UnitedHealth (UNH) 10-K 8 Feb 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information Document - USD ($)	12 Months Ended
	Dec. 31, 2016	Jan. 31, 2017	Jun. 30, 2016
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Entitiy Registrant Name	UNITEDHEALTH GROUP INC
Entitiy Central Index Key	731,766
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Well known seasoned issuer	Yes
Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Common Stock, Shares Outstanding		951,165,192
Closing Share Price			$ 141.20
Public Float			$ 132,269,813,351

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 10,430	$ 10,923
Short-term investments	2,845	1,988
Accounts receivable, net of allowances of $514 and $333	8,152	6,523
Other current receivables, net of allowances of $409 and $138	7,499	6,801
Assets under management	3,105	2,998
Prepaid expenses and other current assets	1,848	2,406
Total current assets	33,879	31,639
Long-term investments	23,868	18,792
Property, equipment and capitalized software, net of accumulated depreciation and amortization of $3,749 and $3,173	5,901	4,861
Goodwill	47,584	44,453
Other intangible assets, net of accumulated amortization of $3,847 and $3,128	8,541	8,391
Other assets	3,037	3,118
Total assets	122,810	111,254	[1]
Current liabilities:
Medical costs payable	16,391	14,330
Accounts payable and accrued liabilities	13,361	11,994
Commercial paper and current maturities of long-term debt	7,193	6,634
Unearned revenues	1,968	2,142
Other current liabilities	10,339	7,798
Total current liabilities	49,252	42,898
Long-term debt, less current maturities	25,777	25,331
Future policy benefits	2,524	2,496
Deferred income taxes	2,761	3,587
Other liabilities	2,307	1,481
Total liabilities	82,621	75,793
Commitments and contingencies (Note 12)
Redeemable noncontrolling interests	2,012	1,736
Equity:
Preferred stock, $0.001 par value - 10 shares authorized; no shares issued or outstanding	0	0
Common stock, $0.01 par value - 3,000 shares authorized; 952 and 953 issued and outstanding	10	10
Additional paid-in capital	0	29
Retained earnings	40,945	37,125
Accumulated other comprehensive loss	(2,681)	(3,334)
Nonredeemable noncontrolling interest	(97)	(105)
Total equity	38,177	33,725
Total liabilities, redeemable noncontrolling interests and equity	$ 122,810	$ 111,254
[1]	(a)In the first quarter of 2016, the Company adopted ASU 2015-03, retrospectively as required. See Note 2 for more information on the adoption of ASU 2015-03.

Consolidated Balance Sheet (Par

Consolidated Balance Sheet (Parenthetical) - USD ($) shares in Millions, $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Allowance for doubtful accounts, accounts receivable	$ 514	$ 333
Allowance for doubtful accounts, other receivables	409	138
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	3,749	3,173
Finite-lived Intangible Assets, Accumulated Amortization	$ 3,847	$ 3,128
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	3,000	3,000
Common stock, shares issued	952	953
Common Stock, shares outstanding	952	953
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	10	10
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues:
Premiums	$ 144,118	$ 127,163	$ 115,302
Products	26,658	17,312	4,242
Services	13,236	11,922	10,151
Investment and other income	828	710	779
Total revenues	184,840	157,107	130,474
Operating costs:
Medical costs	117,038	103,875	93,633
Operating costs	28,401	24,312	21,263
Cost of products sold	24,416	16,206	3,826
Depreciation and amortization	2,055	1,693	1,478
Total operating costs	171,910	146,086	120,200
Earnings from operations	12,930	11,021	10,274
Interest expense	(1,067)	(790)	(618)
Earnings before income taxes	11,863	10,231	9,656
Provision for income taxes	(4,790)	(4,363)	(4,037)
Net earnings	7,073	5,868	5,619
Earnings attributable to noncontrolling interests	(56)	(55)	0
Net earnings attributable to UnitedHealth Group common shareholders	$ 7,017	$ 5,813	$ 5,619
Earnings per share attributable to UnitedHealth Group common shareholders:
Basic	$ 7.37	$ 6.10	$ 5.78
Diluted	$ 7.25	$ 6.01	$ 5.70
Basic weighted-average number of common shares outstanding	952	953	972
Dilutive effect of common share equivalents	16	14	14
Diluted weighted-average number of common shares outstanding	968	967	986
Anti-dilutive shares excluded from the calculation of dilutive effect of common share equivalents	3	8	6
Cash dividends declared per common share	$ 2.375	$ 1.875	$ 1.405

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net earnings	$ 7,073	$ 5,868	$ 5,619
Other comprehensive income (loss):
Gross unrealized (losses) gains on investment securities during the period	(73)	(123)	476
Income tax effect	26	44	(173)
Total unrealized (losses) gains, net of tax	(47)	(79)	303
Gross reclassification adjustment for net realized gains included in net earnings	(166)	(141)	(211)
Income tax effect	60	53	77
Total reclassification adjustment, net of tax	(106)	(88)	(134)
Total foreign currency translation gains (losses)	806	(1,775)	(653)
Other comprehensive income (loss)	653	(1,942)	(484)
Comprehensive income	7,726	3,926	5,135
Comprehensive income attributable to noncontrolling interests	(56)	(55)	0
Comprehensive income attributable to UnitedHealth Group common shareholders	$ 7,670	$ 3,871	$ 5,135

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Net Unrealized Gains (Losses) on Investments [Member]	Foreign Currency Translation Losses [Member]	Nonredeemable noncontrolling interests [Member]
Balance at Dec. 31, 2013	$ 32,149	$ 10	$ 0	$ 33,047	$ 54	$ (962)	$ 0
Balance (in shares) at Dec. 31, 2013		988
Net earnings attributable to UnitedHealth Group common shareholders	5,619			5,619
Net earnings including portion attributable to nonredeemable noncontrolling interest	5,619
Other comprehensive income (loss)	(484)				169	(653)
Issuances of common stock, and related tax effects (in shares)		15
Issuances of common stock, and related tax effects	146	$ 0	146
Share-based compensation, and related tax benefits	394		394
Common shares repurchases, shares		(49)
Common share repurchases	(4,008)	$ 0	(540)	(3,468)
Cash dividends paid on common shares	(1,362)			(1,362)
Balance at Dec. 31, 2014	32,454	$ 10	0	33,836	223	(1,615)	0
Balance (in shares) at Dec. 31, 2014		954
Net earnings attributable to UnitedHealth Group common shareholders	5,813			5,813
Net earnings attributable to nonredeemable noncontrolling interest							26
Net earnings including portion attributable to nonredeemable noncontrolling interest	5,839
Other comprehensive income (loss)	(1,942)				(167)	(1,775)
Issuances of common stock, and related tax effects (in shares)		10
Issuances of common stock, and related tax effects	127	$ 0	127
Share-based compensation, and related tax benefits	$ 589		589
Common shares repurchases, shares	(11)	(11)
Common share repurchases	$ (1,200)	$ 0	(462)	(738)
Cash dividends paid on common shares	(1,786)			(1,786)
Redeemable noncontrolling interests fair value and other adjustments	(225)		(225)
Acquisition of nonredeemable noncontrolling interest	9						9
Distributions to nonredeemable noncontrolling interest	(140)						(140)
Balance at Dec. 31, 2015	$ 33,725	$ 10	29	37,125	56	(3,390)	(105)
Balance (in shares) at Dec. 31, 2015	953	953
Cumulative Effect of New Accounting Pronouncement	$ 28			28
Net earnings attributable to UnitedHealth Group common shareholders	7,017			7,017
Net earnings attributable to nonredeemable noncontrolling interest							40
Net earnings including portion attributable to nonredeemable noncontrolling interest	7,057
Other comprehensive income (loss)	653				(153)	806
Issuances of common stock, and related tax effects (in shares)		9
Issuances of common stock, and related tax effects	191	$ 0	191
Share-based Compensation	$ 455		455
Common shares repurchases, shares	(10)	(10)
Common share repurchases	$ (1,280)	$ 0	(316)	(964)
Cash dividends paid on common shares	(2,261)			(2,261)
Acquisition of redeemable noncontrolling interest shares	(143)		(143)
Redeemable noncontrolling interests fair value and other adjustments	(216)		(216)
Distributions to nonredeemable noncontrolling interest	(32)						(32)
Balance at Dec. 31, 2016	$ 38,177	$ 10	$ 0	$ 40,945	$ (97)	$ (2,584)	$ (97)
Balance (in shares) at Dec. 31, 2016	952	952

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities
Net earnings	$ 7,073	$ 5,868	$ 5,619
Noncash items:
Depreciation and amortization	2,055	1,693	1,478
Deferred income taxes	81	(73)	(117)
Share-based compensation	485	406	364
Other, net	(82)	(235)	(298)
Net change in other operating items, net of effects from acquisitions and changes in AARP balances:
Accounts receivable	(1,357)	(591)	(911)
Other assets	(1,601)	(1,430)	(590)
Medical costs payable	1,849	2,585	484
Accounts payable and other liabilities	1,494	1,280	1,637
Unearned revenues	(202)	237	385
Cash flows from operating activities	9,795	9,740	8,051
Investing activities
Purchases of investments	(17,547)	(9,939)	(9,928)
Sales of investments	7,339	6,054	7,701
Maturities of investments	4,281	3,354	3,026
Cash paid for acquisitions, net of cash assumed	(1,760)	(16,164)	(1,923)
Purchases of property, equipment and capitalized software	(1,705)	(1,556)	(1,525)
Other, net	37	(144)	115
Cash flows used for investing activities	(9,355)	(18,395)	(2,534)
Financing activities
Acquisition of redeemable noncontrolling interest shares	(257)	(118)	0
Common share repurchases	(1,280)	(1,200)	(4,008)
Cash dividends paid	(2,261)	(1,786)	(1,362)
Proceeds from common stock issuances	429	402	462
Repayments of long-term debt	(2,596)	(1,041)	(812)
(Repayments of) proceeds from commercial paper, net	(382)	3,666	(794)
Proceeds from issuance of long-term debt	3,968	11,982	1,997
Customer funds administered	1,692	768	(638)
Other, net	(324)	(434)	(138)
Cash flows (used for) from financing activities	(1,011)	12,239	(5,293)
Effect of exchange rate changes on cash and cash equivalents	78	(156)	(5)
(Decrease) increase in cash and cash equivalents	(493)	3,428	219
Cash and cash equivalents, beginning of period	10,923	7,495	7,276
Cash and cash equivalents, end of period	10,430	10,923	7,495
Supplemental cash flow disclosures
Cash paid for interest	1,055	639	644
Cash paid for income taxes	$ 4,726	$ 4,401	$ 4,024

Description of Business (Notes)

Description of Business (Notes)	12 Months Ended
	Dec. 31, 2016
Nature of Operations [Text Block]	Description of Business UnitedHealth Group Incorporated (individually and together with its subsidiaries, “UnitedHealth Group” and “the Company”) is a diversified health and well-being company dedicated to helping people live healthier lives and helping to make the health system work better for everyone. Through its diversified family of businesses, the Company leverages core competencies in advanced, enabling technology; health care data, information and intelligence; and clinical care management and coordination to help meet the demands of the health system. These core competencies are deployed within the Company’s two distinct, but strategically aligned, business platforms: health benefits operating under UnitedHealthcare and health services operating under Optum.

