customer contracts/relationships		9.8 yrs	$	764	$	310		$	454	$	792		$	310	$	482
	Trade names and technology		13.2 yrs		198		43			155		200			40		160
	Provider contracts		16.5 yrs		45		18			27		51			23		28
	Noncompetes and other		6.5 yrs		50		29			21		52			29		23
	Total other intangible assets		10.4 yrs	$	1,057	$	400		$	657	$	1,095		$	402	$	693
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		100
	2016		92
	2017		85
	2018		78
	2019		67

EARNINGS_PER_COMMON_SHARE_COMP1

EARNINGS PER COMMON SHARE COMPUTATION (Tables)	3 Months Ended
	Mar. 31, 2014
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 months ended March 31, 2014 and 2013:
		For the three months ended
		March 31,
		2014		2013
		(dollars in millions, except
		per common share
		results; number of shares
		in thousands)
	Net income available for common stockholders	$	368	$	473
	Weighted average outstanding shares of common stock used to compute basic earnings per common share		155,091		158,917
	Dilutive effect of:
	Employee stock options		268		384
	Restricted stock		1,288		1,102
	Shares used to compute diluted earnings per common share		156,647		160,403
	Basic earnings per common share	$	2.37	$	2.97
	Diluted earnings per common share	$	2.35	$	2.95
	Number of antidilutive stock options and restricted stock excluded from computation		972		1,683

STOCKHOLDERS_EQUITY_Tables

STOCKHOLDERS' EQUITY (Tables)	3 Months Ended
	Mar. 31, 2014
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 Date	Payment	Amount		Total
		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

SEGMENT_INFORMATION_Tables

SEGMENT INFORMATION (Tables)	3 Months Ended
	Mar. 31, 2014
Schedule of Segment Reporting Information, By Segment	'
	Our segment results were as follows for the three months ended March 31, 2014 and 2013, respectively:
		Retail		Employer		Healthcare		Other		Eliminations/			Consolidated
				Group		Services		Businesses		Corporate
		(in millions)
	Three months ended March 31, 2014
	Revenues - external customers
	Premiums:
	Medicare Advantage	$	6,460	$	1,384	$	0	$	0	$	0		$	7,844
	Medicare stand-alone PDP		863		2		0		0		0			865
	Total Medicare		7,323		1,386		0		0		0			8,709
	Fully-insured		525		1,329		0		0		0			1,854
	Specialty		59		275		0		0		0			334
	Military services		0		0		0		6		0			6
	Medicaid and other		169		0		0		11		0			180
	Total premiums		8,076		2,990		0		17		0			11,083
	Services revenue:
	Provider		0		5		290		0		0			295
	ASO and other		14		81		0		127		0			222
	Pharmacy		0		0		21		0		0			21
	Total services revenue		14		86		311		127		0			538
	Total revenues - external customers		8,090		3,076		311		144		0			11,621
	Intersegment revenues
	Services		0		19		3,454		0		(3,473	)		0
	Products		0		0		846		0		(846	)		0
	Total intersegment revenues		0		19		4,300		0		(4,319	)		0
	Investment income		19		10		0		15		47			91
	Total revenues		8,109		3,105		4,611		159		(4,272	)		11,712
	Operating expenses:
	Benefits		6,887		2,356		0		28		(147	)		9,124
	Operating costs		923		499		4,390		102		(4,129	)		1,785
	Depreciation and amortization		37		24		36		4		(19	)		82
	Total operating expenses		7,847		2,879		4,426		134		(4,295	)		10,991
	Income from operations		262		226		185		25		23			721
	Interest expense		0		0		0		0		35			35
	Income (loss) before income taxes	$	262	$	226	$	185	$	25	$	(12	)	$	686
		Retail		Employer		Healthcare		Other		Eliminations/			Consolidated
				Group		Services		Businesses		Corporate
		(in millions)
	Three months ended March 31, 2013
	Revenues - external customers
	Premiums:
	Medicare Advantage	$	5,736	$	1,190	$	0	$	0	$	0		$	6,926
	Medicare stand-alone PDP		761		2		0		0		0			763
	Total Medicare		6,497		1,192		0		0		0			7,689
	Fully-insured		279		1,268		0		0		0			1,547
	Specialty		49		275		0		0		0			324
	Military services		0		0		0		11		0			11
	Medicaid and other		79		0		0		218		0			297
	Total premiums		6,904		2,735		0		229		0			9,868
	Services revenue:
	Provider		0		4		306		0		0			310
	ASO and other		2		84		0		120		0			206
	Pharmacy		0		0		9		0		0			9
	Total services revenue		2		88		315		120		0			525
	Total revenues - external customers		6,906		2,823		315		349		0			10,393
	Intersegment revenues
	Services		0		11		2,801		0		(2,812	)		0
	Products		0		0		654		0		(654	)		0
	Total intersegment revenues		0		11		3,455		0		(3,466	)		0
	Investment income		18		11		0		15		49			93
	Total revenues		6,924		2,845		3,770		364		(3,417	)		10,486
	Operating expenses:
	Benefits		5,929		2,177		0		187		(98	)		8,195
Operating costs		613		433		3,616		115		(3,331	)		1,446
Depreciation and amortization		32		23		36		4		(15	)		80
Total operating expenses		6,574		2,633		3,652		306		(3,444	)		9,721
Income from operations		350		212		118		58		27			765
Interest expense		0		0		0		0		35			35
Income (loss) before income taxes	$	350	$	212	$	118	$	58	$	(8	)	$	730