Basis of Presentation, Uses of

Basis of Presentation, Uses of Estimates and Significant Accounting Policies (Notes)	12 Months Ended
	Dec. 31, 2016
Basis of Presentation and Significant Accounting Policies [Text Block]	Basis of Presentation, Use of Estimates and Significant Accounting Policies Basis of Presentation The Company has prepared the Consolidated Financial Statements according to U.S. Generally Accepted Accounting Principles (GAAP) and has included the accounts of UnitedHealth Group and its subsidiaries. Use of Estimates These Consolidated Financial Statements include certain amounts based on the Company’s best estimates and judgments. The Company’s most significant estimates relate to estimates and judgments for medical costs payable and revenues, valuation and impairment analysis of goodwill and other intangible assets, estimates of other current liabilities and other current receivables and valuations of certain investments. Certain of these estimates require the application of complex assumptions and judgments, often because they involve matters that are inherently uncertain and will likely change in subsequent periods. The impact of any change in estimates is included in earnings in the period in which the estimate is adjusted. Revenues Premiums Premium revenues are primarily derived from risk-based health insurance arrangements in which the premium is typically at a fixed rate per individual served for a one-year period, and the Company assumes the economic risk of funding its customers’ health care and related administrative costs. Premium revenues are recognized in the period in which eligible individuals are entitled to receive health care benefits. Health care premium payments received from the Company’s customers in advance of the service period are recorded as unearned revenues. Fully insured commercial products of U.S. health plans, Medicare Advantage and Medicare Prescription Drug Benefit (Medicare Part D) plans with medical loss ratios as calculated under the definitions in the Patient Protection and Affordable Care Act (ACA) and related federal and state regulations and implementing regulations, that fall below certain targets are required to rebate ratable portions of their premiums annually. Medicare Advantage premium revenue includes the impact of Centers for Medicare & Medicaid Services (CMS) quality bonuses based on plans’ Star ratings. Premium revenues are recognized based on the estimated premiums earned net of projected rebates because the Company is able to reasonably estimate the ultimate premiums of these contracts. The Company also records premium revenues from capitation arrangements at its OptumHealth businesses. The Company’s Medicare Advantage and Medicare Part D premium revenues are subject to periodic adjustment under CMS’ risk adjustment payment methodology. CMS deploys a risk adjustment model that apportions premiums paid to all health plans according to health severity and certain demographic factors. The CMS risk adjustment model provides higher per member payments for enrollees diagnosed with certain conditions and lower payments for enrollees who are healthier. Under this risk adjustment methodology, CMS calculates the risk adjusted premium payment using diagnosis data from hospital inpatient, hospital outpatient and physician treatment settings. The Company and health care providers collect, capture and submit the necessary and available diagnosis data to CMS within prescribed deadlines. The Company estimates risk adjustment revenues based upon the diagnosis data submitted and expected to be submitted to CMS. Risk adjustment data for certain of the Company’s plans are subject to review by the government, including audit by regulators. See Note 12 for additional information regarding these audits. Products and Services For the Company’s OptumRx pharmacy care services business, the majority of revenues are derived from products sold through a contracted network of retail pharmacies or home delivery and specialty pharmacy facilities. Product revenues include ingredient costs (net of rebates), a negotiated dispensing fee and customer co-payments for drugs dispensed through the Company’s mail-service pharmacy. In retail pharmacy transactions, revenues recognized exclude the member’s applicable co-payment. Pharmacy products are billed to customers based on the number of transactions occurring during the billing period. Product revenues are recognized when the prescriptions are dispensed through the retail network or received by consumers through the Company’s mail-service pharmacy. The Company has entered into contracts in which it is primarily obligated to pay its network pharmacy providers for benefits provided to their customers regardless of whether the Company is paid. The Company is also involved in establishing the prices charged by retail pharmacies, determining which drugs will be included in formulary listings and selecting which retail pharmacies will be included in the network offered to plan sponsors’ members. As a result, revenues are reported on a gross basis. Services revenue consists of fees derived from services performed for customers that self-insure the health care costs of their employees and employees’ dependents. Under service fee contracts, the Company receives monthly, a fixed fee per employee, which is recognized as revenue as the Company performs, or makes available the applicable services to the customer. The customers retain the risk of financing health care costs for their employees and employees’ dependents, and the Company administers the payment of customer funds to physicians and other health care professionals from customer-funded bank accounts. As the Company has neither the obligation for funding the health care costs, nor the primary responsibility for providing the medical care, the Company does not recognize premium revenue and medical costs for these contracts in its Consolidated Financial Statements. For these fee-based customer arrangements, the Company provides coordination and facilitation of medical services; transaction processing; customer, consumer and care professional services; and access to contracted networks of physicians, hospitals and other health care professionals. These services are performed throughout the contract period. Revenues are also comprised of a number of services and products sold through Optum. For its financial services offerings, OptumHealth charges fees and earns investment income on managed funds. OptumInsight provides software and information products, advisory consulting arrangements and services outsourcing contracts, which may be delivered over several years. OptumInsight revenues are generally recognized over time on either a time and materials basis, or ratably as services are performed or made available to customers. Medical Costs and Medical Costs Payable The Company’s estimate of medical costs payable represents management’s best estimate of its liability for unpaid medical costs as of December 31, 2016. Each period, the Company re-examines previously established medical costs payable estimates based on actual claim submissions and other changes in facts and circumstances. As more complete claim information becomes available, the Company adjusts the amount of the estimates and includes the changes in estimates in medical costs in the period in which the change is identified. Approximately 90% of claims related to medical care services are known and settled within 90 days from the date of service and substantially all within twelve months. Medical costs and medical costs payable include estimates of the Company’s obligations for medical care services that have been rendered on behalf of insured consumers, but for which claims have either not yet been received, processed, or paid. The Company develops estimates for medical care services incurred but not reported (IBNR), which includes estimates for claims that have not been received or fully processed, using an actuarial process that is consistently applied, centrally controlled and automated. The actuarial models consider factors such as time from date of service to claim processing, seasonal variances in medical care consumption, health care professional contract rate changes, medical care utilization and other medical cost trends, membership volume and demographics, the introduction of new technologies, benefit plan changes, and business mix changes related to products, customers and geography. In developing its medical costs payable estimates, the Company applies different estimation methods depending on which incurred claims are being estimated. For the most recent two months, the Company estimates claim costs incurred by applying observed medical cost trend factors to the average per member per month (PMPM) medical costs incurred in prior months for which more complete claim data are available, supplemented by a review of near-term completion factors (actuarial estimates, based upon historical experience and analysis of current trends, of the percentage of incurred claims during a given period that have been adjudicated by the Company at the date of estimation). For months prior to the most recent two months, the Company applies the completion factors to actual claims adjudicated-to-date to estimate the expected amount of ultimate incurred claims for those months. Cost of Products Sold The Company’s cost of products sold includes the cost of pharmaceuticals dispensed to unaffiliated customers either directly at its mail and specialty pharmacy locations, or indirectly through its nationwide network of participating pharmacies. Rebates attributable to non-affiliated clients are accrued as rebates receivable and a reduction of cost of products sold with a corresponding payable for the amounts of the rebates to be remitted to those non-affiliated clients in accordance with their contracts and recorded in the Consolidated Statements of Operations as a reduction of product revenue. Cost of products sold also includes the cost of personnel to support the Company’s transaction processing services, system sales, maintenance and professional services. Cash, Cash Equivalents and Investments Cash and cash equivalents are highly liquid investments that have an original maturity of three months or less. The fair value of cash and cash equivalents approximates their carrying value because of the short maturity of the instruments. Investments with maturities of less than one year are classified as short-term. Because of regulatory requirements, certain investments are included in long-term investments regardless of their maturity date. The Company classifies these investments as held-to-maturity and reports them at amortized cost. Substantially all other investments are classified as available-for-sale and reported at fair value based on quoted market prices, where available. The Company excludes unrealized gains and losses on investments in available-for-sale securities from net earnings and reports them as comprehensive income and, net of income tax effects, as a separate component of equity. To calculate realized gains and losses on the sale of investments, the Company specifically identifies the cost of each investment sold. The Company evaluates an investment for impairment by considering the length of time and extent to which market value has been less than cost or amortized cost, the financial condition and near-term prospects of the issuer as well as specific events or circumstances that may influence the operations of the issuer and the Company’s intent to sell the security or the likelihood that it will be required to sell the security before recovery of the entire amortized cost. New information and the passage of time can change these judgments. The Company manages its investment portfolio to limit its exposure to any one issuer or market sector, and largely limits its investments to investment grade quality. Securities downgraded below policy minimums after purchase will be disposed of in accordance with the Company’s investment policy. Assets Under Management The Company provides health insurance products and services to members of AARP under a Supplemental Health Insurance Program (the AARP Program) and to AARP members and non-members under separate Medicare Advantage and Medicare Part D arrangements. The products and services under the AARP Program include supplemental Medicare benefits, hospital indemnity insurance, including insurance for individuals between 50 to 64 years of age and other related products. Pursuant to the Company’s agreement, AARP Program assets are managed separately from the Company’s general investment portfolio and are used to pay costs associated with the AARP Program. These assets are invested at the Company’s discretion, within investment guidelines approved by AARP. The Company does not guarantee any rates of return on these investments and, upon any transfer of the AARP Program contract to another entity, the Company would transfer cash equal in amount to the fair value of these investments at the date of transfer to that entity. Because the purpose of these assets is to fund the medical costs payable, the rate stabilization fund (RSF) liabilities and other related liabilities associated with this AARP contract, assets under management are classified as current assets, consistent with the classification of these liabilities. The effects of changes in other balance sheet amounts associated with the AARP Program also accrue to the overall benefit of the AARP policyholders through the RSF balance. Accordingly, the Company excludes the effect of such changes in its Consolidated Statements of Cash Flows. Other Current Receivables Other current receivables include amounts due from pharmaceutical manufacturers for rebates and Medicare Part D drug discounts and other miscellaneous amounts due to the Company. The Company’s pharmacy care services businesses contract with pharmaceutical manufacturers, some of which provide rebates based on use of the manufacturers’ products by its affiliated and non-affiliated clients. The Company accrues rebates as they are earned by its clients on a monthly basis based on the terms of the applicable contracts, historical data and current estimates. The pharmacy care services businesses bill these rebates to the manufacturers on a monthly or quarterly basis depending on the contractual terms and records rebates attributable to affiliated clients as a reduction to medical costs. The Company generally receives rebates from two to five months after billing. As of December 31, 2016 and 2015, total pharmaceutical manufacturer rebates receivable included in other receivables in the Consolidated Balance Sheets amounted to $ 3.3 billion and $2.6 billion , respectively. For details on the Company’s Medicare Part D receivables see “Medicare Part D Pharmacy Benefits” below. Medicare Part D Pharmacy Benefits The Company serves as a plan sponsor offering Medicare Part D prescription drug insurance coverage under contracts with CMS. Under the Medicare Part D program, there are seven separate elements of payment received by the Company during the plan year. These payment elements are as follows: • CMS Premium. CMS pays a fixed monthly premium per member to the Company for the entire plan year. • Member Premium. Additionally, certain members pay a fixed monthly premium to the Company for the entire plan year. • Low-Income Premium Subsidy. For qualifying low-income members, CMS pays some or all of the member’s monthly premiums to the Company on the member’s behalf. • Catastrophic Reinsurance Subsidy . CMS pays the Company a cost reimbursement estimate monthly to fund the CMS obligation to pay approximately 80% of the costs incurred by individual members in excess of the individual annual out-of-pocket maximum. A settlement is made with CMS based on actual cost experience, after the end of the plan year. • Low-Income Member Cost Sharing Subsidy. For qualifying low-income members, CMS pays on the member’s behalf some or all of a member’s cost sharing amounts, such as deductibles and coinsurance. The cost sharing subsidy is funded by CMS through monthly payments to the Company. The Company administers and pays the subsidized portion of the claims on behalf of CMS, and a settlement payment is made between CMS and the Company based on actual claims and premium experience, after the end of the plan year. • CMS Risk-Share. Premiums from CMS are subject to risk corridor provisions that compare costs targeted in the Company’s annual bids by product and region to actual prescription drug costs, limited to actual costs that would have been incurred under the standard coverage as defined by CMS. Variances of more than 5% above or below the original bid submitted by the Company may result in CMS making additional payments to the Company or require the Company to refund to CMS a portion of the premiums it received. The Company estimates and recognizes an adjustment to premium revenues related to the risk corridor payment settlement based upon pharmacy claims experience to date. The estimate of the settlement associated with these risk corridor provisions requires the Company to consider factors that may not be certain, including estimates of eligible pharmacy costs and member eligibility status differences with CMS. The Company records risk-share adjustments to premium revenues in the Consolidated Statements of Operations and other current liabilities or other current receivables in the Consolidated Balance Sheets. • Drug Discount. The ACA mandated a consumer discount on brand name prescription drugs for Medicare Part D plan participants in the coverage gap. This discount is funded by CMS and pharmaceutical manufacturers while the Company administers the application of these funds. Accordingly, amounts received are not reflected as premium revenues, but rather are accounted for as deposits. The Company records a liability when amounts are received from CMS and a receivable when the Company bills the pharmaceutical manufacturers. Related cash flows are presented as customer funds administered within financing activities in the Consolidated Statements of Cash Flows. The CMS Premium, the Member Premium and the Low-Income Premium Subsidy represent payments for the Company’s insurance risk coverage under the Medicare Part D program and, therefore, are recorded as premium revenues in the Consolidated Statements of Operations. Premium revenues are recognized ratably over the period in which eligible individuals are entitled to receive prescription drug benefits. The Company records premium payments received in advance of the applicable service period in unearned revenues in the Consolidated Balance Sheets. The Catastrophic Reinsurance Subsidy and the Low-Income Member Cost Sharing Subsidy (Subsidies) represent cost reimbursements under the Medicare Part D program. Amounts received for these Subsidies are not reflected as premium revenues, but rather are accounted for as receivables and/or deposits. Related cash flows are presented as customer funds administered within financing activities in the Consolidated Statements of Cash Flows. Pharmacy care costs and administrative costs under the contract are expensed as incurred and are recognized in medical costs and operating costs, respectively, in the Consolidated Statements of Operations. The final 2016 risk-share amount is expected to be settled during the second half of 2017, and is subject to the reconciliation process with CMS. The Consolidated Balance Sheets include the following amounts associated with the Medicare Part D program: December 31, 2016 December 31, 2015 (in millions) Subsidies Drug Discount Risk-Share Subsidies Drug Discount Risk-Share Other current receivables $ 934 $ 543 $ — $ 1,703 $ 423 $ — Other current liabilities — 267 471 — 58 496 Property, Equipment and Capitalized Software Property, equipment and capitalized software are stated at cost, net of accumulated depreciation and amortization. Capitalized software consists of certain costs incurred in the development of internal-use software, including external direct costs of materials and services and applicable payroll costs of employees devoted to specific software development. The Company calculates depreciation and amortization using the straight-line method over the estimated useful lives of the assets. The useful lives for property, equipment and capitalized software are: Furniture, fixtures and equipment 3 to 7 years Buildings 35 to 40 years Capitalized software 3 to 5 years Leasehold improvements are depreciated over the shorter of the remaining lease term or their estimated useful economic life. Goodwill To determine whether goodwill is impaired, annually or more frequently if needed, the Company performs a multi-step impairment test. The Company may first assess qualitative factors to determine if it is more likely than not that the carrying value of a reporting unit exceeds its estimated fair value. The Company may also elect to skip the qualitative testing and proceed directly to the quantitative testing. When performing quantitative testing, the Company first estimates the fair values of its reporting units using discounted cash flows. To determine fair values, the Company must make assumptions about a wide variety of internal and external factors. Significant assumptions used in the impairment analysis include financial projections of free cash flow (including significant assumptions about operations, capital requirements and income taxes), long-term growth rates for determining terminal value and discount rates. Comparative market multiples are used to corroborate the results of the discounted cash flow test. If the fair value is less than the carrying value of the reporting unit, then the implied value of goodwill would be calculated and compared to the carrying amount of goodwill to determine whether goodwill is impaired. There was no impairment of goodwill during the year ended December 31, 2016 . Intangible Assets The Company’s intangible assets are subject to impairment tests when events or circumstances indicate that an intangible asset (or asset group) may be impaired. The Company’s indefinite lived intangible assets are also tested for impairment annually. There was no impairment of intangible assets during the year ended December 31, 2016 . Accounts Payable and Accrued Liabilities The Company had checks outstanding of $1.5 billion and $1.6 billion as of December 31, 2016 and 2015, respectively, which were classified as accounts payable and accrued liabilities and the change in this balance has been reflected within other financing activities in the Consolidated Statements of Cash Flows. Other Current Liabilities Other current liabilities include health savings account deposits ( $5.7 billion and $3.6 billion as of December 31, 2016 and 2015 , respectively), the RSF associated with the AARP Program, deposits under the Medicare Part D program (see “Medicare Part D Pharmacy Benefits” above), accruals for premium rebate payments under the ACA, the current portion of future policy benefits and customer balances. Future Policy Benefits Future policy benefits represent account balances that accrue to the benefit of the policyholders, excluding surrender charges, for universal life and investment annuity products and for long-duration health policies sold to individuals for which some of the premium received in the earlier years is intended to pay benefits to be incurred in future years. Policy Acquisition Costs The Company’s short duration health insurance contracts typically have a one-year term and may be canceled by the customer with at least 30 days’ notice. Costs related to the acquisition and renewal of short duration customer contracts are charged to expense as incurred. Redeemable Noncontrolling Interests Redeemable noncontrolling interests in the Company’s subsidiaries whose redemption is outside the control of the Company are classified as temporary equity. The following table provides details of the Company's redeemable noncontrolling interests’ activity for the years ended December 31, 2016 and 2015 : (in millions) 2016 2015 Redeemable noncontrolling interests, beginning of period $ 1,736 $ 1,388 Net earnings 16 29 Acquisitions 34 196 Redemptions (123 ) (116 ) Distributions (11 ) (19 ) Fair value and other adjustments 360 258 Redeemable noncontrolling interests, end of period $ 2,012 $ 1,736 Share-Based Compensation The Company recognizes compensation expense for share-based awards, including stock options, stock-settled stock appreciation rights (SARs) and restricted stock and restricted stock units (collectively, restricted shares), on a straight-line basis over the related service period (generally the vesting period) of the award, or to an employee’s eligible retirement date under the award agreement, if earlier. Restricted shares vest ratably; primarily over two to five years and compensation expense related to restricted shares is based on the share price on date of grant. Stock options and SARs vest ratably primarily over four years and may be exercised up to 10 years from the date of grant. Compensation expense related to stock options and SARs is based on the fair value at date of grant, which is estimated on the date of grant using a binomial option-pricing model. Under the Company’s Employee Stock Purchase Plan (ESPP) eligible employees are allowed to purchase the Company’s stock at a discounted price, which is 85% of the lower market price of the Company’s common stock at the beginning or at the end of the six-month purchase period. Share-based compensation expense for all programs is recognized in operating costs in the Consolidated Statements of Operations. Net Earnings Per Common Share The Company computes basic earnings per common share attributable to UnitedHealth Group common shareholders by dividing net earnings attributable to UnitedHealth Group common shareholders by the weighted-average number of common shares outstanding during the period. The Company determines diluted net earnings per common share attributable to UnitedHealth Group common shareholders using the weighted-average number of common shares outstanding during the period, adjusted for potentially dilutive shares associated with stock options, SARs, restricted shares and the ESPP, (collectively, common stock equivalents) using the treasury stock method. The treasury stock method assumes a hypothetical issuance of shares to settle the share-based awards, with the assumed proceeds used to purchase common stock at the average market price for the period. Assumed proceeds include the amount the employee must pay upon exercise and any unrecognized compensation cost. The difference between the number of shares assumed issued and number of shares assumed purchased represents the dilutive shares. Health Insurance Industry Tax The ACA includes an annual, nondeductible insurance industry tax (Health Insurance Industry Tax) to be levied proportionally across the insurance industry for risk-based health insurance products. The Company estimates its liability for the Health Insurance Industry Tax based on a ratio of the Company’s applicable net premiums written compared to the U.S. health insurance industry total applicable net premiums, both for the previous calendar year. The Company records in full the estimated liability for the Health Insurance Industry Tax at the beginning of the calendar year with a corresponding deferred cost that is amortized to operating costs on the Consolidated Statements of Operations using a straight-line method of allocation over the calendar year. The liability is recorded in accounts payable and accrued liabilities and the corresponding deferred cost is recorded in prepaid expenses and other current assets on the Consolidated Balance Sheets. A provision in the 2016 Federal Budget imposed a one year moratorium for 2017 on the collection of the Health Insurance Industry Tax. Premium Stabilization Programs The ACA included three programs designed to stabilize health insurance markets (Premium Stabilization Programs): a permanent risk adjustment program; a temporary risk corridors program; and a transitional reinsurance program (Reinsurance Program). The risk-adjustment provisions apply to market reform compliant individual and small group plans in the commercial markets. Under the program, each covered member is assigned a risk score based upon demographic information and applicable diagnostic codes from the current year paid claims, in order to determine an average risk score for each plan in a particular state and market risk pool. Generally, a plan with a risk score that is less than the state’s average risk score will pay into the pool, while a plan with a risk score that is greater than the state’s average will receive money from the pool. The temporary risk corridors provisions are intended to limit the gains and losses of individual and small group qualified health plans. Plans are required to calculate the U.S. Department of Health and Human Services (HHS) risk corridor ratio of allowable costs to the defined target amount. Qualified health plans with ratios below 97% are required to make payments to HHS, while plans with ratios greater than 103% expect to receive funds from HHS. The Reinsurance Program and temporary risk corridors program expired at the end of 2016. For the Premium Stabilization Programs, the Company records a receivable or payable as an adjustment to premium revenue based on year-to-date experience when the amounts are reasonably estimable and collection is reasonably assured. Final adjustments or recoverable amounts to the Premium Stabilization Programs are determined by HHS in the year following the policy year. Recently Issued Accounting Standards In February 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standard Update (ASU) No. 2016-02, “Leases (Topic 842)” (ASU 2016-02). Under ASU 2016-02, an entity will be required to recognize assets and liabilities for the rights and obligations created by leases on the entity’s balance sheet for both finance and operating leases. For leases with a term of 12 months or less, an entity can elect to not recognize lease assets and lease liabilities and expense the lease over a straight-line basis for the term of the lease. ASU 2016-02 will require new disclosures that depict the amount, timing, and uncertainty of cash flows pertaining to an entity’s leases. Companies are required to adopt the new standard using a modified retrospective approach for annual and interim periods beginning after December 15, 2018. Early adoption of ASU 2016-02 is permitted. When adopted, the Company does not expect ASU 2016-02 to have a material impact on its results of operations, equity or cash flows. The impact of ASU 2016-02 on the Company’s consolidated financial position will be based on leases outstanding at the time of adoption. In January 2016, the FASB issued ASU 2016-01, “Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities” (ASU 2016-01). The new guidance changes the current accounting related to (i) the classification and measurement of certain equity investments, (ii) the presentation of changes in the fair value of financial liabilities measured under the fair value option that are due to instrument-specific credit risk, and (iii) certain disclosures associated with the fair value of financial instruments. Most notably, ASU 2016-01 requires that equity investments, with certain exemptions, be measured at fair value with changes in fair value recognized in net income as opposed to other comprehensive income. The new guidance is effective for annual and interim reporting periods beginning after December 15, 2017. As of December 31, 2016, based on equity securities held, the Company does not expect ASU 2016-01 to have a material impact on its consolidated financial position, results of operations, equity or cash flows. The Company will continue to evaluate any changes in its mix of investments or market conditions and the related impact of ASU 2016-01. In May 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606)” (ASU 2014-09) as modified by ASU No. 2015-14, “Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date,” ASU 2016-08, “Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net),” ASU No. 2016-10, “Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing,” ASU No. 2016-12, “Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expe

Investments (Notes)

Investments (Notes)	12 Months Ended
	Dec. 31, 2016
Investments [Abstract]
Investments [Text Block]	Investments A summary of short-term and long-term investments by major security type is as follows: (in millions) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value December 31, 2016 Debt securities - available-for-sale: U.S. government and agency obligations $ 2,294 $ 1 $ (31 ) $ 2,264 State and municipal obligations 7,120 40 (101 ) 7,059 Corporate obligations 10,944 41 (58 ) 10,927 U.S. agency mortgage-backed securities 2,963 7 (43 ) 2,927 Non-U.S. agency mortgage-backed securities 1,009 3 (10 ) 1,002 Total debt securities - available-for-sale 24,330 92 (243 ) 24,179 Equity securities 2,036 52 (47 ) 2,041 Debt securities - held-to-maturity: U.S. government and agency obligations 250 1 — 251 State and municipal obligations 5 — — 5 Corporate obligations 238 — — 238 Total debt securities - held-to-maturity 493 1 — 494 Total investments $ 26,859 $ 145 $ (290 ) $ 26,714 December 31, 2015 Debt securities - available-for-sale: U.S. government and agency obligations $ 1,982 $ 1 $ (6 ) $ 1,977 State and municipal obligations 6,022 149 (3 ) 6,168 Corporate obligations 7,446 41 (81 ) 7,406 U.S. agency mortgage-backed securities 2,127 13 (16 ) 2,124 Non-U.S. agency mortgage-backed securities 962 5 (11 ) 956 Total debt securities - available-for-sale 18,539 209 (117 ) 18,631 Equity securities 1,638 58 (57 ) 1,639 Debt securities - held-to-maturity: U.S. government and agency obligations 163 1 — 164 State and municipal obligations 8 — — 8 Corporate obligations 339 — — 339 Total debt securities - held-to-maturity 510 1 — 511 Total investments $ 20,687 $ 268 $ (174 ) $ 20,781 Nearly all of the Company’s investments in mortgage-backed securities were rated AAA as of December 31, 2016 . The amortized cost and fair value of debt securities as of December 31, 2016 , by contractual maturity, were as follows: Available-for-Sale Held-to-Maturity (in millions) Amortized Cost Fair Value Amortized Fair Due in one year or less $ 2,893 $ 2,895 $ 151 $ 151 Due after one year through five years 9,646 9,625 153 153 Due after five years through ten years 5,706 5,645 124 124 Due after ten years 2,113 2,085 65 66 U.S. agency mortgage-backed securities 2,963 2,927 — — Non-U.S. agency mortgage-backed securities 1,009 1,002 — — Total debt securities $ 24,330 $ 24,179 $ 493 $ 494 The fair value of available-for-sale investments with gross unrealized losses by major security type and length of time that individual securities have been in a continuous unrealized loss position were as follows: Less Than 12 Months 12 Months or Greater Total (in millions) Fair Value Gross Unrealized Losses Fair Value Gross Fair Value Gross December 31, 2016 Debt securities - available-for-sale: U.S. government and agency obligations $ 1,794 $ (31 ) $ — $ — $ 1,794 $ (31 ) State and municipal obligations 4,376 (101 ) — — 4,376 (101 ) Corporate obligations 5,128 (56 ) 137 (2 ) 5,265 (58 ) U.S. agency mortgage-backed securities 2,247 (40 ) 79 (3 ) 2,326 (43 ) Non-U.S. agency mortgage-backed securities 544 (7 ) 97 (3 ) 641 (10 ) Total debt securities - available-for-sale $ 14,089 $ (235 ) $ 313 $ (8 ) $ 14,402 $ (243 ) Equity securities $ 93 $ (5 ) $ 91 $ (42 ) $ 184 $ (47 ) December 31, 2015 Debt securities - available-for-sale: U.S. government and agency obligations $ 1,473 $ (6 ) $ — $ — $ 1,473 $ (6 ) State and municipal obligations 650 (3 ) — — 650 (3 ) Corporate obligations 4,629 (63 ) 339 (18 ) 4,968 (81 ) U.S. agency mortgage-backed securities 1,304 (12 ) 116 (4 ) 1,420 (16 ) Non-U.S. agency mortgage-backed securities 593 (7 ) 127 (4 ) 720 (11 ) Total debt securities - available-for-sale $ 8,649 $ (91 ) $ 582 $ (26 ) $ 9,231 $ (117 ) Equity securities $ 112 $ (11 ) $ 89 $ (46 ) $ 201 $ (57 ) The Company’s unrealized losses from all securities as of December 31, 2016 were generated from approximately 12,000 positions out of a total of 27,000 positions. The Company believes that it will collect the principal and interest due on its debt securities that have an amortized cost in excess of fair value. The unrealized losses were primarily caused by interest rate increases and not by unfavorable changes in the credit quality associated with these securities. At each reporting period, the Company evaluates securities for impairment when the fair value of the investment is less than its amortized cost. The Company evaluated the underlying credit quality and credit ratings of the issuers, noting no significant deterioration since purchase. As of December 31, 2016 , the Company did not have the intent to sell any of the securities in an unrealized loss position. Therefore, the Company believes these losses to be temporary. The Company’s investments in equity securities consist of investments in Brazilian real denominated fixed-income funds, employee savings plan related investments, venture capital funds and dividend paying stocks. The Company evaluated its investments in equity securities for severity and duration of unrealized loss, overall market volatility and other market factors. Net realized gains reclassified out of accumulated other comprehensive income were from the following sources: For the Years Ended December 31, (in millions) 2016 2015 2014 Total other-than-temporary impairment recognized in earnings $ (45 ) $ (22 ) $ (26 ) Gross realized losses from sales (44 ) (28 ) (47 ) Gross realized gains from sales 255 191 284 Net realized gains (included in investment and other income on the Consolidated Statements of Operations) 166 141 211 Income tax effect (included in provision for income taxes on the Consolidated Statements of Operations) (60 ) (53 ) (77 ) Realized gains, net of taxes $ 106 $ 88 $ 134

Fair Value (Notes)

Fair Value (Notes)	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value [Text Block]	Fair Value Certain assets and liabilities are measured at fair value in the Consolidated Financial Statements or have fair values disclosed in the Notes to the Consolidated Financial Statements. These assets and liabilities are classified into one of three levels of a hierarchy defined by GAAP. In instances in which the inputs used to measure fair value fall into different levels of the fair value hierarchy, the fair value measurement is categorized in its entirety based on the lowest level input that is significant to the fair value measurement in its entirety. The Company’s assessment of the significance of a particular item to the fair value measurement in its entirety requires judgment, including the consideration of inputs specific to the asset or liability. The fair value hierarchy is summarized as follows: Level 1 — Quoted prices (unadjusted) for identical assets/liabilities in active markets. Level 2 — Other observable inputs, either directly or indirectly, including: • Quoted prices for similar assets/liabilities in active markets; • Quoted prices for identical or similar assets/liabilities in inactive markets (e.g., few transactions, limited information, noncurrent prices, high variability over time); • Inputs other than quoted prices that are observable for the asset/liability (e.g., interest rates, yield curves, implied volatilities, credit spreads); and • Inputs that are corroborated by other observable market data. Level 3 — Unobservable inputs that cannot be corroborated by observable market data. Transfers between levels, if any, are recorded as of the beginning of the reporting period in which the transfer occurs; there was no transfer between Levels 1, 2 or 3 of any financial assets or liabilities during the years ended December 31, 2016 or 2015 . Nonfinancial assets and liabilities or financial assets and liabilities that are measured at fair value on a nonrecurring basis are subject to fair value adjustments only in certain circumstances, such as when the Company records an impairment. There were no significant fair value adjustments for these assets and liabilities recorded during the years ended December 31, 2016 or 2015 . The following methods and assumptions were used to estimate the fair value and determine the fair value hierarchy classification of each class of financial instrument included in the tables below: Cash and Cash Equivalents. The carrying value of cash and cash equivalents approximates fair value as maturities are less than three months. Fair values of cash equivalent instruments that do not trade on a regular basis in active markets are classified as Level 2. Debt and Equity Securities. Fair values of debt and equity securities are based on quoted market prices, where available. The Company obtains one price for each security primarily from a third-party pricing service (pricing service), which generally uses quoted or other observable inputs for the determination of fair value. The pricing service normally derives the security prices through recently reported trades for identical or similar securities, and, if necessary, makes adjustments through the reporting date based upon available observable market information. For securities not actively traded, the pricing service may use quoted market prices of comparable instruments or discounted cash flow analyses, incorporating inputs that are currently observable in the markets for similar securities. Inputs that are often used in the valuation methodologies include, but are not limited to, benchmark yields, credit spreads, default rates, prepayment speeds and nonbinding broker quotes. As the Company is responsible for the determination of fair value, it performs quarterly analyses on the prices received from the pricing service to determine whether the prices are reasonable estimates of fair value. Specifically, the Company compares the prices received from the pricing service to prices reported by a secondary pricing source, such as its custodian, its investment consultant and third-party investment advisors. Additionally, the Company compares changes in the reported market values and returns to relevant market indices to test the reasonableness of the reported prices. The Company’s internal price verification procedures and reviews of fair value methodology documentation provided by independent pricing services have not historically resulted in adjustment in the prices obtained from the pricing service. Fair values of debt securities that do not trade on a regular basis in active markets but are priced using other observable inputs are classified as Level 2. Fair value estimates for Level 1 and Level 2 equity securities are based on quoted market prices for actively traded equity securities and/or other market data for the same or comparable instruments and transactions in establishing the prices. The fair values of Level 3 investments in venture capital portfolios are estimated using a market valuation technique that relies heavily on management assumptions and qualitative observations. Under the market approach, the fair values of the Company’s various venture capital investments are computed using limited quantitative and qualitative observations of activity for similar companies in the current market. The Company’s market modeling utilizes, as applicable, transactions for comparable companies in similar industries that also have similar revenue and growth characteristics and preferences in their capital structure. Key significant unobservable inputs in the market technique include implied earnings before interest, taxes, depreciation and amortization (EBITDA) multiples and revenue multiples. Additionally, the fair values of certain of the Company’s venture capital securities are based on recent transactions in inactive markets for identical or similar securities. Significant changes in any of these inputs could result in significantly lower or higher fair value measurements. Throughout the procedures discussed above in relation to the Company’s processes for validating third-party pricing information, the Company validates the understanding of assumptions and inputs used in security pricing and determines the proper classification in the hierarchy based on that understanding. Assets Under Management. Assets under management consists of debt securities and other investments held to fund costs associated with the AARP Program and are priced and classified using the same methodologies as the Company’s investments in debt and equity securities. Other Assets. The fair values of the Company’s other assets are estimated and classified using the same methodologies as the Company’s investments in debt securities. Interest Rate Swaps. Fair values of the Company’s swaps are estimated using the terms of the swaps and publicly available information, including market yield curves. Because the swaps are unique and not actively traded but are valued using other observable inputs, the fair values are classified as Level 2. Long-Term Debt. The fair values of the Company’s long-term debt are estimated and classified using the same methodologies as the Company’s investments in debt securities. The following table presents a summary of fair value measurements by level and carrying values for items measured at fair value on a recurring basis in the Consolidated Balance Sheets: (in millions) Quoted Prices in Active Markets (Level 1) Other Observable Inputs (Level 2) Unobservable Inputs (Level 3) Total Fair and Carrying Value December 31, 2016 Cash and cash equivalents $ 10,386 $ 44 $ — $ 10,430 Debt securities - available-for-sale: U.S. government and agency obligations 2,017 247 — 2,264 State and municipal obligations — 7,059 — 7,059 Corporate obligations 21 10,804 102 10,927 U.S. agency mortgage-backed securities — 2,927 — 2,927 Non-U.S. agency mortgage-backed securities — 1,002 — 1,002 Total debt securities - available-for-sale 2,038 22,039 102 24,179 Equity securities 1,591 13 437 2,041 Assets under management 1,064 2,041 — 3,105 Interest rate swap assets — 55 — 55 Total assets at fair value $ 15,079 $ 24,192 $ 539 $ 39,810 Percentage of total assets at fair value 38 % 61 % 1 % 100 % Interest rate swap liabilities $ — $ 14 $ — $ 14 December 31, 2015 Cash and cash equivalents $ 10,906 $ 17 $ — $ 10,923 Debt securities - available-for-sale: U.S. government and agency obligations 1,779 198 — 1,977 State and municipal obligations — 6,168 — 6,168 Corporate obligations 5 7,308 93 7,406 U.S. agency mortgage-backed securities — 2,124 — 2,124 Non-U.S. agency mortgage-backed securities — 951 5 956 Total debt securities - available-for-sale 1,784 16,749 98 18,631 Equity securities 1,223 14 402 1,639 Assets under management 832 2,166 — 2,998 Interest rate swap assets — 93 — 93 Total assets at fair value $ 14,745 $ 19,039 $ 500 $ 34,284 Percentage of total assets at fair value 43 % 56 % 1 % 100 % Interest rate swap liabilities $ — $ 11 $ — $ 11 The following table presents a summary of fair value measurements by level and carrying values for certain financial instruments not measured at fair value on a recurring basis in the Consolidated Balance Sheets: (in millions) Quoted Prices in Active Markets (Level 1) Other Observable Inputs (Level 2) Unobservable Inputs (Level 3) Total Fair Value Total Carrying Value December 31, 2016 Debt securities - held-to-maturity: U.S. government and agency obligations $ 251 $ — $ — $ 251 $ 250 State and municipal obligations — — 5 5 5 Corporate obligations 20 8 210 238 238 Total debt securities - held-to-maturity $ 271 $ 8 $ 215 $ 494 $ 493 Other assets $ — $ 476 $ — $ 476 $ 471 Long-term debt and other financing obligations $ — $ 31,295 $ — $ 31,295 $ 29,337 December 31, 2015 Debt securities - held-to-maturity: U.S. government and agency obligations $ 164 $ — $ — $ 164 $ 163 State and municipal obligations — — 8 8 8 Corporate obligations 91 10 238 339 339 Total debt securities - held-to-maturity $ 255 $ 10 $ 246 $ 511 $ 510 Other assets $ — $ 493 $ — $ 493 $ 500 Long-term debt and other financing obligations $ — $ 29,455 $ — $ 29,455 $ 27,978 The carrying amounts reported on the Consolidated Balance Sheets for other current financial assets and liabilities approximate fair value because of their short-term nature. These assets and liabilities are not listed in the table above. A reconciliation of the beginning and ending balances of assets measured at fair value on a recurring basis using Level 3 inputs is as follows: December 31, 2016 December 31, 2015 December 31, 2014 (in millions) Debt Securities Equity Securities Total Debt Securities Equity Securities Total Debt Securities Equity Securities Total Balance at beginning of period $ 98 $ 402 $ 500 $ 74 $ 310 $ 384 $ 42 $ 269 $ 311 Purchases 12 100 112 27 106 133 32 105 137 Sales (9 ) (29 ) (38 ) (4 ) (24 ) (28 ) (1 ) (180 ) (181 ) Net unrealized gains (losses) in accumulated other comprehensive income 1 (13 ) (12 ) 2 5 7 1 6 7 Net realized (losses) gains in investment and other income — (23 ) (23 ) (1 ) 5 4 — 110 110 Balance at end of period $ 102 $ 437 $ 539 $ 98 $ 402 $ 500 $ 74 $ 310 $ 384 The following table presents quantitative information regarding unobservable inputs that were significant to the valuation of assets measured at fair value on a recurring basis using Level 3 inputs: Range (in millions) Fair Value Valuation Technique Unobservable Input Low High December 31, 2016 Equity securities: Venture capital portfolios $ 404 Market approach - comparable companies Revenue multiple 1.0 6.0 EBITDA multiple 8.0 12.0 33 Market approach - recent transactions Inactive market transactions N/A N/A Total equity securities $ 437 Also included in the Company’s assets measured at fair value on a recurring basis using Level 3 inputs were $102 million of available-for-sale debt securities as of December 31, 2016 , which were not significant.

Property, Plant, and Capitalize

Property, Plant, and Capitalized Software (Notes)	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment Disclosure [Text Block]	Property, Equipment and Capitalized Software A summary of property, equipment and capitalized software is as follows: (in millions) December 31, 2016 December 31, 2015 Land and improvements $ 324 $ 237 Buildings and improvements 3,148 2,420 Computer equipment 2,021 1,945 Furniture and fixtures 999 790 Less accumulated depreciation (2,621 ) (2,163 ) Property and equipment, net 3,871 3,229 Capitalized software 3,158 2,642 Less accumulated amortization (1,128 ) (1,010 ) Capitalized software, net 2,030 1,632 Total property, equipment and capitalized software, net $ 5,901 $ 4,861 Depreciation expense for property and equipment for the years ended December 31, 2016 , 2015 and 2014 was $698 million , $613 million and $532 million , respectively. Amortization expense for capitalized software for the years ended December 31, 2016 , 2015 and 2014 was $475 million , $430 million and $422 million , respectively.

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Notes)	12 Months Ended
	Dec. 31, 2016
Goodwill [Line Items]
Goodwill Disclosure [Text Block]	Goodwill and Other Intangible Assets Changes in the carrying amount of goodwill, by reportable segment, were as follows: (in millions) UnitedHealthcare OptumHealth OptumInsight OptumRx Consolidated Balance at January 1, 2015 $ 24,030 $ 3,834 $ 4,236 $ 840 $ 32,940 Acquisitions 128 1,817 89 10,732 12,766 Foreign currency effects and adjustments, net (1,233 ) 9 (29 ) — (1,253 ) Balance at December 31, 2015 22,925 5,660 4,296 11,572 44,453 Acquisitions 526 683 — 1,387 2,596 Foreign currency effects and adjustments, net 403 (21 ) 153 — 535 Balance at December 31, 2016 $ 23,854 $ 6,322 $ 4,449 $ 12,959 $ 47,584 During the third quarter of 2015, the Company acquired all of the outstanding common shares of Catamaran Corporation and funded Catamaran’s payoff of its outstanding debt and credit facility for a total of $14.3 billion in cash. This combination diversified OptumRx’s customer and business mix and enhanced OptumRx’s technology capabilities and flexible service offerings. The total consideration exceeded the estimated fair value of the net tangible assets acquired by $16.0 billion , of which $5.4 billion has been allocated to finite-lived intangible assets and $10.6 billion to goodwill. The goodwill is not deductible for income tax purposes. The gross carrying value, accumulated amortization and net carrying value of other intangible assets were as follows: December 31, 2016 December 31, 2015 (in millions) Gross Carrying Value Accumulated Amortization Net Carrying Value Gross Carrying Value Accumulated Amortization Net Carrying Value Customer-related $ 10,942 $ (3,416 ) $ 7,526 $ 10,270 $ (2,796 ) $ 7,474 Trademarks and technology 720 (323 ) 397 682 (249 ) 433 Trademarks - indefinite-lived 468 — 468 358 — 358 Other 258 (108 ) 150 209 (83 ) 126 Total $ 12,388 $ (3,847 ) $ 8,541 $ 11,519 $ (3,128 ) $ 8,391 The acquisition date fair values and weighted-average useful lives assigned to finite-lived intangible assets acquired in business combinations consisted of the following by year of acquisition: 2016 2015 (in millions, except years) Fair Value Weighted-Average Useful Life Fair Value Weighted-Average Useful Life Customer-related $ 785 17 years $ 5,518 19 years Trademarks and technology 82 4 years 194 4 years Other 22 5 years — Total acquired finite-lived intangible assets $ 889 16 years $ 5,712 19 years Estimated full year amortization expense relating to intangible assets for each of the next five years ending December 31 is as follows: (in millions) 2017 $ 865 2018 755 2019 679 2020 596 2021 536 Amortization expense relating to intangible assets for the years ended December 31, 2016 , 2015 and 2014 was $882 million , $650 million and $524 million , respectively.