Basis_of_Presentation_Addition

Basis of Presentation - Additional Information (Detail) (USD $)	3 Months Ended			12 Months Ended	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014
			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 for calendar year 2014 to be paid in September 2014	'	'	$548	'	'
Operating cost expense associated with amortization of deferred cost	'	'	137	'	'
Deferred cost asset	'	'	411	0	'
Percentage of premiums and services revenue applicable to risk spreading programs	'	'	'	'	16.00%
Payment of risk adjustment audit by health and human services in 2014 or 2015, first two years of the program	'	'	0	'	'
Operating costs associated with transitional reinsurance contributions	'	'	18	'	'
Ceded premiums	'	'	10	0	'
Ceded benefits	'	'	18	0	'
Payments due to HHS under risk adjustment, remittance period	'	'	'30 days	'	'
Proceed for health care cost sharing subsidies for low-income individual members	$1,900	$1,500	$4	'	'

Risk_Adjustment_Risk_Corridor_

Risk Adjustment, Risk Corridor and Reinsurance Recoverable Settlements (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Effects of Risk Spreading Premium Stabilization Programs [Line Items]	'	'
Trade accounts payable and accrued expenses	($2,752)	($1,821)
Other long-term assets	1,848	1,774
Other long-term liabilities	-330	-289
Risk Adjustment Settlement | Health Care Reform	'	'
Effects of Risk Spreading Premium Stabilization Programs [Line Items]	'	'
Trade accounts payable and accrued expenses	0	'
Other long-term assets	25	'
Other long-term liabilities	-2	'
Net long-term asset	23	'
Total net asset (liability)	23	'
Risk Corridor Settlements | Health Care Reform	'	'
Effects of Risk Spreading Premium Stabilization Programs [Line Items]	'	'
Trade accounts payable and accrued expenses	0	'
Other long-term assets	16	'
Other long-term liabilities	-3	'
Net long-term asset	13	'
Total net asset (liability)	13	'
Reinsurance Contribution | Health Care Reform	'	'
Effects of Risk Spreading Premium Stabilization Programs [Line Items]	'	'
Trade accounts payable and accrued expenses	-28	'
Other long-term assets	0	'
Other long-term liabilities	0	'
Net long-term asset	0	'
Total net asset (liability)	-28	'
Reinsurance Recoverable | Health Care Reform	'	'
Effects of Risk Spreading Premium Stabilization Programs [Line Items]	'	'
Trade accounts payable and accrued expenses	0	'
Other long-term assets	18	'
Other long-term liabilities	0	'
Net long-term asset	18	'
Total net asset (liability)	$18	'

Acquisitions_Additional_Inform

Acquisitions - Additional Information (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]	'	'
Goodwill acquired	$3,699	$3,733
Other intangible assets useful life, years	'10 years 4 months 24 days	'
American Eldercare Inc.	'	'
Business Acquisition [Line Items]	'	'
Date of acquisition	6-Sep-13	'
Goodwill acquired	76	'
Amount allocated to other intangible assets	$75	'
Other intangible assets useful life, years	'9 years 3 months 18 days	'