Medical Costs Payable (Notes)

Medical Costs Payable (Notes)	12 Months Ended
	Dec. 31, 2016
Medical Costs Payable	Medical Costs Payable The following table shows the components of the change in medical costs payable for the years ended December 31: (in millions) 2016 2015 2014 Medical costs payable, beginning of period $ 14,330 $ 12,040 $ 11,575 Reported medical costs: Current year 117,258 104,195 94,053 Prior years (220 ) (320 ) (420 ) Total reported medical costs 117,038 103,875 93,633 Medical payments: Payments for current year (101,696 ) (90,630 ) (82,750 ) Payments for prior years (13,281 ) (10,955 ) (10,418 ) Total medical payments (114,977 ) (101,585 ) (93,168 ) Medical costs payable, end of period $ 16,391 $ 14,330 $ 12,040 For the years ended December 31, 2016 , 2015 and 2014 the medical cost reserve development included no individual factors that were material . Medical costs payable included IBNR of $11.6 billion and $9.8 billion at December 31, 2016 and 2015, respectively. Substantially all of the IBNR balance as of December 31, 2016 relates to the current year. The following is information about incurred and paid medical cost development as of December 31, 2016 : Net Incurred Medical Costs (in millions) For the Years ended December 31, Year 2015 2016 2015 $ 104,195 $ 103,973 2016 117,258 Total $ 221,231 Net Cumulative Medical Payments (in millions) For the Years ended December 31, Year 2015 2016 2015 $ (90,630 ) $ (103,885 ) 2016 (101,696 ) Total (205,581 ) Net remaining outstanding liabilities prior to 2015 741 Total medical costs payable $ 16,391

Commercial Paper and Long-Term

Commercial Paper and Long-Term Debt (Notes)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Commercial Paper and Long-Term Debt [Text Block]	Commercial Paper and Long-Term Debt Commercial paper, term loan and senior unsecured long-term debt consisted of the following: December 31, 2016 December 31, 2015 (in millions, except percentages) Par Value Carrying Value Fair Value Par Value Carrying Value (a) Fair Value Commercial paper $ 3,633 $ 3,633 $ 3,633 $ 3,987 $ 3,987 $ 3,987 Floating rate term loan due July 2016 — — — 1,500 1,500 1,500 5.375% notes due March 2016 — — — 601 605 606 1.875% notes due November 2016 — — — 400 400 403 5.360% notes due November 2016 — — — 95 95 98 Floating rate notes due January 2017 750 750 750 750 749 751 6.000% notes due June 2017 441 446 450 441 458 469 1.450% notes due July 2017 750 750 751 750 749 750 1.400% notes due October 2017 625 624 626 625 624 624 6.000% notes due November 2017 156 159 163 156 162 168 1.400% notes due December 2017 750 751 750 750 751 748 6.000% notes due February 2018 1,100 1,107 1,153 1,100 1,114 1,196 1.900% notes due July 2018 1,500 1,496 1,507 1,500 1,494 1,505 1.700% notes due February 2019 750 748 748 — — — 1.625% notes due March 2019 500 501 498 500 502 494 2.300% notes due December 2019 500 498 504 500 499 502 2.700% notes due July 2020 1,500 1,495 1,523 1,500 1,493 1,516 3.875% notes due October 2020 450 450 474 450 452 476 4.700% notes due February 2021 400 409 433 400 413 438 2.125% notes due March 2021 750 745 741 — — — 3.375% notes due November 2021 500 497 519 500 500 517 2.875% notes due December 2021 750 748 760 750 753 760 2.875% notes due March 2022 1,100 1,057 1,114 1,100 1,059 1,099 3.350% notes due July 2022 1,000 995 1,030 1,000 994 1,023 0.000% notes due November 2022 15 11 12 15 10 11 2.750% notes due February 2023 625 609 622 625 611 613 2.875% notes due March 2023 750 771 753 750 781 742 3.750% notes due July 2025 2,000 1,986 2,070 2,000 1,985 2,062 3.100% notes due March 2026 1,000 994 986 — — — 3.450% notes due January 2027 750 745 762 — — — 4.625% notes due July 2035 1,000 991 1,090 1,000 991 1,038 5.800% notes due March 2036 850 837 1,034 850 838 1,003 6.500% notes due June 2037 500 491 643 500 492 628 6.625% notes due November 2037 650 640 850 650 641 829 6.875% notes due February 2038 1,100 1,075 1,497 1,100 1,076 1,439 5.700% notes due October 2040 300 296 366 300 296 348 5.950% notes due February 2041 350 345 437 350 345 416 4.625% notes due November 2041 600 588 634 600 588 609 4.375% notes due March 2042 502 483 509 502 483 493 3.950% notes due October 2042 625 606 609 625 606 582 4.250% notes due March 2043 750 734 765 750 734 728 4.750% notes due July 2045 2,000 1,972 2,203 2,000 1,971 2,107 4.200% notes due January 2047 750 737 759 — — — Total commercial paper, term loan and long-term debt $ 33,022 $ 32,770 $ 34,728 $ 31,972 $ 31,801 $ 33,278 (a) In the first quarter of 2016, the Company adopted ASU 2015-03, retrospectively as required. See Note 2 for more information on the adoption of ASU 2015-03. The Company’s long-term debt obligations also included $200 million and $164 million of other financing obligations, of which $80 million and $47 million were current as of December 31, 2016 and 2015, respectively. Maturities of commercial paper and long-term debt for the years ending December 31 are as follows: (in millions) 2017 $ 7,185 2018 2,622 2019 1,769 2020 1,955 2021 2,407 Thereafter 17,284 Commercial Paper and Revolving Bank Credit Facilities Commercial paper consists of short-duration, senior unsecured debt privately placed on a discount basis through broker-dealers. As of December 31, 2016 , the Company’s outstanding commercial paper had a weighted-average annual interest rate of 0.9% . The Company has $3.0 billion five-year, $2.0 billion three-year and $1.0 billion 364-day revolving bank credit facilities with 23 banks, which mature in December 2021 , December 2019 , and December 2017 , respectively. These facilities provide liquidity support for the Company’s commercial paper program and are available for general corporate purposes. As of December 31, 2016 , no amounts had been drawn on any of the bank credit facilities. The annual interest rates, which are variable based on term, are calculated based on the London Interbank Offered Rate (LIBOR) plus a credit spread based on the Company’s senior unsecured credit ratings. If amounts had been drawn on the bank credit facilities as of December 31, 2016 , annual interest rates would have ranged from 1.6% to 2.2% . Debt Covenants The Company’s bank credit facilities contain various covenants, including requiring the Company to maintain a debt to debt-plus-shareholders’ equity ratio of not more than 55% . The Company was in compliance with its debt covenants as of December 31, 2016 .

Income Taxes (Notes)

Income Taxes (Notes)	12 Months Ended
	Dec. 31, 2016
Income Tax Examination [Line Items]
Income Tax Disclosure [Text Block]	Income Taxes The current income tax provision reflects the tax consequences of revenues and expenses currently taxable or deductible on various income tax returns for the year reported. The deferred income tax provision or benefit generally reflects the net change in deferred income tax assets and liabilities during the year, excluding any deferred income tax assets and liabilities of acquired businesses. The components of the provision for income taxes for the years ended December 31 are as follows: (in millions) 2016 2015 2014 Current Provision: Federal $ 4,397 $ 4,155 $ 3,883 State and local 312 281 271 Total current provision 4,709 4,436 4,154 Deferred provision (benefit) 81 (73 ) (117 ) Total provision for income taxes $ 4,790 $ 4,363 $ 4,037 The reconciliation of the tax provision at the U.S. federal statutory rate to the provision for income taxes and the effective tax rate for the years ended December 31 is as follows: (in millions, except percentages) 2016 2015 2014 Tax provision at the U.S. federal statutory rate $ 4,152 35.0 % $ 3,581 35.0 % $ 3,380 35.0 % Health insurance industry tax 645 5.4 627 6.1 469 4.8 State income taxes, net of federal benefit 205 1.7 145 1.4 154 1.6 Share-based awards - excess tax benefit (158 ) (1.3 ) — — — — Non-deductible compensation 128 1.1 103 1.0 96 1.0 Other, net (182 ) (1.5 ) (93 ) (0.9 ) (62 ) (0.6 ) Provision for income taxes $ 4,790 40.4 % $ 4,363 42.6 % $ 4,037 41.8 % Deferred income tax assets and liabilities are recognized for the differences between the financial and income tax reporting bases of assets and liabilities based on enacted tax rates and laws. The components of deferred income tax assets and liabilities as of December 31 are as follows: (in millions) 2016 2015 Deferred income tax assets: Accrued expenses and allowances $ 820 $ 739 U.S. federal and state net operating loss carryforwards 147 139 Share-based compensation 126 124 Nondeductible liabilities 236 205 Medical costs payable and other current liabilities 95 71 Non-U.S. tax loss carryforwards 434 244 Net unrealized losses on investments 55 — Other-domestic 194 214 Other-non-U.S. 175 130 Subtotal 2,282 1,866 Less: valuation allowances (55 ) (44 ) Total deferred income tax assets 2,227 1,822 Deferred income tax liabilities: U.S. federal and state intangible assets (3,055 ) (2,951 ) Non-U.S. goodwill and intangible assets (584 ) (397 ) Capitalized software (707 ) (574 ) Net unrealized gains on investments — (34 ) Depreciation and amortization (332 ) (312 ) Prepaid expenses (228 ) (205 ) Other-non-U.S. (82 ) (76 ) Total deferred income tax liabilities (4,988 ) (4,549 ) Net deferred income tax liabilities $ (2,761 ) $ (2,727 ) Valuation allowances are provided when it is considered more likely than not that deferred tax assets will not be realized. The valuation allowances primarily relate to future tax benefits on certain federal, state and non-U.S. net operating loss carryforwards. Federal net operating loss carryforwards of $74 million expire beginning in 2021 through 2036; state net operating loss carryforwards expire beginning in 2017 through 2036. Substantially all of the non-U.S. tax loss carryforwards have indefinite carryforward periods. As of December 31, 2016 , the Company had $717 million of undistributed earnings from non-U.S. subsidiaries that are intended to be reinvested in non-U.S. operations. Because these earnings are considered permanently reinvested, no U.S. tax provision has been accrued related to the repatriation of these earnings. It is not practicable to estimate the amount of U.S. tax that might be payable on the eventual remittance of such earnings. A reconciliation of the beginning and ending amount of unrecognized tax benefits as of December 31 is as follows: (in millions) 2016 2015 2014 Gross unrecognized tax benefits, beginning of period $ 224 $ 92 $ 89 Gross increases: Current year tax positions 37 — — Prior year tax positions 24 55 4 Acquired reserves — 89 — Gross decreases: Prior year tax positions (4 ) (2 ) — Settlements (6 ) (1 ) — Statute of limitations lapses (12 ) (9 ) (1 ) Gross unrecognized tax benefits, end of period $ 263 $ 224 $ 92 The Company believes it is reasonably possible that its liability for unrecognized tax benefits will decrease in the next twelve months by $197 million as a result of audit settlements and the expiration of statutes of limitations. The Company classifies interest and penalties associated with uncertain income tax positions as income taxes within its Consolidated Statement of Operations. During the years ended December 31, 2016 , 2015 and 2014 the Company recognized $11 million , $11 million and $6 million of interest and penalties, respectively. The Company had $70 million and $59 million of accrued interest and penalties for uncertain tax positions as of December 31, 2016 and 2015, respectively. These amounts are not included in the reconciliation above. The Company currently files income tax returns in the United States, various states and non-U.S. jurisdictions. The U.S. Internal Revenue Service (IRS) has completed exams on the consolidated income tax returns for fiscal years 2015 and prior. The Company’s 2016 tax year is under advance review by the IRS under its Compliance Assurance Program. With the exception of a few states, the Company is no longer subject to income tax examinations prior to the 2010 tax year. The Brazilian federal revenue service - Secretaria da Receita Federal (SRF) may audit the Company’s Brazilian subsidiaries for a period of five years from the date on which corporate income taxes should have been paid and/or the date when the tax return was filed.

Shareholders' Equity (Notes)

Shareholders' Equity (Notes)	12 Months Ended
	Dec. 31, 2016
Shareholders' Equity [Abstract]
Stockholders' Equity Note Disclosure [Text Block]	Shareholders' Equity Regulatory Capital and Dividend Restrictions The Company’s regulated subsidiaries are subject to regulations and standards in their respective jurisdictions. These standards, among other things, require these subsidiaries to maintain specified levels of statutory capital, as defined by each jurisdiction, and restrict the timing and amount of dividends and other distributions that may be paid to their parent companies. In the United States, most of these regulations and standards are generally consistent with model regulations established by the National Association of Insurance Commissioners. These standards generally permit dividends to be paid from statutory unassigned surplus of the regulated subsidiary and are limited based on the regulated subsidiary’s level of statutory net income and statutory capital and surplus. These dividends are referred to as “ordinary dividends” and generally can be paid without prior regulatory approval. If the dividend, together with other dividends paid within the preceding twelve months, exceeds a specified statutory limit or is paid from sources other than earned surplus, it is generally considered an “extraordinary dividend” and must receive prior regulatory approval. For the year ended December 31, 2016 , the Company’s regulated subsidiaries paid their parent companies dividends of $3.9 billion , including $3.3 billion of extraordinary dividends. For the year ended December 31, 2015 , the Company’s regulated subsidiaries paid their parent companies dividends of $4.4 billion , including $1.5 billion of extraordinary dividends. As of December 31, 2016 , approximately $700 million of the Company’s $10.4 billion of cash and cash equivalents was available for general corporate use. The Company's regulated subsidiaries had estimated aggregate statutory capital and surplus of approximately $17.9 billion as of December 31, 2016 . The estimated statutory capital and surplus necessary to satisfy regulatory requirements of the Company's regulated subsidiaries was approximately $10.5 billion as of December 31, 2016 . Optum Bank must meet minimum requirements for Tier 1 leverage capital, Tier 1 risk-based capital, common equity Tier1 risk-based capital and total risk-based capital of the Federal Deposit Insurance Corporation (FDIC) to be considered “Well Capitalized” under the capital adequacy rules to which it is subject. At December 31, 2016 , the Company believes that Optum Bank met the FDIC requirements to be considered “Well Capitalized.” Share Repurchase Program Under its Board of Directors’ authorization, the Company maintains a share repurchase program. The objectives of the share repurchase program are to optimize the Company’s capital structure and cost of capital, thereby improving returns to shareholders, as well as to offset the dilutive impact of share-based awards. Repurchases may be made from time to time in open market purchases or other types of transactions (including prepaid or structured share repurchase programs), subject to certain Board restrictions. In June 2014, the Board renewed the Company’s share repurchase program with an authorization to repurchase up to 100 million shares of its common stock. A summary of common share repurchases for the years ended December 31, 2016 and 2015 is as follows: Years Ended December 31, (in millions, except per share data) 2016 2015 Common share repurchases, shares 10 11 Common share repurchases, average price per share $ 128.97 $ 112.45 Common share repurchases, aggregate cost $ 1,280 $ 1,200 Board authorized shares remaining 51 61 Dividends In June 2016, the Company’s Board of Directors increased the Company’s quarterly cash dividend to shareholders to equal an annual dividend rate of $2.50 per share compared to the annual dividend rate of $2.00 per share, which the Company had paid since June 2015. 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.

Share-Based Compensation (Notes

Share-Based Compensation (Notes)	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]	Share-Based Compensation The Company’s outstanding share-based awards consist mainly of non-qualified stock options, SARs and restricted shares. As of December 31, 2016 , the Company had 68 million shares available for future grants of share-based awards under the Plan. As of December 31, 2016 , there were also 10 million shares of common stock available for issuance under the ESPP. Stock Options and SARs Stock option and SAR activity for the year ended December 31, 2016 is summarized in the table below: Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Life Aggregate Intrinsic Value (in millions) (in years) (in millions) Outstanding at beginning of period 34 $ 68 Granted 11 113 Exercised (8 ) 57 Forfeited (1 ) 103 Outstanding at end of period 36 84 6.6 $ 2,758 Exercisable at end of period 14 56 4.0 1,458 Vested and expected to vest, end of period 35 83 6.6 2,704 Restricted Shares Restricted share activity for the year ended December 31, 2016 is summarized in the table below: (shares in millions) Shares Weighted-Average Grant Date Fair Value per Share Nonvested at beginning of period 7 $ 82 Granted 3 115 Vested (3 ) 76 Nonvested at end of period 7 96 Other Share-Based Compensation Data (in millions, except per share amounts) For the Years Ended December 31, 2016 2015 2014 Stock Options and SARs Weighted-average grant date fair value of shares granted, per share $ 20 $ 22 $ 22 Total intrinsic value of stock options and SARs exercised 595 482 526 Restricted Shares Weighted-average grant date fair value of shares granted, per share 115 110 71 Total fair value of restricted shares vested $ 274 $ 460 $ 437 Employee Stock Purchase Plan Number of shares purchased 2 2 2 Share-Based Compensation Items Share-based compensation expense, before tax $ 485 $ 406 $ 364 Share-based compensation expense, net of tax effects 417 348 314 Income tax benefit realized from share-based award exercises 236 247 231 (in millions, except years) December 31, 2016 Unrecognized compensation expense related to share awards $ 516 Weighted-average years to recognize compensation expense 1.3 Share-Based Compensation Recognition and Estimates The principal assumptions the Company used in calculating grant-date fair value for stock options and SARs were as follows: For the Years Ended December 31, 2016 2015 2014 Risk-free interest rate 1.2% - 1.4% 1.6% - 1.7% 1.7% - 1.8% Expected volatility 20.8% - 22.5% 22.3% - 24.1% 24.1% - 39.6% Expected dividend yield 1.8% 1.4% - 1.7% 1.6% - 1.9% Forfeiture rate 5.0% 5.0% 5.0% Expected life in years 5.6 - 5.9 5.5 - 6.1 5.4 Risk-free interest rates are based on U.S. Treasury yields in effect at the time of grant. Expected volatilities are based on the historical volatility of the Company’s common stock and the implied volatility from exchange-traded options on the Company’s common stock. Expected dividend yields are based on the per share cash dividend paid by the Company. The Company uses historical data to estimate option and SAR exercises and forfeitures within the valuation model. The expected lives of options and SARs granted represents the period of time that the awards granted are expected to be outstanding based on historical exercise patterns. Other Employee Benefit Plans The Company also offers a 401(k) plan for its employees. Compensation expense related to this plan was not material for 2016, 2015 and 2014. In addition, the Company maintains non-qualified, deferred compensation plans, which allow certain members of senior management and executives to defer portions of their salary or bonus and receive certain Company contributions on such deferrals, subject to plan limitations. The deferrals are recorded within long-term investments with an approximately equal amount in other liabilities in the Consolidated Balance Sheets. The total deferrals are distributable based upon termination of employment or other periods, as elected under each plan and were $672 million and $553 million as of December 31, 2016 and 2015 , respectively.