Schedule_of_Investment_Securit

Schedule of Investment Securities Classified as Current and Long-Term (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Investment [Line Items]	'	'
Amortized Cost	$9,673	$9,550
Gross Unrealized Gains	456	377
Gross Unrealized Losses	-81	-127
Total debt securities, Fair Value	10,048	9,800
Debt Securities | Tax-exempt municipal securities	'	'
Investment [Line Items]	'	'
Amortized Cost	3,067	2,911
Gross Unrealized Gains	116	93
Gross Unrealized Losses	-17	-33
Total debt securities, Fair Value	3,166	2,971
Debt Securities | Residential Mortgage-Backed Securities	'	'
Investment [Line Items]	'	'
Amortized Cost	21	22
Gross Unrealized Gains	0	0
Gross Unrealized Losses	-1	0
Total debt securities, Fair Value	20	22
Debt Securities | Commercial Mortgage-Backed Securities	'	'
Investment [Line Items]	'	'
Amortized Cost	656	662
Gross Unrealized Gains	20	20
Gross Unrealized Losses	-11	-9
Total debt securities, Fair Value	665	673
Debt Securities | Asset-backed Securities	'	'
Investment [Line Items]	'	'
Amortized Cost	49	63
Gross Unrealized Gains	1	1
Gross Unrealized Losses	0	-1
Total debt securities, Fair Value	50	63
Debt Securities | Corporate Debt Securities	'	'
Investment [Line Items]	'	'
Amortized Cost	3,493	3,474
Gross Unrealized Gains	275	223
Gross Unrealized Losses	-13	-30
Total debt securities, Fair Value	3,755	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	517	584
Gross Unrealized Gains	7	6
Gross Unrealized Losses	-4	-6
Total debt securities, Fair Value	520	584
Debt Securities | U.S. Treasury And Other U.S. Government Corporations And Agencies | Mortgage-Backed Securities	'	'
Investment [Line Items]	'	'
Amortized Cost	1,870	1,834
Gross Unrealized Gains	37	34
Gross Unrealized Losses	-35	-48
Total debt securities, Fair Value	$1,872	$1,820

Schedule_of_Gross_Unrealized_L

Schedule of Gross Unrealized Losses and Fair Values of Securities (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Investment [Line Items]	'	'
Less than 12 months, Fair Value	$2,291	$2,905
Less than 12 months, Gross Unrealized Losses	-65	-118
12 months or more, Fair Value	326	141
12 months or more, Gross Unrealized Losses	-16	-9
Total, Fair Value	2,617	3,046
Total, Gross Unrealized Losses	-81	-127
Debt Securities | Tax-exempt municipal securities	'	'
Investment [Line Items]	'	'
Less than 12 months, Fair Value	413	693
Less than 12 months, Gross Unrealized Losses	-13	-28
12 months or more, Fair Value	115	57
12 months or more, Gross Unrealized Losses	-4	-5
Total, Fair Value	528	750
Total, Gross Unrealized Losses	-17	-33
Debt Securities | Residential Mortgage-Backed Securities	'	'
Investment [Line Items]	'	'
Less than 12 months, Fair Value	5	6
Less than 12 months, Gross Unrealized Losses	0	0
12 months or more, Fair Value	1	1
12 months or more, Gross Unrealized Losses	-1	0
Total, Fair Value	6	7
Total, Gross Unrealized Losses	-1	0
Debt Securities | Commercial Mortgage-Backed Securities	'	'
Investment [Line Items]	'	'
Less than 12 months, Fair Value	148	270
Less than 12 months, Gross Unrealized Losses	-3	-8
12 months or more, Fair Value	152	40
12 months or more, Gross Unrealized Losses	-8	-1
Total, Fair Value	300	310
Total, Gross Unrealized Losses	-11	-9
Debt Securities | Asset-backed Securities	'	'
Investment [Line Items]	'	'
Less than 12 months, Fair Value	35	35
Less than 12 months, Gross Unrealized Losses	0	-1
12 months or more, Fair Value	0	0
12 months or more, Gross Unrealized Losses	0	0
Total, Fair Value	35	35
Total, Gross Unrealized Losses	0	-1
Debt Securities | Corporate Debt Securities	'	'
Investment [Line Items]	'	'
Less than 12 months, Fair Value	333	594
Less than 12 months, Gross Unrealized Losses	-11	-28
12 months or more, Fair Value	35	17
12 months or more, Gross Unrealized Losses	-2	-2
Total, Fair Value	368	611
Total, Gross Unrealized Losses	-13	-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	212	231
Less than 12 months, Gross Unrealized Losses	-4	-6
12 months or more, Fair Value	3	5
12 months or more, Gross Unrealized Losses	0	0
Total, Fair Value	215	236
Total, Gross Unrealized Losses	-4	-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	1,145	1,076
Less than 12 months, Gross Unrealized Losses	-34	-47
12 months or more, Fair Value	20	21
12 months or more, Gross Unrealized Losses	-1	-1
Total, Fair Value	1,165	1,097
Total, Gross Unrealized Losses	($35)	($48)

Investment_Securities_Addition

Investment Securities - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]	'	'	'
Percentage of debt securities considered to be of investment-grade	95.00%	'	'
Percentage of tax-exempt municipal securities classified as pre-refunded	6.00%	'	'
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	12.00%	'	'
Percentage of tax-exempt securities insured by bond insurers	18.00%	'	'
Residential and commercial mortgage-backed securities, percentage of collateral consisting of prime loans	99.00%	'	'
Percentage of corporate securities associated with financial services industry	22.00%	'	23.00%
Other-than-temporary impairments	$0	$0	'

Schedule_of_Realized_Gains_Los

Schedule of Realized Gains (Losses) Related to Investment Securities Included Within Investment Income (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Gain (Loss) on Investments [Line Items]	'	'
Gross realized gains	$1	$6
Gross realized losses	0	-1
Net realized capital gains	$1	$5

Schedule_of_Contractual_Maturi

Schedule of Contractual Maturities of Debt Securities Available for Sale (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Available-for-sale Securities, Debt Maturities [Abstract]	'	'
Due within one year, Amortized Cost	$477	'
Due after one year through five years, Amortized Cost	2,114	'
Due after five years through ten years, Amortized Cost	2,533	'
Due after ten years, Amortized Cost	1,953	'
Mortgage and asset-backed securities, Amortized Cost	2,596	'
Total debt securities, Amortized Cost	9,673	9,550
Due within one year, Fair Value	483	'
Due after one year through five years, Fair Value	2,214	'
Due after five years through ten years, Fair Value	2,663	'
Due after ten years, Fair Value	2,081	'
Mortgage and asset-backed securities, Fair Value	2,607	'
Total debt securities, Fair Value	$10,048	$9,800

Financial_Assets_Measured_at_F

Financial Assets Measured at Fair Value on Recurring Basis (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash equivalents, Fair Value	$1,197	$876
Total debt securities, Fair Value	10,048	9,800
Total invested assets	11,245	10,676
Debt Securities | Tax-exempt municipal securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	3,166	2,971
Debt Securities | Residential Mortgage-Backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	20	22
Debt Securities | Commercial Mortgage-Backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	665	673
Debt Securities | Asset-backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	50	63
Debt Securities | Corporate Debt Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	3,755	3,667
Debt Securities | 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	520	584
Debt Securities | 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	1,872	1,820
Quoted Prices in Active Markets for Identical Assets (Level 1)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash equivalents, Fair Value	1,197	876
Total debt securities, Fair Value	0	0
Total invested assets	1,197	876
Quoted Prices in Active Markets for Identical Assets (Level 1) | Debt Securities | 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) | Debt Securities | 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) | Debt Securities | 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) | Debt Securities | 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) | Debt Securities | 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) | Debt Securities | 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) | Debt Securities | 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)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash equivalents, Fair Value	0	0
Total debt securities, Fair Value	10,011	9,763
Total invested assets	10,011	9,763
Significant Other Observable Inputs (Level 2) | Debt Securities | Tax-exempt municipal securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	3,153	2,958
Significant Other Observable Inputs (Level 2) | Debt Securities | Residential Mortgage-Backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	20	22
Significant Other Observable Inputs (Level 2) | Debt Securities | Commercial Mortgage-Backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	665	673
Significant Other Observable Inputs (Level 2) | Debt Securities | Asset-backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	49	62
Significant Other Observable Inputs (Level 2) | Debt Securities | Corporate Debt Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	3,732	3,644
Significant Other Observable Inputs (Level 2) | Debt Securities | 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	520	584
Significant Other Observable Inputs (Level 2) | Debt Securities | 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	1,872	1,820
Significant Unobservable Inputs (Level 3)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash equivalents, Fair Value	0	0
Total debt securities, Fair Value	37	37
Total invested assets	37	37
Significant Unobservable Inputs (Level 3) | Debt Securities | 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) | Debt Securities | 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) | Debt Securities | 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) | Debt Securities | 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) | Debt Securities | Corporate Debt Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total debt securities, Fair Value	23	23
Significant Unobservable Inputs (Level 3) | Debt Securities | 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) | Debt Securities | 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