Commitments and Contingencies (

Commitments and Contingencies (Notes)	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies Disclosure [Text Block]	Commitments and Contingencies The Company leases facilities and equipment under long-term operating leases that are non-cancelable and expire on various dates. Rent expense under all operating leases for the years ended December 31, 2016 , 2015 and 2014 was $608 million , $555 million and $449 million , respectively. As of December 31, 2016 , future minimum annual lease payments, net of sublease income, under all non-cancelable operating leases were as follows: (in millions) Future Minimum Lease Payments 2017 $ 453 2018 416 2019 355 2020 314 2021 273 Thereafter 499 The Company provides guarantees related to its service level under certain contracts. If minimum standards are not met, the Company may be financially at risk up to a stated percentage of the contracted fee or a stated dollar amount. None of the amounts accrued, paid or charged to income for service level guarantees were material as of December 31, 2016, 2015 or 2014. As of December 31, 2016, the Company had outstanding, undrawn letters of credit with financial institutions of $28 million and surety bonds outstanding with insurance companies of $1.2 billion , primarily to bond contractual performance. Legal Matters Because of the nature of its businesses, the Company is frequently made party to a variety of legal actions and regulatory inquiries, including class actions and suits brought by members, care providers, consumer advocacy organizations, customers and regulators, relating to the Company’s businesses, including management and administration of health benefit plans and other services. These matters include medical malpractice, employment, intellectual property, antitrust, privacy and contract claims and claims related to health care benefits coverage and other business practices. The Company records liabilities for its estimates of probable costs resulting from these matters where appropriate. Estimates of costs resulting from legal and regulatory matters involving the Company are inherently difficult to predict, particularly where the matters: involve indeterminate claims for monetary damages or may involve fines, penalties or punitive damages; present novel legal theories or represent a shift in regulatory policy; involve a large number of claimants or regulatory bodies; are in the early stages of the proceedings; or could result in a change in business practices. Accordingly, the Company is often unable to estimate the losses or ranges of losses for those matters where there is a reasonable possibility or it is probable that a loss may be incurred. Litigation Matters California Claims Processing Matter. On January 25, 2008, the California Department of Insurance (CDI) issued an Order to Show Cause to PacifiCare Life and Health Insurance Company, a subsidiary of the Company, alleging violations of certain insurance statutes and regulations related to an alleged failure to include certain language in standard claims correspondence, timeliness and accuracy of claims processing, interest payments, care provider contract implementation, care provider dispute resolution and other related matters. Although the Company believes that CDI had never before issued a fine in excess of $8 million , CDI advocated a fine of approximately $325 million in this matter. The matter was the subject of an administrative hearing before a California administrative law judge beginning in December 2009, and in August 2013, the administrative law judge issued a nonbinding proposed decision recommending a fine of $11.5 million . The California Insurance Commissioner rejected the administrative law judge’s recommendation and on June 9, 2014, issued his own decision imposing a fine of approximately $174 million . On July 10, 2014, the Company filed a lawsuit in California state court challenging the Commissioner’s decision. On September 8, 2015, in the first phase of that lawsuit, the California state court issued an order invalidating certain of the regulations the Commissioner had relied upon in issuing his decision and penalty. The Company cannot reasonably estimate the range of loss, if any, that may result from this matter given the procedural status of the dispute, the wide range of possible outcomes, the legal issues presented (including the legal basis for the majority of the alleged violations), the inherent difficulty in predicting a regulatory fine in the event of a remand, and the various remedies and levels of judicial review that remain available to the Company. Government Investigations, Audits and Reviews The Company has been involved or is currently involved in various governmental investigations, audits and reviews. These include routine, regular and special investigations, audits and reviews by the CMS, state insurance and health and welfare departments, the Brazilian national regulatory agency for private health insurance and plans (the Agência Nacional de Saúde Suplementar), state attorneys general, the Office of the Inspector General, the Office of Personnel Management, the Office of Civil Rights, the Government Accountability Office, the Federal Trade Commission, U.S. Congressional committees, the U.S. Department of Justice, the SEC, the Internal Revenue Service, the U.S. Drug Enforcement Administration, the Brazilian federal revenue service (the Secretaria da Receita Federal), the U.S. Department of Labor, the Federal Deposit Insurance Corporation, the Defense Contract Audit Agency and other governmental authorities. Certain of the Company’s businesses have been reviewed or are currently under review, including for, among other matters, compliance with coding and other requirements under the Medicare risk-adjustment model. The Company has produced documents, information and witnesses to the Department of Justice in cooperation with a current review of the Company’s risk-adjustment processes, including the Company’s patient chart review and related programs. CMS has selected certain of the Company’s local plans for risk adjustment data validation (RADV) audits to validate the coding practices of and supporting documentation maintained by health care providers and such audits may result in retrospective adjustments to payments made to the Company’s health plans. The Company cannot reasonably estimate the range of loss, if any, that may result from any material government investigations, audits and reviews in which it is currently involved given the status of the reviews, the wide range of possible outcomes and the inherent difficulty in predicting regulatory action, fines and penalties, if any, the Company’s legal and factual defenses and the various remedies and levels of judicial review available to the Company in the event of an adverse finding. Guaranty Fund Assessments Under state guaranty association laws, certain insurance companies can be assessed (up to prescribed limits) for certain obligations to the policyholders and claimants of impaired or insolvent insurance companies that write the same line or similar lines of business. Some states have similar laws relating to HMOs and other payers such as consumer operated and oriented plans (co-ops) established under the ACA. In 2009, the Pennsylvania Insurance Commissioner placed long term care insurer Penn Treaty Network America Insurance Company and its subsidiary (Penn Treaty), neither of which is affiliated with the Company, in rehabilitation and petitioned a state court for approval to liquidate Penn Treaty. In 2012, the court denied the liquidation petition and ordered the Insurance Commissioner to submit a rehabilitation plan. A second amended plan of rehabilitation was later withdrawn and, as of November 2016, Penn Treaty will be liquidated. As of December 31, 2016, the Company recorded the $350 million impact of its estimated share of guaranty association assessments resulting from the Penn Treaty liquidation.

Segment Financial Information (

Segment Financial Information (Notes)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Segment Financial Information [Text Block]	Segment Financial Information Factors used to determine the Company’s reportable segments include the nature of operating activities, economic characteristics, existence of separate senior management teams and the type of information used by the Company’s chief operating decision maker to evaluate its results of operations. Reportable segments with similar economic characteristics, products and services, customers, distribution methods and operational processes that operate in a similar regulatory environment are combined. The following is a description of the types of products and services from which each of the Company’s four reportable segments derives its revenues: • UnitedHealthcare includes the combined results of operations of UnitedHealthcare Employer & Individual, UnitedHealthcare Medicare & Retirement, UnitedHealthcare Community & State and UnitedHealthcare Global. The U.S. businesses share significant common assets, including a contracted network of physicians, health care professionals, hospitals and other facilities, information technology infrastructure and other resources. UnitedHealthcare Employer & Individual offers an array of consumer-oriented health benefit plans and services for large national employers, public sector employers, mid-sized employers, small businesses and individuals nationwide and active and retired military and their families through the TRICARE program. UnitedHealthcare Medicare & Retirement provides health care coverage and health and well-being services to individuals age 50 and older, addressing their unique needs for preventive and acute health care services as well as services dealing with chronic disease and other specialized issues for older individuals. UnitedHealthcare Community & State’s primary customers oversee Medicaid plans, the Children’s Health Insurance Program and other federal, state and community health care programs. UnitedHealthcare Global is a diversified global health services business with a variety of offerings, including international commercial health and dental benefits. • OptumHealth serves the physical, emotional and health-related financial needs of individuals, enabling population health management through programs offered by employers, payers, government entities and directly with the care delivery system. OptumHealth offers access to networks of care provider specialists, health management services, care delivery, consumer engagement and financial services. • OptumInsight provides services, technology and health care expertise to major participants in the health care industry. Hospital systems, physicians, health plans, governments, life sciences companies and other organizations that comprise the health care industry depend on OptumInsight to help them improve performance, achieve efficiency, reduce costs, meet compliance mandates and modernize their core operating systems to meet the changing needs of the health system. • OptumRx offers pharmacy care services and programs, including retail network contracting, home delivery and specialty pharmacy services, purchasing and clinical capabilities, and develops programs in areas such as step therapy, formulary management, drug adherence and disease/drug therapy management. The Company’s accounting policies for reportable segment operations are consistent with those described in the Summary of Significant Accounting Policies (see Note 2 ). Transactions between reportable segments principally consist of sales of pharmacy care products and services to UnitedHealthcare customers by OptumRx, certain product offerings and care management and local care delivery services sold to UnitedHealthcare by OptumHealth, and health information and technology solutions, consulting and other services sold to UnitedHealthcare by OptumInsight. These transactions are recorded at management’s estimate of fair value. Intersegment transactions are eliminated in consolidation. Assets and liabilities that are jointly used are assigned to each reportable segment using estimates of pro-rata usage. Cash and investments are assigned such that each reportable segment has working capital and/or at least minimum specified levels of regulatory capital. As a percentage of the Company’s total consolidated revenues, premium revenues from CMS were 25% for 2016, 26% for 2015 and 29% for 2014, most of which were generated by UnitedHealthcare Medicare & Retirement and included in the UnitedHealthcare segment. U.S. customer revenue represented approximately 97% , 96% and 95% of consolidated total revenues for 2016, 2015 and 2014, respectively. Long-lived fixed assets located in the United States represented approximately 75% and 81% of the total long-lived fixed assets as of December 31, 2016 and 2015, respectively. The non-U.S. revenues and fixed assets are primarily related to UnitedHealthcare Global. The following table presents the reportable segment financial information: Optum (in millions) UnitedHealthcare OptumHealth OptumInsight OptumRx Optum Eliminations Optum Corporate and Eliminations Consolidated 2016 Revenues - external customers: Premiums $ 140,455 $ 3,663 $ — $ — $ — $ 3,663 $ — $ 144,118 Products 1 48 103 26,506 — 26,657 — 26,658 Services 7,514 2,498 2,670 554 — 5,722 — 13,236 Total revenues - external customers 147,970 6,209 2,773 27,060 — 36,042 — 184,012 Total revenues - intersegment — 10,491 4,559 33,372 (1,088 ) 47,334 (47,334 ) — Investment and other income 611 208 1 8 — 217 — 828 Total revenues $ 148,581 $ 16,908 $ 7,333 $ 60,440 $ (1,088 ) $ 83,593 $ (47,334 ) $ 184,840 Earnings from operations $ 7,307 $ 1,428 $ 1,513 $ 2,682 $ — $ 5,623 $ — $ 12,930 Interest expense — — — — — — (1,067 ) (1,067 ) Earnings before income taxes $ 7,307 $ 1,428 $ 1,513 $ 2,682 $ — $ 5,623 $ (1,067 ) $ 11,863 Total assets $ 70,505 $ 18,656 $ 9,017 $ 29,066 $ — $ 56,739 $ (4,434 ) $ 122,810 Purchases of property, equipment and capitalized software 640 345 571 149 — 1,065 — 1,705 Depreciation and amortization 724 297 559 475 — 1,331 — 2,055 2015 Revenues - external customers: Premiums $ 124,011 $ 3,152 $ — $ — $ — $ 3,152 $ — $ 127,163 Products 2 31 108 17,171 — 17,310 — 17,312 Services 6,776 2,375 2,390 381 — 5,146 — 11,922 Total revenues - external customers 130,789 5,558 2,498 17,552 — 25,608 — 156,397 Total revenues - intersegment — 8,216 3,697 30,718 (791 ) 41,840 (41,840 ) — Investment and other income 554 153 1 2 — 156 — 710 Total revenues $ 131,343 $ 13,927 $ 6,196 $ 48,272 $ (791 ) $ 67,604 $ (41,840 ) $ 157,107 Earnings from operations $ 6,754 $ 1,240 $ 1,278 $ 1,749 $ — $ 4,267 $ — $ 11,021 Interest expense — — — — — — (790 ) (790 ) Earnings before income taxes $ 6,754 $ 1,240 $ 1,278 $ 1,749 $ — $ 4,267 $ (790 ) $ 10,231 Total assets (a) $ 64,212 $ 14,600 $ 8,335 $ 26,844 $ — $ 49,779 $ (2,737 ) $ 111,254 Purchases of property, equipment and capitalized software 653 252 572 79 — 903 — 1,556 Depreciation and amortization 718 251 492 232 — 975 — 1,693 2014 Revenues - external customers: Premiums $ 112,645 $ 2,657 $ — $ — $ — $ 2,657 $ — $ 115,302 Products 3 18 96 4,125 — 4,239 — 4,242 Services 6,516 1,300 2,224 111 — 3,635 — 10,151 Total revenues - external customers 119,164 3,975 2,320 4,236 — 10,531 — 129,695 Total revenues - intersegment — 6,913 2,906 27,740 (489 ) 37,070 (37,070 ) — Investment and other income 634 144 1 — — 145 — 779 Total revenues $ 119,798 $ 11,032 $ 5,227 $ 31,976 $ (489 ) $ 47,746 $ (37,070 ) $ 130,474 Earnings from operations $ 6,992 $ 1,090 $ 1,002 $ 1,190 $ — $ 3,282 $ — $ 10,274 Interest expense — — — — — — (618 ) (618 ) Earnings before income taxes $ 6,992 $ 1,090 $ 1,002 $ 1,190 $ — $ 3,282 $ (618 ) $ 9,656 Total assets (a) $ 62,405 $ 11,148 $ 8,112 $ 5,474 $ — $ 24,734 $ (839 ) $ 86,300 Purchases of property, equipment and capitalized software 773 212 484 56 — 752 — 1,525 Depreciation and amortization 772 179 433 94 — 706 — 1,478 (a) In the first quarter of 2016, the Company adopted ASU 2015-03, retrospectively as required. See Note 2 for more information on the adoption of ASU 2015-03.

Quarterly Financial Data (Unaud

Quarterly Financial Data (Unaudited) (Notes)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information [Text Block]	Quarterly Financial Data (Unaudited) Selected quarterly financial information for all quarters of 2016 and 2015 is as follows: For the Quarter Ended (in millions, except per share data) March 31 June 30 September 30 December 31 2016 Revenues $ 44,527 $ 46,485 $ 46,293 $ 47,535 Operating costs 41,567 43,282 42,713 44,348 Earnings from operations 2,960 3,203 3,580 3,187 Net earnings 1,627 1,760 1,978 1,708 Net earnings attributable to UnitedHealth Group common shareholders 1,611 1,754 1,968 1,684 Net earnings per share attributable to UnitedHealth Group common shareholders: Basic 1.69 1.84 2.07 1.77 Diluted 1.67 1.81 2.03 1.74 2015 Revenues $ 35,756 $ 36,263 $ 41,489 $ 43,599 Operating costs 33,116 33,368 38,471 41,131 Earnings from operations 2,640 2,895 3,018 2,468 Net earnings 1,413 1,585 1,618 1,252 Net earnings attributable to UnitedHealth Group common shareholders 1,413 1,585 1,597 1,218 Net earnings per share attributable to UnitedHealth Group common shareholders: Basic 1.48 1.66 1.68 1.28 Diluted 1.46 1.64 1.65 1.26

Schedule I (Notes)

Schedule I (Notes)	12 Months Ended
	Dec. 31, 2016
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Financial Information of Parent Company Only Disclosure [Text Block]	Schedule I Condensed Financial Information of Registrant (Parent Company Only) UnitedHealth Group Condensed Balance Sheets (in millions, except per share data) December 31, December 31, Assets Current assets: Cash and cash equivalents $ 180 $ 29 Short-term notes receivable from subsidiaries 755 — Other current assets 140 313 Total current assets 1,075 342 Equity in net assets of subsidiaries 60,593 56,316 Long-term notes receivable from subsidiaries 9,912 9,679 Other assets 248 199 Total assets $ 71,828 $ 66,536 Liabilities and shareholders’ equity Current liabilities: Accounts payable and accrued liabilities $ 452 $ 449 Note payable to subsidiary 280 310 Commercial paper and current maturities of long-term debt 7,113 6,587 Total current liabilities 7,845 7,346 Long-term debt, less current maturities 25,657 25,215 Other liabilities 52 145 Total liabilities 33,554 32,706 Commitments and contingencies (Note 4) Shareholders’ equity: Preferred stock, $0.001 par value -10 shares authorized; no shares issued or outstanding — — Common stock, $0.01 par value - 3,000 shares authorized; 952 and 953 issued and outstanding 10 10 Additional paid-in capital — 29 Retained earnings 40,945 37,125 Accumulated other comprehensive loss (2,681 ) (3,334 ) Total UnitedHealth Group shareholders’ equity 38,274 33,830 Total liabilities and shareholders’ equity $ 71,828 $ 66,536 See Notes to the Condensed Financial Statements of Registrant Schedule I Condensed Financial Information of Registrant (Parent Company Only) UnitedHealth Group Condensed Statements of Comprehensive Income For the Years Ended December 31, (in millions) 2016 2015 2014 Revenues: Investment and other income $ 522 $ 396 $ 293 Total revenues 522 396 293 Operating costs: Operating costs (22 ) (17 ) 1 Interest expense 995 717 554 Total operating costs 973 700 555 Loss before income taxes (451 ) (304 ) (262 ) Benefit for income taxes 165 111 96 Loss of parent company (286 ) (193 ) (166 ) Equity in undistributed income of subsidiaries 7,303 6,006 5,785 Net earnings 7,017 5,813 5,619 Other comprehensive income (loss) 653 (1,942 ) (484 ) Comprehensive income $ 7,670 $ 3,871 $ 5,135 See Notes to the Condensed Financial Statements of Registrant Schedule I Condensed Financial Information of Registrant (Parent Company Only) UnitedHealth Group Condensed Statements of Cash Flows For the Years Ended December 31, (in millions) 2016 2015 2014 Operating activities Cash flows from operating activities $ 4,294 $ 1,727 $ 7,445 Investing activities Issuance of notes to subsidiaries (824 ) (5,064 ) (436 ) Cash paid for acquisitions (2,292 ) (12,270 ) (1,852 ) Return of capital to parent company 2,143 4,375 — Capital contributions to subsidiaries (765 ) (1,109 ) (704 ) Other, net 168 140 (9 ) Cash flows used for investing activities (1,570 ) (13,928 ) (3,001 ) Financing activities Common stock repurchases (1,280 ) (1,200 ) (4,008 ) Proceeds from common stock issuances 429 402 462 Cash dividends paid (2,261 ) (1,786 ) (1,362 ) (Repayments of) proceeds from commercial paper, net (382 ) 3,666 (794 ) Proceeds from issuance of long-term debt 3,968 11,982 1,997 Repayments of long-term debt (2,596 ) (1,041 ) (812 ) Other, net (451 ) (352 ) (190 ) Cash flows (used for) from financing activities (2,573 ) 11,671 (4,707 ) Increase (decrease) in cash and cash equivalents 151 (530 ) (263 ) Cash and cash equivalents, beginning of period 29 559 822 Cash and cash equivalents, end of period $ 180 $ 29 $ 559 Supplemental cash flow disclosures Cash paid for interest $ 974 $ 573 $ 578 Cash paid for income taxes 4,557 4,294 4,028 See Notes to the Condensed Financial Statements of Registrant Schedule I Condensed Financial Information of Registrant (Parent Company Only) UnitedHealth Group Notes to Condensed Financial Statements 1. Basis of Presentation UnitedHealth Group’s parent company financial information has been derived from its consolidated financial statements and should be read in conjunction with the consolidated financial statements included in this Form 10-K. The accounting policies for the registrant are the same as those described in Note 2 of Notes to the Consolidated Financial Statements included in Part II, Item 8, “Financial Statements.” 2. Subsidiary Transactions Investment in Subsidiaries. UnitedHealth Group’s investment in subsidiaries is stated at cost plus equity in undistributed earnings of subsidiaries. Intercompany Notes. In July 2015, the parent company issued $4.8 billion in intercompany notes that were used to partially fund the acquisition of Catamaran. See Note 6 of Notes to the Consolidated Financial Statements included in Part II, Item 8, “Financial Statements” for more information about Catamaran. Dividends and Capital Distributions. Cash dividends received from subsidiaries and included in Cash Flows from Operating Activities in the Condensed Statements of Cash Flows were $3.7 billion , $4.8 billion and $5.5 billion in 2016, 2015 and 2014, respectively. Additionally, $2.1 billion and $4.4 billion in cash were received as a return of capital to the parent company during 2016 and 2015, respectively. 3. Commercial Paper and Long-Term Debt Discussion of commercial paper and long-term debt can be found in Note 8 of Notes to the Consolidated Financial Statements included in Part II, Item 8, “Financial Statements.” Long-term debt obligations of the parent company do not include other financing obligations at subsidiaries that totaled $200 million and $164 million at December 31, 2016 and 2015, respectively. Maturities of commercial paper and long-term debt for the years ending December 31 are as follows: (in millions) 2017 $ 7,105 2018 2,600 2019 1,750 2020 1,950 2021 2,400 Thereafter 17,217 4. Commitments and Contingencies For a summary of commitments and contingencies, see Note 12 of Notes to the Consolidated Financial Statements included in Part II, Item 8, “Financial Statements.”

Basis of Presentation, Uses o23

Basis of Presentation, Uses of Estimates and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation The Company has prepared the Consolidated Financial Statements according to U.S. Generally Accepted Accounting Principles (GAAP) and has included the accounts of UnitedHealth Group and its subsidiaries.
Use of Estimates, Policy [Policy Text Block]	Use of Estimates These Consolidated Financial Statements include certain amounts based on the Company’s best estimates and judgments. The Company’s most significant estimates relate to estimates and judgments for medical costs payable and revenues, valuation and impairment analysis of goodwill and other intangible assets, estimates of other current liabilities and other current receivables and valuations of certain investments. Certain of these estimates require the application of complex assumptions and judgments, often because they involve matters that are inherently uncertain and will likely change in subsequent periods. The impact of any change in estimates is included in earnings in the period in which the estimate is adjusted.
Revenue Recognition, Policy [Policy Text Block]	Revenues Premiums Premium revenues are primarily derived from risk-based health insurance arrangements in which the premium is typically at a fixed rate per individual served for a one-year period, and the Company assumes the economic risk of funding its customers’ health care and related administrative costs. Premium revenues are recognized in the period in which eligible individuals are entitled to receive health care benefits. Health care premium payments received from the Company’s customers in advance of the service period are recorded as unearned revenues. Fully insured commercial products of U.S. health plans, Medicare Advantage and Medicare Prescription Drug Benefit (Medicare Part D) plans with medical loss ratios as calculated under the definitions in the Patient Protection and Affordable Care Act (ACA) and related federal and state regulations and implementing regulations, that fall below certain targets are required to rebate ratable portions of their premiums annually. Medicare Advantage premium revenue includes the impact of Centers for Medicare & Medicaid Services (CMS) quality bonuses based on plans’ Star ratings. Premium revenues are recognized based on the estimated premiums earned net of projected rebates because the Company is able to reasonably estimate the ultimate premiums of these contracts. The Company also records premium revenues from capitation arrangements at its OptumHealth businesses. The Company’s Medicare Advantage and Medicare Part D premium revenues are subject to periodic adjustment under CMS’ risk adjustment payment methodology. CMS deploys a risk adjustment model that apportions premiums paid to all health plans according to health severity and certain demographic factors. The CMS risk adjustment model provides higher per member payments for enrollees diagnosed with certain conditions and lower payments for enrollees who are healthier. Under this risk adjustment methodology, CMS calculates the risk adjusted premium payment using diagnosis data from hospital inpatient, hospital outpatient and physician treatment settings. The Company and health care providers collect, capture and submit the necessary and available diagnosis data to CMS within prescribed deadlines. The Company estimates risk adjustment revenues based upon the diagnosis data submitted and expected to be submitted to CMS. Risk adjustment data for certain of the Company’s plans are subject to review by the government, including audit by regulators. See Note 12 for additional information regarding these audits. Products and Services For the Company’s OptumRx pharmacy care services business, the majority of revenues are derived from products sold through a contracted network of retail pharmacies or home delivery and specialty pharmacy facilities. Product revenues include ingredient costs (net of rebates), a negotiated dispensing fee and customer co-payments for drugs dispensed through the Company’s mail-service pharmacy. In retail pharmacy transactions, revenues recognized exclude the member’s applicable co-payment. Pharmacy products are billed to customers based on the number of transactions occurring during the billing period. Product revenues are recognized when the prescriptions are dispensed through the retail network or received by consumers through the Company’s mail-service pharmacy. The Company has entered into contracts in which it is primarily obligated to pay its network pharmacy providers for benefits provided to their customers regardless of whether the Company is paid. The Company is also involved in establishing the prices charged by retail pharmacies, determining which drugs will be included in formulary listings and selecting which retail pharmacies will be included in the network offered to plan sponsors’ members. As a result, revenues are reported on a gross basis. Services revenue consists of fees derived from services performed for customers that self-insure the health care costs of their employees and employees’ dependents. Under service fee contracts, the Company receives monthly, a fixed fee per employee, which is recognized as revenue as the Company performs, or makes available the applicable services to the customer. The customers retain the risk of financing health care costs for their employees and employees’ dependents, and the Company administers the payment of customer funds to physicians and other health care professionals from customer-funded bank accounts. As the Company has neither the obligation for funding the health care costs, nor the primary responsibility for providing the medical care, the Company does not recognize premium revenue and medical costs for these contracts in its Consolidated Financial Statements. For these fee-based customer arrangements, the Company provides coordination and facilitation of medical services; transaction processing; customer, consumer and care professional services; and access to contracted networks of physicians, hospitals and other health care professionals. These services are performed throughout the contract period. Revenues are also comprised of a number of services and products sold through Optum. For its financial services offerings, OptumHealth charges fees and earns investment income on managed funds. OptumInsight provides software and information products, advisory consulting arrangements and services outsourcing contracts, which may be delivered over several years. OptumInsight revenues are generally recognized over time on either a time and materials basis, or ratably as services are performed or made available to customers.
Medical Costs and Medical Costs Payable [Policy Text Block]	Medical Costs and Medical Costs Payable The Company’s estimate of medical costs payable represents management’s best estimate of its liability for unpaid medical costs as of December 31, 2016. Each period, the Company re-examines previously established medical costs payable estimates based on actual claim submissions and other changes in facts and circumstances. As more complete claim information becomes available, the Company adjusts the amount of the estimates and includes the changes in estimates in medical costs in the period in which the change is identified. Approximately 90% of claims related to medical care services are known and settled within 90 days from the date of service and substantially all within twelve months. Medical costs and medical costs payable include estimates of the Company’s obligations for medical care services that have been rendered on behalf of insured consumers, but for which claims have either not yet been received, processed, or paid. The Company develops estimates for medical care services incurred but not reported (IBNR), which includes estimates for claims that have not been received or fully processed, using an actuarial process that is consistently applied, centrally controlled and automated. The actuarial models consider factors such as time from date of service to claim processing, seasonal variances in medical care consumption, health care professional contract rate changes, medical care utilization and other medical cost trends, membership volume and demographics, the introduction of new technologies, benefit plan changes, and business mix changes related to products, customers and geography. In developing its medical costs payable estimates, the Company applies different estimation methods depending on which incurred claims are being estimated. For the most recent two months, the Company estimates claim costs incurred by applying observed medical cost trend factors to the average per member per month (PMPM) medical costs incurred in prior months for which more complete claim data are available, supplemented by a review of near-term completion factors (actuarial estimates, based upon historical experience and analysis of current trends, of the percentage of incurred claims during a given period that have been adjudicated by the Company at the date of estimation). For months prior to the most recent two months, the Company applies the completion factors to actual claims adjudicated-to-date to estimate the expected amount of ultimate incurred claims for those months.
Cost of Sales, Policy [Policy Text Block]	Cost of Products Sold The Company’s cost of products sold includes the cost of pharmaceuticals dispensed to unaffiliated customers either directly at its mail and specialty pharmacy locations, or indirectly through its nationwide network of participating pharmacies. Rebates attributable to non-affiliated clients are accrued as rebates receivable and a reduction of cost of products sold with a corresponding payable for the amounts of the rebates to be remitted to those non-affiliated clients in accordance with their contracts and recorded in the Consolidated Statements of Operations as a reduction of product revenue. Cost of products sold also includes the cost of personnel to support the Company’s transaction processing services, system sales, maintenance and professional services.
Cash and Cash Equivalents, Policy [Policy Text Block]	Cash, Cash Equivalents and Investments Cash and cash equivalents are highly liquid investments that have an original maturity of three months or less. The fair value of cash and cash equivalents approximates their carrying value because of the short maturity of the instruments.
Investment, Policy [Policy Text Block]	Investments with maturities of less than one year are classified as short-term. Because of regulatory requirements, certain investments are included in long-term investments regardless of their maturity date. The Company classifies these investments as held-to-maturity and reports them at amortized cost. Substantially all other investments are classified as available-for-sale and reported at fair value based on quoted market prices, where available. The Company excludes unrealized gains and losses on investments in available-for-sale securities from net earnings and reports them as comprehensive income and, net of income tax effects, as a separate component of equity. To calculate realized gains and losses on the sale of investments, the Company specifically identifies the cost of each investment sold. The Company evaluates an investment for impairment by considering the length of time and extent to which market value has been less than cost or amortized cost, the financial condition and near-term prospects of the issuer as well as specific events or circumstances that may influence the operations of the issuer and the Company’s intent to sell the security or the likelihood that it will be required to sell the security before recovery of the entire amortized cost. New information and the passage of time can change these judgments. The Company manages its investment portfolio to limit its exposure to any one issuer or market sector, and largely limits its investments to investment grade quality. Securities downgraded below policy minimums after purchase will be disposed of in accordance with the Company’s investment policy. Investments with maturities of less than one year are classified as short-term. Because of regulatory requirements, certain investments are included in long-term investments regardless of their maturity date. The Company classifies these investments as held-to-maturity and reports them at amortized cost. Substantially all other investments are classified as available-for-sale and reported at fair value based on quoted market prices, where available. The Company excludes unrealized gains and losses on investments in available-for-sale securities from net earnings and reports them as comprehensive income and, net of income tax effects, as a separate component of equity. To calculate realized gains and losses on the sale of investments, the Company specifically identifies the cost of each investment sold. The Company evaluates an investment for impairment by considering the length of time and extent to which market value has been less than cost or amortized cost, the financial condition and near-term prospects of the issuer as well as specific events or circumstances that may influence the operations of the issuer and the Company’s intent to sell the security or the likelihood that it will be required to sell the security before recovery of the entire amortized cost. New information and the passage of time can change these judgments. The Company manages its investment portfolio to limit its exposure to any one issuer or market sector, and largely limits its investments to investment grade quality. Securities downgraded below policy minimums after purchase will be disposed of in accordance with the Company’s investment policy.
AARP Assets Under Management [Policy Text Block]	Assets Under Management The Company provides health insurance products and services to members of AARP under a Supplemental Health Insurance Program (the AARP Program) and to AARP members and non-members under separate Medicare Advantage and Medicare Part D arrangements. The products and services under the AARP Program include supplemental Medicare benefits, hospital indemnity insurance, including insurance for individuals between 50 to 64 years of age and other related products. Pursuant to the Company’s agreement, AARP Program assets are managed separately from the Company’s general investment portfolio and are used to pay costs associated with the AARP Program. These assets are invested at the Company’s discretion, within investment guidelines approved by AARP. The Company does not guarantee any rates of return on these investments and, upon any transfer of the AARP Program contract to another entity, the Company would transfer cash equal in amount to the fair value of these investments at the date of transfer to that entity. Because the purpose of these assets is to fund the medical costs payable, the rate stabilization fund (RSF) liabilities and other related liabilities associated with this AARP contract, assets under management are classified as current assets, consistent with the classification of these liabilities. The effects of changes in other balance sheet amounts associated with the AARP Program also accrue to the overall benefit of the AARP policyholders through the RSF balance. Accordingly, the Company excludes the effect of such changes in its Consolidated Statements of Cash Flows.
Receivables, Policy [Policy Text Block]	Other Current Receivables Other current receivables include amounts due from pharmaceutical manufacturers for rebates and Medicare Part D drug discounts and other miscellaneous amounts due to the Company. The Company’s pharmacy care services businesses contract with pharmaceutical manufacturers, some of which provide rebates based on use of the manufacturers’ products by its affiliated and non-affiliated clients. The Company accrues rebates as they are earned by its clients on a monthly basis based on the terms of the applicable contracts, historical data and current estimates. The pharmacy care services businesses bill these rebates to the manufacturers on a monthly or quarterly basis depending on the contractual terms and records rebates attributable to affiliated clients as a reduction to medical costs. The Company generally receives rebates from two to five months after billing. As of December 31, 2016 and 2015, total pharmaceutical manufacturer rebates receivable included in other receivables in the Consolidated Balance Sheets amounted to $ 3.3 billion and $2.6 billion , respectively. For details on the Company’s Medicare Part D receivables see “Medicare Part D Pharmacy Benefits” below.
Medicare Part D Policy [Policy Text Block]	Medicare Part D Pharmacy Benefits The Company serves as a plan sponsor offering Medicare Part D prescription drug insurance coverage under contracts with CMS. Under the Medicare Part D program, there are seven separate elements of payment received by the Company during the plan year. These payment elements are as follows: • CMS Premium. CMS pays a fixed monthly premium per member to the Company for the entire plan year. • Member Premium. Additionally, certain members pay a fixed monthly premium to the Company for the entire plan year. • Low-Income Premium Subsidy. For qualifying low-income members, CMS pays some or all of the member’s monthly premiums to the Company on the member’s behalf. • Catastrophic Reinsurance Subsidy . CMS pays the Company a cost reimbursement estimate monthly to fund the CMS obligation to pay approximately 80% of the costs incurred by individual members in excess of the individual annual out-of-pocket maximum. A settlement is made with CMS based on actual cost experience, after the end of the plan year. • Low-Income Member Cost Sharing Subsidy. For qualifying low-income members, CMS pays on the member’s behalf some or all of a member’s cost sharing amounts, such as deductibles and coinsurance. The cost sharing subsidy is funded by CMS through monthly payments to the Company. The Company administers and pays the subsidized portion of the claims on behalf of CMS, and a settlement payment is made between CMS and the Company based on actual claims and premium experience, after the end of the plan year. • CMS Risk-Share. Premiums from CMS are subject to risk corridor provisions that compare costs targeted in the Company’s annual bids by product and region to actual prescription drug costs, limited to actual costs that would have been incurred under the standard coverage as defined by CMS. Variances of more than 5% above or below the original bid submitted by the Company may result in CMS making additional payments to the Company or require the Company to refund to CMS a portion of the premiums it received. The Company estimates and recognizes an adjustment to premium revenues related to the risk corridor payment settlement based upon pharmacy claims experience to date. The estimate of the settlement associated with these risk corridor provisions requires the Company to consider factors that may not be certain, including estimates of eligible pharmacy costs and member eligibility status differences with CMS. The Company records risk-share adjustments to premium revenues in the Consolidated Statements of Operations and other current liabilities or other current receivables in the Consolidated Balance Sheets. • Drug Discount. The ACA mandated a consumer discount on brand name prescription drugs for Medicare Part D plan participants in the coverage gap. This discount is funded by CMS and pharmaceutical manufacturers while the Company administers the application of these funds. Accordingly, amounts received are not reflected as premium revenues, but rather are accounted for as deposits. The Company records a liability when amounts are received from CMS and a receivable when the Company bills the pharmaceutical manufacturers. Related cash flows are presented as customer funds administered within financing activities in the Consolidated Statements of Cash Flows. The CMS Premium, the Member Premium and the Low-Income Premium Subsidy represent payments for the Company’s insurance risk coverage under the Medicare Part D program and, therefore, are recorded as premium revenues in the Consolidated Statements of Operations. Premium revenues are recognized ratably over the period in which eligible individuals are entitled to receive prescription drug benefits. The Company records premium payments received in advance of the applicable service period in unearned revenues in the Consolidated Balance Sheets. The Catastrophic Reinsurance Subsidy and the Low-Income Member Cost Sharing Subsidy (Subsidies) represent cost reimbursements under the Medicare Part D program. Amounts received for these Subsidies are not reflected as premium revenues, but rather are accounted for as receivables and/or deposits. Related cash flows are presented as customer funds administered within financing activities in the Consolidated Statements of Cash Flows. Pharmacy care costs and administrative costs under the contract are expensed as incurred and are recognized in medical costs and operating costs, respectively, in the Consolidated Statements of Operations. The final 2016 risk-share amount is expected to be settled during the second half of 2017, and is subject to the reconciliation process with CMS. The Consolidated Balance Sheets include the following amounts associated with the Medicare Part D program: December 31, 2016 December 31, 2015 (in millions) Subsidies Drug Discount Risk-Share Subsidies Drug Discount Risk-Share Other current receivables $ 934 $ 543 $ — $ 1,703 $ 423 $ — Other current liabilities — 267 471 — 58 496
Property, Plant and Equipment, Policy [Policy Text Block]	Property, Equipment and Capitalized Software Property, equipment and capitalized software are stated at cost, net of accumulated depreciation and amortization. Capitalized software consists of certain costs incurred in the development of internal-use software, including external direct costs of materials and services and applicable payroll costs of employees devoted to specific software development. The Company calculates depreciation and amortization using the straight-line method over the estimated useful lives of the assets. The useful lives for property, equipment and capitalized software are: Furniture, fixtures and equipment 3 to 7 years Buildings 35 to 40 years Capitalized software 3 to 5 years Leasehold improvements are depreciated over the shorter of the remaining lease term or their estimated useful economic life.
Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block]	Goodwill To determine whether goodwill is impaired, annually or more frequently if needed, the Company performs a multi-step impairment test. The Company may first assess qualitative factors to determine if it is more likely than not that the carrying value of a reporting unit exceeds its estimated fair value. The Company may also elect to skip the qualitative testing and proceed directly to the quantitative testing. When performing quantitative testing, the Company first estimates the fair values of its reporting units using discounted cash flows. To determine fair values, the Company must make assumptions about a wide variety of internal and external factors. Significant assumptions used in the impairment analysis include financial projections of free cash flow (including significant assumptions about operations, capital requirements and income taxes), long-term growth rates for determining terminal value and discount rates. Comparative market multiples are used to corroborate the results of the discounted cash flow test. If the fair value is less than the carrying value of the reporting unit, then the implied value of goodwill would be calculated and compared to the carrying amount of goodwill to determine whether goodwill is impaired. There was no impairment of goodwill during the year ended December 31, 2016 .
Goodwill and Intangible Assets, Intangible Assets, Policy [Policy Text Block]	Intangible Assets The Company’s intangible assets are subject to impairment tests when events or circumstances indicate that an intangible asset (or asset group) may be impaired. The Company’s indefinite lived intangible assets are also tested for impairment annually. There was no impairment of intangible assets during the year ended December 31, 2016 .
Accounts Payable and Accrued Liabilities [Policy Text Block]	Accounts Payable and Accrued Liabilities The Company had checks outstanding of $1.5 billion and $1.6 billion as of December 31, 2016 and 2015, respectively, which were classified as accounts payable and accrued liabilities and the change in this balance has been reflected within other financing activities in the Consolidated Statements of Cash Flows.
Other Current Liabilities [Policy Text Block]	Other Current Liabilities Other current liabilities include health savings account deposits ( $5.7 billion and $3.6 billion as of December 31, 2016 and 2015 , respectively), the RSF associated with the AARP Program, deposits under the Medicare Part D program (see “Medicare Part D Pharmacy Benefits” above), accruals for premium rebate payments under the ACA, the current portion of future policy benefits and customer balances.
Future Policy Benefits Liability, Policy [Policy Text Block]	Future Policy Benefits Future policy benefits represent account balances that accrue to the benefit of the policyholders, excluding surrender charges, for universal life and investment annuity products and for long-duration health policies sold to individuals for which some of the premium received in the earlier years is intended to pay benefits to be incurred in future years.
Deferred Policy Acquisition Costs, Policy [Policy Text Block]	Policy Acquisition Costs The Company’s short duration health insurance contracts typically have a one-year term and may be canceled by the customer with at least 30 days’ notice. Costs related to the acquisition and renewal of short duration customer contracts are charged to expense as incurred.
Consolidation, Subsidiaries or Other Investments, Consolidated Entities, Policy [Policy Text Block]	Redeemable Noncontrolling Interests Redeemable noncontrolling interests in the Company’s subsidiaries whose redemption is outside the control of the Company are classified as temporary equity. The following table provides details of the Company's redeemable noncontrolling interests’ activity for the years ended December 31, 2016 and 2015 : (in millions) 2016 2015 Redeemable noncontrolling interests, beginning of period $ 1,736 $ 1,388 Net earnings 16 29 Acquisitions 34 196 Redemptions (123 ) (116 ) Distributions (11 ) (19 ) Fair value and other adjustments 360 258 Redeemable noncontrolling interests, end of period $ 2,012 $ 1,736
Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]	Share-Based Compensation The Company recognizes compensation expense for share-based awards, including stock options, stock-settled stock appreciation rights (SARs) and restricted stock and restricted stock units (collectively, restricted shares), on a straight-line basis over the related service period (generally the vesting period) of the award, or to an employee’s eligible retirement date under the award agreement, if earlier. Restricted shares vest ratably; primarily over two to five years and compensation expense related to restricted shares is based on the share price on date of grant. Stock options and SARs vest ratably primarily over four years and may be exercised up to 10 years from the date of grant. Compensation expense related to stock options and SARs is based on the fair value at date of grant, which is estimated on the date of grant using a binomial option-pricing model. Under the Company’s Employee Stock Purchase Plan (ESPP) eligible employees are allowed to purchase the Company’s stock at a discounted price, which is 85% of the lower market price of the Company’s common stock at the beginning or at the end of the six-month purchase period. Share-based compensation expense for all programs is recognized in operating costs in the Consolidated Statements of Operations.
Earnings Per Share, Policy [Policy Text Block]	Net Earnings Per Common Share The Company computes basic earnings per common share attributable to UnitedHealth Group common shareholders by dividing net earnings attributable to UnitedHealth Group common shareholders by the weighted-average number of common shares outstanding during the period. The Company determines diluted net earnings per common share attributable to UnitedHealth Group common shareholders using the weighted-average number of common shares outstanding during the period, adjusted for potentially dilutive shares associated with stock options, SARs, restricted shares and the ESPP, (collectively, common stock equivalents) using the treasury stock method. The treasury stock method assumes a hypothetical issuance of shares to settle the share-based awards, with the assumed proceeds used to purchase common stock at the average market price for the period. Assumed proceeds include the amount the employee must pay upon exercise and any unrecognized compensation cost. The difference between the number of shares assumed issued and number of shares assumed purchased represents the dilutive shares.
Health Insurance Industry Tax, Policy [Policy Text Block]	Health Insurance Industry Tax The ACA includes an annual, nondeductible insurance industry tax (Health Insurance Industry Tax) to be levied proportionally across the insurance industry for risk-based health insurance products. The Company estimates its liability for the Health Insurance Industry Tax based on a ratio of the Company’s applicable net premiums written compared to the U.S. health insurance industry total applicable net premiums, both for the previous calendar year. The Company records in full the estimated liability for the Health Insurance Industry Tax at the beginning of the calendar year with a corresponding deferred cost that is amortized to operating costs on the Consolidated Statements of Operations using a straight-line method of allocation over the calendar year. The liability is recorded in accounts payable and accrued liabilities and the corresponding deferred cost is recorded in prepaid expenses and other current assets on the Consolidated Balance Sheets. A provision in the 2016 Federal Budget imposed a one year moratorium for 2017 on the collection of the Health Insurance Industry Tax.
Premium Stabilization Programs, Accounting Policy [Policy Text Block]	Premium Stabilization Programs The ACA included three programs designed to stabilize health insurance markets (Premium Stabilization Programs): a permanent risk adjustment program; a temporary risk corridors program; and a transitional reinsurance program (Reinsurance Program). The risk-adjustment provisions apply to market reform compliant individual and small group plans in the commercial markets. Under the program, each covered member is assigned a risk score based upon demographic information and applicable diagnostic codes from the current year paid claims, in order to determine an average risk score for each plan in a particular state and market risk pool. Generally, a plan with a risk score that is less than the state’s average risk score will pay into the pool, while a plan with a risk score that is greater than the state’s average will receive money from the pool. The temporary risk corridors provisions are intended to limit the gains and losses of individual and small group qualified health plans. Plans are required to calculate the U.S. Department of Health and Human Services (HHS) risk corridor ratio of allowable costs to the defined target amount. Qualified health plans with ratios below 97% are required to make payments to HHS, while plans with ratios greater than 103% expect to receive funds from HHS. The Reinsurance Program and temporary risk corridors program expired at the end of 2016. For the Premium Stabilization Programs, the Company records a receivable or payable as an adjustment to premium revenue based on year-to-date experience when the amounts are reasonably estimable and collection is reasonably assured. Final adjustments or recoverable amounts to the Premium Stabilization Programs are determined by HHS in the year following the policy year.
New Accounting Pronouncements, Policy [Policy Text Block]	Recently Issued Accounting Standards In February 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standard Update (ASU) No. 2016-02, “Leases (Topic 842)” (ASU 2016-02). Under ASU 2016-02, an entity will be required to recognize assets and liabilities for the rights and obligations created by leases on the entity’s balance sheet for both finance and operating leases. For leases with a term of 12 months or less, an entity can elect to not recognize lease assets and lease liabilities and expense the lease over a straight-line basis for the term of the lease. ASU 2016-02 will require new disclosures that depict the amount, timing, and uncertainty of cash flows pertaining to an entity’s leases. Companies are required to adopt the new standard using a modified retrospective approach for annual and interim periods beginning after December 15, 2018. Early adoption of ASU 2016-02 is permitted. When adopted, the Company does not expect ASU 2016-02 to have a material impact on its results of operations, equity or cash flows. The impact of ASU 2016-02 on the Company’s consolidated financial position will be based on leases outstanding at the time of adoption. In January 2016, the FASB issued ASU 2016-01, “Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities” (ASU 2016-01). The new guidance changes the current accounting related to (i) the classification and measurement of certain equity investments, (ii) the presentation of changes in the fair value of financial liabilities measured under the fair value option that are due to instrument-specific credit risk, and (iii) certain disclosures associated with the fair value of financial instruments. Most notably, ASU 2016-01 requires that equity investments, with certain exemptions, be measured at fair value with changes in fair value recognized in net income as opposed to other comprehensive income. The new guidance is effective for annual and interim reporting periods beginning after December 15, 2017. As of December 31, 2016, based on equity securities held, the Company does not expect ASU 2016-01 to have a material impact on its consolidated financial position, results of operations, equity or cash flows. The Company will continue to evaluate any changes in its mix of investments or market conditions and the related impact of ASU 2016-01. In May 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606)” (ASU 2014-09) as modified by ASU No. 2015-14, “Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date,” ASU 2016-08, “Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net),” ASU No. 2016-10, “Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing,” ASU No. 2016-12, “Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients,” and ASU 2016-20, “Revenue from Contracts with Customers (Topic 606): Technical Corrections and Improvements.” ASU 2014-09 will supersede existing revenue recognition standards with a single model unless those contracts are within the scope of other standards (e.g., an insurance entity’s insurance contracts). The revenue recognition principle in ASU 2014-09 is that an entity should recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In addition, new and enhanced disclosures will be required. Companies may adopt the new standard either using the full retrospective approach, a modified retrospective approach with practical expedients, or a cumulative effect upon adoption approach. The Company early adopted the new standard effective January 1, 2017, as allowed, using the modified retrospective approach. As the majority of the Company’s revenues are not subject to the new guidance, the adoption of ASU 2014-09 did not have a material impact on the Company’s consolidated financial position, results of operations, equity or cash flows. Recently Adopted Accounting Standards In March 2016, the FASB issued ASU No. 2016-09, “Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting” (ASU 2016-09). ASU 2016-09 modifies several aspects of the accounting for share-based payment awards, including income tax consequences, and classification on the statement of cash flows. The Company early adopted ASU 2016-09 in the first quarter of 2016. The provisions of ASU 2016-09 related to the timing of when excess tax benefits are recognized, minimum statutory withholding requirements and forfeitures were adopted using a modified retrospective transition method by means of a cumulative-effect adjustment to equity as of January 1, 2016. The provisions of ASU 2016-09 related to the recognition of excess tax benefits in the income statement and classification in the statement of cash flows were adopted prospectively and the prior periods were not retrospectively adjusted. The adoption of ASU 2016-09 did not materially impact the Company’s consolidated financial position, results of operations, equity or cash flows. In November 2015, the FASB issued ASU No. 2015-17, “Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes” (ASU 2015-17). ASU 2015-17 requires entities to present deferred tax assets and deferred tax liabilities as noncurrent on the balance sheet. Prior to the issuance of ASU 2015-17, deferred taxes were required to be presented as a net current asset or liability and a net noncurrent asset or liability. The Company adopted ASU 2015-17 on a prospective basis in the first quarter of 2016 and the prior period was not retrospectively adjusted. The adoption of ASU 2015-17 did not impact the Company’s consolidated financial position, results of operations, equity or cash flows. In May 2015, the FASB issued ASU No. 2015-09, “Financial Services - Insurance (Topic 944): Disclosures about Short-Duration Contracts” (ASU 2015-09). ASU 2015-09 requires insurance entities to provide additional disclosures about short-duration insurance liabilities, including incurred and paid medical costs information by year. The Company adopted the disclosure requirements of ASU 2015-09 and has included the new disclosures within Notes 2 and 7 . In April 2015, the FASB issued ASU No. 2015-03, “Interest-Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs” (ASU 2015-03). ASU 2015-03 requires debt issuance costs to be presented as a reduction of the carrying amount of the related debt liability. Prior to the issuance of ASU 2015-03, debt issuance costs were required to be presented as an asset on the balance sheet. The Company adopted ASU 2015-03 on a retrospective basis, as required, in the first quarter of 2016. The Company reclassified $129 million and $82 million in debt issuance costs that were recorded in other assets to long-term debt, less current maturities on the Consolidated Balance Sheet as of December 31, 2015 and 2014, respectively. The Company has determined that there have been no other recently adopted or issued accounting standards that had, or will have, a material impact on its Consolidated Financial Statements.