Fair_Value_Additional_Informat

Fair Value - Additional Information (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'	'	'
Transfers between Level 1 and Level 2	$0	'	$0	'
Level 3 assets fair value	37	37	38	38
Upper limit percentage of Level 3 assets to total invested assets	0.40%	'	'	'
Long-term debt, carrying value	2,598	2,600	'	'
Long-term debt, fair value	$2,815	$2,751	'	'

Changes_in_Fair_Value_of_Asset

Changes in Fair Value of Assets Measured Using Significant Unobservable Inputs (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Beginning Balance	$37	$38
Realized in earnings	0	0
Unrealized in other comprehensive income	0	1
Purchases	0	0
Sales	0	0
Settlements	0	-1
Ending Balance	37	38
Private Placement	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Beginning Balance	24	25
Realized in earnings	0	0
Unrealized in other comprehensive income	0	1
Purchases	0	0
Sales	0	0
Settlements	0	-1
Ending Balance	24	25
Auction Rate Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Beginning Balance	13	13
Realized in earnings	0	0
Unrealized in other comprehensive income	0	0
Purchases	0	0
Sales	0	0
Settlements	0	0
Ending Balance	$13	$13

Balance_Sheet_Amounts_Associat

Balance Sheet Amounts Associated With Medicare Part D (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Segment Reporting Information [Line Items]	'	'
Other current assets	$2,605	$2,122
Trade accounts payable and accrued expenses	-2,752	-1,821
Other long-term assets	1,848	1,774
Other long-term liabilities	-330	-289
Risk Corridor Settlements - Medicare Part D	'	'
Segment Reporting Information [Line Items]	'	'
Other current assets	44	45
Trade accounts payable and accrued expenses	-45	-71
Net current (liability) asset	-1	-26
Other long-term assets	68	0
Other long-term liabilities	-31	0
Net long-term asset	37	0
Total net asset (liability)	36	-26
CMS Subsidies/Discounts	'	'
Segment Reporting Information [Line Items]	'	'
Other current assets	880	743
Trade accounts payable and accrued expenses	-406	-30
Net current (liability) asset	474	713
Other long-term assets	0	0
Other long-term liabilities	0	0
Net long-term asset	0	0
Total net asset (liability)	$474	$713

Changes_in_Carrying_Amount_of_

Changes in Carrying Amount of Goodwill by Reportable Segments (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014
Goodwill [Line Items]	'
Beginning Balance	$3,733
Acquisitions	6
Dispositions	-40
Ending Balance	3,699
Retail	'
Goodwill [Line Items]	'
Beginning Balance	1,007
Acquisitions	0
Dispositions	0
Ending Balance	1,007
Employer Group	'
Goodwill [Line Items]	'
Beginning Balance	363
Acquisitions	0
Dispositions	0
Ending Balance	363
Health And Well-Being Services	'
Goodwill [Line Items]	'
Beginning Balance	2,271
Acquisitions	6
Dispositions	-40
Ending Balance	2,237
Other Businesses	'
Goodwill [Line Items]	'
Beginning Balance	92
Acquisitions	0
Dispositions	0
Ending Balance	$92

Details_of_Intangible_Assets_I

Details of Intangible Assets Included in Other Long-Term Assets (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Weighted Average Life	'10 years 4 months 24 days	'
Cost	$1,057	$1,095
Accumulated Amortization	400	402
Net	657	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	310	310
Net	454	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	43	40
Net	155	160
Provider contracts	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Weighted Average Life	'16 years 6 months	'
Cost	45	51
Accumulated Amortization	18	23
Net	27	28
Noncompetes And Other	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Weighted Average Life	'6 years 6 months	'
Cost	50	52
Accumulated Amortization	29	29
Net	$21	$23

Recovered_Sheet1

Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Goodwill And Other Intangible Assets [Line Items]	'	'
Amortization expense for other intangible assets	$28	$28

Schedule_of_Estimated_Amortiza

Schedule of Estimated Amortization Expense (Detail) (USD $)	Mar. 31, 2014
In Millions, unless otherwise specified
Expected Amortization Expense [Line Items]	'
2014	$112
2015	100
2016	92
2017	85
2018	78
2019	$67

Schedule_of_Details_Supporting

Schedule of Details Supporting Computation of Earnings Per Share (Detail) (USD $)	3 Months Ended
In Millions, except Share data in Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]	'	'
Net income available for common stockholders	$368	$473
Weighted average outstanding shares of common stock used to compute basic earnings per common share	155,091	158,917
Shares used to compute diluted earnings per common share	156,647	160,403
Basic earnings per common share	$2.37	$2.97
Diluted earnings per common share	$2.35	$2.95
Number of antidilutive stock options and restricted stock excluded from computation	972	1,683
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	268	384
Restricted Stock	'	'
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]	'	'
Dilutive effect of employee stock options and restricted stock	1,288	1,102