Fair Value Fair Value (Policies

Fair Value Fair Value (Policies)	12 Months Ended
	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurement, Policy [Policy Text Block]	Certain assets and liabilities are measured at fair value in the Consolidated Financial Statements or have fair values disclosed in the Notes to the Consolidated Financial Statements. These assets and liabilities are classified into one of three levels of a hierarchy defined by GAAP. In instances in which the inputs used to measure fair value fall into different levels of the fair value hierarchy, the fair value measurement is categorized in its entirety based on the lowest level input that is significant to the fair value measurement in its entirety. The Company’s assessment of the significance of a particular item to the fair value measurement in its entirety requires judgment, including the consideration of inputs specific to the asset or liability. The fair value hierarchy is summarized as follows: Level 1 — Quoted prices (unadjusted) for identical assets/liabilities in active markets. Level 2 — Other observable inputs, either directly or indirectly, including: • Quoted prices for similar assets/liabilities in active markets; • Quoted prices for identical or similar assets/liabilities in inactive markets (e.g., few transactions, limited information, noncurrent prices, high variability over time); • Inputs other than quoted prices that are observable for the asset/liability (e.g., interest rates, yield curves, implied volatilities, credit spreads); and • Inputs that are corroborated by other observable market data. Level 3 — Unobservable inputs that cannot be corroborated by observable market data. Transfers between levels, if any, are recorded as of the beginning of the reporting period in which the transfer occurs; there was no transfer between Levels 1, 2 or 3 of any financial assets or liabilities during the years ended December 31, 2016 or 2015 . Nonfinancial assets and liabilities or financial assets and liabilities that are measured at fair value on a nonrecurring basis are subject to fair value adjustments only in certain circumstances, such as when the Company records an impairment. There were no significant fair value adjustments for these assets and liabilities recorded during the years ended December 31, 2016 or 2015 . The following methods and assumptions were used to estimate the fair value and determine the fair value hierarchy classification of each class of financial instrument included in the tables below: Cash and Cash Equivalents. The carrying value of cash and cash equivalents approximates fair value as maturities are less than three months. Fair values of cash equivalent instruments that do not trade on a regular basis in active markets are classified as Level 2. Debt and Equity Securities. Fair values of debt and equity securities are based on quoted market prices, where available. The Company obtains one price for each security primarily from a third-party pricing service (pricing service), which generally uses quoted or other observable inputs for the determination of fair value. The pricing service normally derives the security prices through recently reported trades for identical or similar securities, and, if necessary, makes adjustments through the reporting date based upon available observable market information. For securities not actively traded, the pricing service may use quoted market prices of comparable instruments or discounted cash flow analyses, incorporating inputs that are currently observable in the markets for similar securities. Inputs that are often used in the valuation methodologies include, but are not limited to, benchmark yields, credit spreads, default rates, prepayment speeds and nonbinding broker quotes. As the Company is responsible for the determination of fair value, it performs quarterly analyses on the prices received from the pricing service to determine whether the prices are reasonable estimates of fair value. Specifically, the Company compares the prices received from the pricing service to prices reported by a secondary pricing source, such as its custodian, its investment consultant and third-party investment advisors. Additionally, the Company compares changes in the reported market values and returns to relevant market indices to test the reasonableness of the reported prices. The Company’s internal price verification procedures and reviews of fair value methodology documentation provided by independent pricing services have not historically resulted in adjustment in the prices obtained from the pricing service. Fair values of debt securities that do not trade on a regular basis in active markets but are priced using other observable inputs are classified as Level 2. Fair value estimates for Level 1 and Level 2 equity securities are based on quoted market prices for actively traded equity securities and/or other market data for the same or comparable instruments and transactions in establishing the prices. The fair values of Level 3 investments in venture capital portfolios are estimated using a market valuation technique that relies heavily on management assumptions and qualitative observations. Under the market approach, the fair values of the Company’s various venture capital investments are computed using limited quantitative and qualitative observations of activity for similar companies in the current market. The Company’s market modeling utilizes, as applicable, transactions for comparable companies in similar industries that also have similar revenue and growth characteristics and preferences in their capital structure. Key significant unobservable inputs in the market technique include implied earnings before interest, taxes, depreciation and amortization (EBITDA) multiples and revenue multiples. Additionally, the fair values of certain of the Company’s venture capital securities are based on recent transactions in inactive markets for identical or similar securities. Significant changes in any of these inputs could result in significantly lower or higher fair value measurements. Throughout the procedures discussed above in relation to the Company’s processes for validating third-party pricing information, the Company validates the understanding of assumptions and inputs used in security pricing and determines the proper classification in the hierarchy based on that understanding. Assets Under Management. Assets under management consists of debt securities and other investments held to fund costs associated with the AARP Program and are priced and classified using the same methodologies as the Company’s investments in debt and equity securities. Other Assets. The fair values of the Company’s other assets are estimated and classified using the same methodologies as the Company’s investments in debt securities. Interest Rate Swaps. Fair values of the Company’s swaps are estimated using the terms of the swaps and publicly available information, including market yield curves. Because the swaps are unique and not actively traded but are valued using other observable inputs, the fair values are classified as Level 2. Long-Term Debt. The fair values of the Company’s long-term debt are estimated and classified using the same methodologies as the Company’s investments in debt securities.

Schedule I (Policies)