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	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012
Stockholders Equity Note [Line Items]	'	'	'	'	'	'
Record Date	31-Mar-14	31-Dec-13	30-Sep-13	28-Jun-13	28-Mar-13	31-Dec-12
Payment Date	25-Apr-14	31-Jan-14	25-Oct-13	26-Jul-13	26-Apr-13	25-Jan-13
Amount per Share	$0.27	$0.27	$0.27	$0.27	$0.26	$0.26
Total Amount	$42	$42	$42	$42	$41	$42

Stockholders_Equity_Additional

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

3 Months Ended

1 Months Ended

3 Months Ended

1 Months Ended

3 Months Ended

0 Months Ended

1 Months Ended

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

Mar. 31, 2014

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Apr. 30, 2014

Mar. 31, 2014

Mar. 31, 2013

Apr. 30, 2014

Mar. 31, 2014

7-May-14

Apr. 30, 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

New Authorization

New Authorization

New Authorization

Dividend Declared

Subsequent Event

Subsequent Event

Subsequent Event

Equity, Class of Treasury Stock [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash dividend declared

$0.27

'

'

'

$0.26

'

'

'

'

'

$0.28

'

'

'

'

'

'

Dividend payable date

25-Apr-14

31-Jan-14

25-Oct-13

26-Jul-13

26-Apr-13

25-Jan-13

'

'

'

'

25-Jul-14

'

'

'

'

'

'

Record Date

31-Mar-14

31-Dec-13

30-Sep-13

28-Jun-13

28-Mar-13

31-Dec-12

'

'

'

'

30-Jun-14

'

'

'

'

'

'

Expiration date of new authorization

'

'

'

'

'

'

'

'

'

'

'

'

'

'

30-Jun-16

'

'

Share repurchase authorization

'

'

'

'

'

'

'

'

'

'

'

'

'

$1,000,000,000

'

'

$1,000,000,000

Share repurchase authorization

'

'

'

'

'

'

'

'

'

'

'

'

'

'In April 2014, the Board of Directors replaced a previous share repurchase authorization of up to $1 billion (of which $569 million remained unused) with a new authorization for repurchases of up to $1 billion of our common shares exclusive of shares repurchased in connection with employee stock plans, expiring on June 30, 2016.

'

'

'

Shares repurchased in open market

'

'

'

'

'

'

'

'

'

'

'

0.1

1.21

'

'

'

'

Value of shares repurchased

'

'

'

'

'

'

'

'

'

'

'

11,000,000

81,000,000

'

'

'

'

Shares repurchased in open market, average price

'

'

'

'

'

'

'

'

'

'

'

$113.44

$67.60

'

'

'

'

Remaining authorized amount

'

'

'

'

'

'

'

'

'

'

'

'

'

569,000,000

'

1,000,000,000

'

Common shares acquired in connection with employee stock plans, shares

0.4

'

'

'

0.2

'

'

'

'

'

'

'

'

'

'

'

'

Common shares acquired in connection with employee stock plans, amount

38,000,000

'

'

'

13,000,000

'

'

'

'

'

'

'

'

'

'

'

'

Accumulated other comprehensive income

$226,000,000

$158,000,000

'

'

'

'

$238,000,000

$158,000,000

$12,000,000

$0

'

'

'

'

'

'

'

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Income Tax [Line Items]	'	'
Effective Income Tax Rate	46.40%	35.20%
Percentage of Increase in effective tax rate	9.00%	'
Limitations on deductibility of excess annual employee compensation as mandated by health insurance reforms	'	$500,000

Guarantees_and_Contingencies_A

Guarantees and Contingencies - Additional Information (Detail)	3 Months Ended	0 Months Ended	3 Months Ended
	Mar. 31, 2014	Jun. 26, 2013	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 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%	75.00%	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
	Mar. 31, 2014	Mar. 31, 2013
	Segment
Segment Reporting Information [Line Items]	'	'
Number of reportable segments	3	'
Member co-share amounts and government subsidies	$1,900,000,000	$1,500,000,000
Depreciation and amortization classified as benefit expense	$25,000,000	$22,000,000

Segment_Information_by_Segment

Segment Information by Segment (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]	'	'
Premiums	$11,083	$9,868
Services	538	525
Total revenues - external customers	11,621	10,393
Investment income	91	93
Total revenues	11,712	10,486
Benefits	9,124	8,195
Operating costs	1,785	1,446
Depreciation and amortization	82	80
Total operating expenses	10,991	9,721
Income from operations	721	765
Interest expense	35	35
Income (loss) before income taxes	686	730
Medicare Advantage	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	7,844	6,926
Medicare Stand Alone Prescription Drug Plan	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	865	763
Medicare	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	8,709	7,689
Fully-Insured	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	1,854	1,547
Specialty	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	334	324
Military Services	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	6	11
Medicaid And Other	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	180	297
Provider	'	'
Segment Reporting Information [Line Items]	'	'
Services	295	310
ASO And Other	'	'
Segment Reporting Information [Line Items]	'	'
Services	222	206
Pharmacy	'	'
Segment Reporting Information [Line Items]	'	'
Services	21	9
Intersegment revenues	'	'
Segment Reporting Information [Line Items]	'	'
Total revenues	-4,319	-3,466
Intersegment revenues | Retail	'	'
Segment Reporting Information [Line Items]	'	'
Total revenues	0	0
Intersegment revenues | Employer Group	'	'
Segment Reporting Information [Line Items]	'	'
Total revenues	19	11
Intersegment revenues | Healthcare Services	'	'
Segment Reporting Information [Line Items]	'	'
Total revenues	4,300	3,455
Intersegment revenues | Other Businesses	'	'
Segment Reporting Information [Line Items]	'	'
Total revenues	0	0
Intersegment revenues | Services	'	'
Segment Reporting Information [Line Items]	'	'
Total revenues	-3,473	-2,812
Intersegment revenues | Services | Retail	'	'
Segment Reporting Information [Line Items]	'	'
Total revenues	0	0
Intersegment revenues | Services | Employer Group	'	'
Segment Reporting Information [Line Items]	'	'
Total revenues	19	11
Intersegment revenues | Services | Healthcare Services	'	'
Segment Reporting Information [Line Items]	'	'
Total revenues	3,454	2,801
Intersegment revenues | Services | Other Businesses	'	'
Segment Reporting Information [Line Items]	'	'
Total revenues	0	0
Intersegment revenues | Products	'	'
Segment Reporting Information [Line Items]	'	'
Total revenues	-846	-654
Intersegment revenues | Products | Retail	'	'
Segment Reporting Information [Line Items]	'	'
Total revenues	0	0
Intersegment revenues | Products | Employer Group	'	'
Segment Reporting Information [Line Items]	'	'
Total revenues	0	0
Intersegment revenues | Products | Healthcare Services	'	'
Segment Reporting Information [Line Items]	'	'
Total revenues	846	654
Intersegment revenues | Products | Other Businesses	'	'
Segment Reporting Information [Line Items]	'	'
Total revenues	0	0
Operating Segments | Retail	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	8,076	6,904
Services	14	2
Total revenues - external customers	8,090	6,906
Investment income	19	18
Total revenues	8,109	6,924
Benefits	6,887	5,929
Operating costs	923	613
Depreciation and amortization	37	32
Total operating expenses	7,847	6,574
Income from operations	262	350
Interest expense	0	0
Income (loss) before income taxes	262	350
Operating Segments | Employer Group	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	2,990	2,735
Services	86	88
Total revenues - external customers	3,076	2,823
Investment income	10	11
Total revenues	3,105	2,845
Benefits	2,356	2,177
Operating costs	499	433
Depreciation and amortization	24	23
Total operating expenses	2,879	2,633
Income from operations	226	212
Interest expense	0	0
Income (loss) before income taxes	226	212
Operating Segments | Healthcare Services	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Services	311	315
Total revenues - external customers	311	315
Investment income	0	0
Total revenues	4,611	3,770
Benefits	0	0
Operating costs	4,390	3,616
Depreciation and amortization	36	36
Total operating expenses	4,426	3,652
Income from operations	185	118
Interest expense	0	0
Income (loss) before income taxes	185	118
Operating Segments | Other Businesses	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	17	229
Services	127	120
Total revenues - external customers	144	349
Investment income	15	15
Total revenues	159	364
Benefits	28	187
Operating costs	102	115
Depreciation and amortization	4	4
Total operating expenses	134	306
Income from operations	25	58
Interest expense	0	0
Income (loss) before income taxes	25	58
Operating Segments | Medicare Advantage | Retail	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	6,460	5,736
Operating Segments | Medicare Advantage | Employer Group	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	1,384	1,190
Operating Segments | Medicare Advantage | Healthcare Services	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Operating Segments | Medicare Advantage | Other Businesses	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Operating Segments | Medicare Stand Alone Prescription Drug Plan | Retail	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	863	761
Operating Segments | Medicare Stand Alone Prescription Drug Plan | Employer Group	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	2	2
Operating Segments | Medicare Stand Alone Prescription Drug Plan | Healthcare Services	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Operating Segments | Medicare Stand Alone Prescription Drug Plan | Other Businesses	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Operating Segments | Medicare | Retail	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	7,323	6,497
Operating Segments | Medicare | Employer Group	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	1,386	1,192
Operating Segments | Medicare | Healthcare Services	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Operating Segments | Medicare | Other Businesses	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Operating Segments | Fully-Insured | Retail	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	525	279
Operating Segments | Fully-Insured | Employer Group	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	1,329	1,268
Operating Segments | Fully-Insured | Healthcare Services	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Operating Segments | Fully-Insured | Other Businesses	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Operating Segments | Specialty | Retail	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	59	49
Operating Segments | Specialty | Employer Group	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	275	275
Operating Segments | Specialty | Healthcare Services	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Operating Segments | Specialty | Other Businesses	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Operating Segments | Military Services | Retail	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Operating Segments | Military Services | Employer Group	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Operating Segments | Military Services | Healthcare Services	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Operating Segments | Military Services | Other Businesses	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	6	11
Operating Segments | Medicaid And Other | Retail	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	169	79
Operating Segments | Medicaid And Other | Employer Group	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Operating Segments | Medicaid And Other | Healthcare Services	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Operating Segments | Medicaid And Other | Other Businesses	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	11	218
Operating Segments | Provider | Retail	'	'
Segment Reporting Information [Line Items]	'	'
Services	0	0
Operating Segments | Provider | Employer Group	'	'
Segment Reporting Information [Line Items]	'	'
Services	5	4
Operating Segments | Provider | Healthcare Services	'	'
Segment Reporting Information [Line Items]	'	'
Services	290	306
Operating Segments | Provider | Other Businesses	'	'
Segment Reporting Information [Line Items]	'	'
Services	0	0
Operating Segments | ASO And Other | Retail	'	'
Segment Reporting Information [Line Items]	'	'
Services	14	2
Operating Segments | ASO And Other | Employer Group	'	'
Segment Reporting Information [Line Items]	'	'
Services	81	84
Operating Segments | ASO And Other | Healthcare Services	'	'
Segment Reporting Information [Line Items]	'	'
Services	0	0
Operating Segments | ASO And Other | Other Businesses	'	'
Segment Reporting Information [Line Items]	'	'
Services	127	120
Operating Segments | Pharmacy | Retail	'	'
Segment Reporting Information [Line Items]	'	'
Services	0	0
Operating Segments | Pharmacy | Employer Group	'	'
Segment Reporting Information [Line Items]	'	'
Services	0	0
Operating Segments | Pharmacy | Healthcare Services	'	'
Segment Reporting Information [Line Items]	'	'
Services	21	9
Operating Segments | Pharmacy | Other Businesses	'	'
Segment Reporting Information [Line Items]	'	'
Services	0	0
Eliminations/Corporate	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Services	0	0
Total revenues - external customers	0	0
Investment income	47	49
Total revenues	-4,272	-3,417
Benefits	-147	-98
Operating costs	-4,129	-3,331
Depreciation and amortization	-19	-15
Total operating expenses	-4,295	-3,444
Income from operations	23	27
Interest expense	35	35
Income (loss) before income taxes	-12	-8
Eliminations/Corporate | Medicare Advantage	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Eliminations/Corporate | Medicare Stand Alone Prescription Drug Plan	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Eliminations/Corporate | Medicare	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Eliminations/Corporate | Fully-Insured	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Eliminations/Corporate | Specialty	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Eliminations/Corporate | Military Services	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Eliminations/Corporate | Medicaid And Other	'	'
Segment Reporting Information [Line Items]	'	'
Premiums	0	0
Eliminations/Corporate | Provider	'	'
Segment Reporting Information [Line Items]	'	'
Services	0	0
Eliminations/Corporate | ASO And Other	'	'
Segment Reporting Information [Line Items]	'	'
Services	0	0
Eliminations/Corporate | Pharmacy	'	'
Segment Reporting Information [Line Items]	'	'
Services	$0	$0