Schedule I (Policies)	12 Months Ended
	Dec. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Basis of Presentation and Significant Accounting Policies [Text Block]	Basis of Presentation, Use of Estimates and Significant Accounting Policies Basis of Presentation The Company has prepared the Consolidated Financial Statements according to U.S. Generally Accepted Accounting Principles (GAAP) and has included the accounts of UnitedHealth Group and its subsidiaries. Use of Estimates These Consolidated Financial Statements include certain amounts based on the Company’s best estimates and judgments. The Company’s most significant estimates relate to estimates and judgments for medical costs payable and revenues, valuation and impairment analysis of goodwill and other intangible assets, estimates of other current liabilities and other current receivables and valuations of certain investments. Certain of these estimates require the application of complex assumptions and judgments, often because they involve matters that are inherently uncertain and will likely change in subsequent periods. The impact of any change in estimates is included in earnings in the period in which the estimate is adjusted. Revenues Premiums Premium revenues are primarily derived from risk-based health insurance arrangements in which the premium is typically at a fixed rate per individual served for a one-year period, and the Company assumes the economic risk of funding its customers’ health care and related administrative costs. Premium revenues are recognized in the period in which eligible individuals are entitled to receive health care benefits. Health care premium payments received from the Company’s customers in advance of the service period are recorded as unearned revenues. Fully insured commercial products of U.S. health plans, Medicare Advantage and Medicare Prescription Drug Benefit (Medicare Part D) plans with medical loss ratios as calculated under the definitions in the Patient Protection and Affordable Care Act (ACA) and related federal and state regulations and implementing regulations, that fall below certain targets are required to rebate ratable portions of their premiums annually. Medicare Advantage premium revenue includes the impact of Centers for Medicare & Medicaid Services (CMS) quality bonuses based on plans’ Star ratings. Premium revenues are recognized based on the estimated premiums earned net of projected rebates because the Company is able to reasonably estimate the ultimate premiums of these contracts. The Company also records premium revenues from capitation arrangements at its OptumHealth businesses. The Company’s Medicare Advantage and Medicare Part D premium revenues are subject to periodic adjustment under CMS’ risk adjustment payment methodology. CMS deploys a risk adjustment model that apportions premiums paid to all health plans according to health severity and certain demographic factors. The CMS risk adjustment model provides higher per member payments for enrollees diagnosed with certain conditions and lower payments for enrollees who are healthier. Under this risk adjustment methodology, CMS calculates the risk adjusted premium payment using diagnosis data from hospital inpatient, hospital outpatient and physician treatment settings. The Company and health care providers collect, capture and submit the necessary and available diagnosis data to CMS within prescribed deadlines. The Company estimates risk adjustment revenues based upon the diagnosis data submitted and expected to be submitted to CMS. Risk adjustment data for certain of the Company’s plans are subject to review by the government, including audit by regulators. See Note 12 for additional information regarding these audits. Products and Services For the Company’s OptumRx pharmacy care services business, the majority of revenues are derived from products sold through a contracted network of retail pharmacies or home delivery and specialty pharmacy facilities. Product revenues include ingredient costs (net of rebates), a negotiated dispensing fee and customer co-payments for drugs dispensed through the Company’s mail-service pharmacy. In retail pharmacy transactions, revenues recognized exclude the member’s applicable co-payment. Pharmacy products are billed to customers based on the number of transactions occurring during the billing period. Product revenues are recognized when the prescriptions are dispensed through the retail network or received by consumers through the Company’s mail-service pharmacy. The Company has entered into contracts in which it is primarily obligated to pay its network pharmacy providers for benefits provided to their customers regardless of whether the Company is paid. The Company is also involved in establishing the prices charged by retail pharmacies, determining which drugs will be included in formulary listings and selecting which retail pharmacies will be included in the network offered to plan sponsors’ members. As a result, revenues are reported on a gross basis. Services revenue consists of fees derived from services performed for customers that self-insure the health care costs of their employees and employees’ dependents. Under service fee contracts, the Company receives monthly, a fixed fee per employee, which is recognized as revenue as the Company performs, or makes available the applicable services to the customer. The customers retain the risk of financing health care costs for their employees and employees’ dependents, and the Company administers the payment of customer funds to physicians and other health care professionals from customer-funded bank accounts. As the Company has neither the obligation for funding the health care costs, nor the primary responsibility for providing the medical care, the Company does not recognize premium revenue and medical costs for these contracts in its Consolidated Financial Statements. For these fee-based customer arrangements, the Company provides coordination and facilitation of medical services; transaction processing; customer, consumer and care professional services; and access to contracted networks of physicians, hospitals and other health care professionals. These services are performed throughout the contract period. Revenues are also comprised of a number of services and products sold through Optum. For its financial services offerings, OptumHealth charges fees and earns investment income on managed funds. OptumInsight provides software and information products, advisory consulting arrangements and services outsourcing contracts, which may be delivered over several years. OptumInsight revenues are generally recognized over time on either a time and materials basis, or ratably as services are performed or made available to customers. Medical Costs and Medical Costs Payable The Company’s estimate of medical costs payable represents management’s best estimate of its liability for unpaid medical costs as of December 31, 2016. Each period, the Company re-examines previously established medical costs payable estimates based on actual claim submissions and other changes in facts and circumstances. As more complete claim information becomes available, the Company adjusts the amount of the estimates and includes the changes in estimates in medical costs in the period in which the change is identified. Approximately 90% of claims related to medical care services are known and settled within 90 days from the date of service and substantially all within twelve months. Medical costs and medical costs payable include estimates of the Company’s obligations for medical care services that have been rendered on behalf of insured consumers, but for which claims have either not yet been received, processed, or paid. The Company develops estimates for medical care services incurred but not reported (IBNR), which includes estimates for claims that have not been received or fully processed, using an actuarial process that is consistently applied, centrally controlled and automated. The actuarial models consider factors such as time from date of service to claim processing, seasonal variances in medical care consumption, health care professional contract rate changes, medical care utilization and other medical cost trends, membership volume and demographics, the introduction of new technologies, benefit plan changes, and business mix changes related to products, customers and geography. In developing its medical costs payable estimates, the Company applies different estimation methods depending on which incurred claims are being estimated. For the most recent two months, the Company estimates claim costs incurred by applying observed medical cost trend factors to the average per member per month (PMPM) medical costs incurred in prior months for which more complete claim data are available, supplemented by a review of near-term completion factors (actuarial estimates, based upon historical experience and analysis of current trends, of the percentage of incurred claims during a given period that have been adjudicated by the Company at the date of estimation). For months prior to the most recent two months, the Company applies the completion factors to actual claims adjudicated-to-date to estimate the expected amount of ultimate incurred claims for those months. Cost of Products Sold The Company’s cost of products sold includes the cost of pharmaceuticals dispensed to unaffiliated customers either directly at its mail and specialty pharmacy locations, or indirectly through its nationwide network of participating pharmacies. Rebates attributable to non-affiliated clients are accrued as rebates receivable and a reduction of cost of products sold with a corresponding payable for the amounts of the rebates to be remitted to those non-affiliated clients in accordance with their contracts and recorded in the Consolidated Statements of Operations as a reduction of product revenue. Cost of products sold also includes the cost of personnel to support the Company’s transaction processing services, system sales, maintenance and professional services. Cash, Cash Equivalents and Investments Cash and cash equivalents are highly liquid investments that have an original maturity of three months or less. The fair value of cash and cash equivalents approximates their carrying value because of the short maturity of the instruments. Investments with maturities of less than one year are classified as short-term. Because of regulatory requirements, certain investments are included in long-term investments regardless of their maturity date. The Company classifies these investments as held-to-maturity and reports them at amortized cost. Substantially all other investments are classified as available-for-sale and reported at fair value based on quoted market prices, where available. The Company excludes unrealized gains and losses on investments in available-for-sale securities from net earnings and reports them as comprehensive income and, net of income tax effects, as a separate component of equity. To calculate realized gains and losses on the sale of investments, the Company specifically identifies the cost of each investment sold. The Company evaluates an investment for impairment by considering the length of time and extent to which market value has been less than cost or amortized cost, the financial condition and near-term prospects of the issuer as well as specific events or circumstances that may influence the operations of the issuer and the Company’s intent to sell the security or the likelihood that it will be required to sell the security before recovery of the entire amortized cost. New information and the passage of time can change these judgments. The Company manages its investment portfolio to limit its exposure to any one issuer or market sector, and largely limits its investments to investment grade quality. Securities downgraded below policy minimums after purchase will be disposed of in accordance with the Company’s investment policy. Assets Under Management The Company provides health insurance products and services to members of AARP under a Supplemental Health Insurance Program (the AARP Program) and to AARP members and non-members under separate Medicare Advantage and Medicare Part D arrangements. The products and services under the AARP Program include supplemental Medicare benefits, hospital indemnity insurance, including insurance for individuals between 50 to 64 years of age and other related products. Pursuant to the Company’s agreement, AARP Program assets are managed separately from the Company’s general investment portfolio and are used to pay costs associated with the AARP Program. These assets are invested at the Company’s discretion, within investment guidelines approved by AARP. The Company does not guarantee any rates of return on these investments and, upon any transfer of the AARP Program contract to another entity, the Company would transfer cash equal in amount to the fair value of these investments at the date of transfer to that entity. Because the purpose of these assets is to fund the medical costs payable, the rate stabilization fund (RSF) liabilities and other related liabilities associated with this AARP contract, assets under management are classified as current assets, consistent with the classification of these liabilities. The effects of changes in other balance sheet amounts associated with the AARP Program also accrue to the overall benefit of the AARP policyholders through the RSF balance. Accordingly, the Company excludes the effect of such changes in its Consolidated Statements of Cash Flows. Other Current Receivables Other current receivables include amounts due from pharmaceutical manufacturers for rebates and Medicare Part D drug discounts and other miscellaneous amounts due to the Company. The Company’s pharmacy care services businesses contract with pharmaceutical manufacturers, some of which provide rebates based on use of the manufacturers’ products by its affiliated and non-affiliated clients. The Company accrues rebates as they are earned by its clients on a monthly basis based on the terms of the applicable contracts, historical data and current estimates. The pharmacy care services businesses bill these rebates to the manufacturers on a monthly or quarterly basis depending on the contractual terms and records rebates attributable to affiliated clients as a reduction to medical costs. The Company generally receives rebates from two to five months after billing. As of December 31, 2016 and 2015, total pharmaceutical manufacturer rebates receivable included in other receivables in the Consolidated Balance Sheets amounted to $ 3.3 billion and $2.6 billion , respectively. For details on the Company’s Medicare Part D receivables see “Medicare Part D Pharmacy Benefits” below. Medicare Part D Pharmacy Benefits The Company serves as a plan sponsor offering Medicare Part D prescription drug insurance coverage under contracts with CMS. Under the Medicare Part D program, there are seven separate elements of payment received by the Company during the plan year. These payment elements are as follows: • CMS Premium. CMS pays a fixed monthly premium per member to the Company for the entire plan year. • Member Premium. Additionally, certain members pay a fixed monthly premium to the Company for the entire plan year. • Low-Income Premium Subsidy. For qualifying low-income members, CMS pays some or all of the member’s monthly premiums to the Company on the member’s behalf. • Catastrophic Reinsurance Subsidy . CMS pays the Company a cost reimbursement estimate monthly to fund the CMS obligation to pay approximately 80% of the costs incurred by individual members in excess of the individual annual out-of-pocket maximum. A settlement is made with CMS based on actual cost experience, after the end of the plan year. • Low-Income Member Cost Sharing Subsidy. For qualifying low-income members, CMS pays on the member’s behalf some or all of a member’s cost sharing amounts, such as deductibles and coinsurance. The cost sharing subsidy is funded by CMS through monthly payments to the Company. The Company administers and pays the subsidized portion of the claims on behalf of CMS, and a settlement payment is made between CMS and the Company based on actual claims and premium experience, after the end of the plan year. • CMS Risk-Share. Premiums from CMS are subject to risk corridor provisions that compare costs targeted in the Company’s annual bids by product and region to actual prescription drug costs, limited to actual costs that would have been incurred under the standard coverage as defined by CMS. Variances of more than 5% above or below the original bid submitted by the Company may result in CMS making additional payments to the Company or require the Company to refund to CMS a portion of the premiums it received. The Company estimates and recognizes an adjustment to premium revenues related to the risk corridor payment settlement based upon pharmacy claims experience to date. The estimate of the settlement associated with these risk corridor provisions requires the Company to consider factors that may not be certain, including estimates of eligible pharmacy costs and member eligibility status differences with CMS. The Company records risk-share adjustments to premium revenues in the Consolidated Statements of Operations and other current liabilities or other current receivables in the Consolidated Balance Sheets. • Drug Discount. The ACA mandated a consumer discount on brand name prescription drugs for Medicare Part D plan participants in the coverage gap. This discount is funded by CMS and pharmaceutical manufacturers while the Company administers the application of these funds. Accordingly, amounts received are not reflected as premium revenues, but rather are accounted for as deposits. The Company records a liability when amounts are received from CMS and a receivable when the Company bills the pharmaceutical manufacturers. Related cash flows are presented as customer funds administered within financing activities in the Consolidated Statements of Cash Flows. The CMS Premium, the Member Premium and the Low-Income Premium Subsidy represent payments for the Company’s insurance risk coverage under the Medicare Part D program and, therefore, are recorded as premium revenues in the Consolidated Statements of Operations. Premium revenues are recognized ratably over the period in which eligible individuals are entitled to receive prescription drug benefits. The Company records premium payments received in advance of the applicable service period in unearned revenues in the Consolidated Balance Sheets. The Catastrophic Reinsurance Subsidy and the Low-Income Member Cost Sharing Subsidy (Subsidies) represent cost reimbursements under the Medicare Part D program. Amounts received for these Subsidies are not reflected as premium revenues, but rather are accounted for as receivables and/or deposits. Related cash flows are presented as customer funds administered within financing activities in the Consolidated Statements of Cash Flows. Pharmacy care costs and administrative costs under the contract are expensed as incurred and are recognized in medical costs and operating costs, respectively, in the Consolidated Statements of Operations. The final 2016 risk-share amount is expected to be settled during the second half of 2017, and is subject to the reconciliation process with CMS. The Consolidated Balance Sheets include the following amounts associated with the Medicare Part D program: December 31, 2016 December 31, 2015 (in millions) Subsidies Drug Discount Risk-Share Subsidies Drug Discount Risk-Share Other current receivables $ 934 $ 543 $ — $ 1,703 $ 423 $ — Other current liabilities — 267 471 — 58 496 Property, Equipment and Capitalized Software Property, equipment and capitalized software are stated at cost, net of accumulated depreciation and amortization. Capitalized software consists of certain costs incurred in the development of internal-use software, including external direct costs of materials and services and applicable payroll costs of employees devoted to specific software development. The Company calculates depreciation and amortization using the straight-line method over the estimated useful lives of the assets. The useful lives for property, equipment and capitalized software are: Furniture, fixtures and equipment 3 to 7 years Buildings 35 to 40 years Capitalized software 3 to 5 years Leasehold improvements are depreciated over the shorter of the remaining lease term or their estimated useful economic life. Goodwill To determine whether goodwill is impaired, annually or more frequently if needed, the Company performs a multi-step impairment test. The Company may first assess qualitative factors to determine if it is more likely than not that the carrying value of a reporting unit exceeds its estimated fair value. The Company may also elect to skip the qualitative testing and proceed directly to the quantitative testing. When performing quantitative testing, the Company first estimates the fair values of its reporting units using discounted cash flows. To determine fair values, the Company must make assumptions about a wide variety of internal and external factors. Significant assumptions used in the impairment analysis include financial projections of free cash flow (including significant assumptions about operations, capital requirements and income taxes), long-term growth rates for determining terminal value and discount rates. Comparative market multiples are used to corroborate the results of the discounted cash flow test. If the fair value is less than the carrying value of the reporting unit, then the implied value of goodwill would be calculated and compared to the carrying amount of goodwill to determine whether goodwill is impaired. There was no impairment of goodwill during the year ended December 31, 2016 . Intangible Assets The Company’s intangible assets are subject to impairment tests when events or circumstances indicate that an intangible asset (or asset group) may be impaired. The Company’s indefinite lived intangible assets are also tested for impairment annually. There was no impairment of intangible assets during the year ended December 31, 2016 . Accounts Payable and Accrued Liabilities The Company had checks outstanding of $1.5 billion and $1.6 billion as of December 31, 2016 and 2015, respectively, which were classified as accounts payable and accrued liabilities and the change in this balance has been reflected within other financing activities in the Consolidated Statements of Cash Flows. Other Current Liabilities Other current liabilities include health savings account deposits ( $5.7 billion and $3.6 billion as of December 31, 2016 and 2015 , respectively), the RSF associated with the AARP Program, deposits under the Medicare Part D program (see “Medicare Part D Pharmacy Benefits” above), accruals for premium rebate payments under the ACA, the current portion of future policy benefits and customer balances. Future Policy Benefits Future policy benefits represent account balances that accrue to the benefit of the policyholders, excluding surrender charges, for universal life and investment annuity products and for long-duration health policies sold to individuals for which some of the premium received in the earlier years is intended to pay benefits to be incurred in future years. Policy Acquisition Costs The Company’s short duration health insurance contracts typically have a one-year term and may be canceled by the customer with at least 30 days’ notice. Costs related to the acquisition and renewal of short duration customer contracts are charged to expense as incurred. Redeemable Noncontrolling Interests Redeemable noncontrolling interests in the Company’s subsidiaries whose redemption is outside the control of the Company are classified as temporary equity. The following table provides details of the Company's redeemable noncontrolling interests’ activity for the years ended December 31, 2016 and 2015 : (in millions) 2016 2015 Redeemable noncontrolling interests, beginning of period $ 1,736 $ 1,388 Net earnings 16 29 Acquisitions 34 196 Redemptions (123 ) (116 ) Distributions (11 ) (19 ) Fair value and other adjustments 360 258 Redeemable noncontrolling interests, end of period $ 2,012 $ 1,736 Share-Based Compensation The Company recognizes compensation expense for share-based awards, including stock options, stock-settled stock appreciation rights (SARs) and restricted stock and restricted stock units (collectively, restricted shares), on a straight-line basis over the related service period (generally the vesting period) of the award, or to an employee’s eligible retirement date under the award agreement, if earlier. Restricted shares vest ratably; primarily over two to five years and compensation expense related to restricted shares is based on the share price on date of grant. Stock options and SARs vest ratably primarily over four years and may be exercised up to 10 years from the date of grant. Compensation expense related to stock options and SARs is based on the fair value at date of grant, which is estimated on the date of grant using a binomial option-pricing model. Under the Company’s Employee Stock Purchase Plan (ESPP) eligible employees are allowed to purchase the Company’s stock at a discounted price, which is 85% of the lower market price of the Company’s common stock at the beginning or at the end of the six-month purchase period. Share-based compensation expense for all programs is recognized in operating costs in the Consolidated Statements of Operations. Net Earnings Per Common Share The Company computes basic earnings per common share attributable to UnitedHealth Group common shareholders by dividing net earnings attributable to UnitedHealth Group common shareholders by the weighted-average number of common shares outstanding during the period. The Company determines diluted net earnings per common share attributable to UnitedHealth Group common shareholders using the weighted-average number of common shares outstanding during the period, adjusted for potentially dilutive shares associated with stock options, SARs, restricted shares and the ESPP, (collectively, common stock equivalents) using the treasury stock method. The treasury stock method assumes a hypothetical issuance of shares to settle the share-based awards, with the assumed proceeds used to purchase common stock at the average market price for the period. Assumed proceeds include the amount the employee must pay upon exercise and any unrecognized compensation cost. The difference between the number of shares assumed issued and number of shares assumed purchased represents the dilutive shares. Health Insurance Industry Tax The ACA includes an annual, nondeductible insurance industry tax (Health Insurance Industry Tax) to be levied proportionally across the insurance industry for risk-based health insurance products. The Company estimates its liability for the Health Insurance Industry Tax based on a ratio of the Company’s applicable net premiums written compared to the U.S. health insurance industry total applicable net premiums, both for the previous calendar year. The Company records in full the estimated liability for the Health Insurance Industry Tax at the beginning of the calendar year with a corresponding deferred cost that is amortized to operating costs on the Consolidated Statements of Operations using a straight-line method of allocation over the calendar year. The liability is recorded in accounts payable and accrued liabilities and the corresponding deferred cost is recorded in prepaid expenses and other current assets on the Consolidated Balance Sheets. A provision in the 2016 Federal Budget imposed a one year moratorium for 2017 on the collection of the Health Insurance Industry Tax. Premium Stabilization Programs The ACA included three programs designed to stabilize health insurance markets (Premium Stabilization Programs): a permanent risk adjustment program; a temporary risk corridors program; and a transitional reinsurance program (Reinsurance Program). The risk-adjustment provisions apply to market reform compliant individual and small group plans in the commercial markets. Under the program, each covered member is assigned a risk score based upon demographic information and applicable diagnostic codes from the current year paid claims, in order to determine an average risk score for each plan in a particular state and market risk pool. Generally, a plan with a risk score that is less than the state’s average risk score will pay into the pool, while a plan with a risk score that is greater than the state’s average will receive money from the pool. The temporary risk corridors provisions are intended to limit the gains and losses of individual and small group qualified health plans. Plans are required to calculate the U.S. Department of Health and Human Services (HHS) risk corridor ratio of allowable costs to the defined target amount. Qualified health plans with ratios below 97% are required to make payments to HHS, while plans with ratios greater than 103% expect to receive funds from HHS. The Reinsurance Program and temporary risk corridors program expired at the end of 2016. For the Premium Stabilization Programs, the Company records a receivable or payable as an adjustment to premium revenue based on year-to-date experience when the amounts are reasonably estimable and collection is reasonably assured. Final adjustments or recoverable amounts to the Premium Stabilization Programs are determined by HHS in the year following the policy year. Recently Issued Accounting Standards In February 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standard Update (ASU) No. 2016-02, “Leases (Topic 842)” (ASU 2016-02). Under ASU 2016-02, an entity will be required to recognize assets and liabilities for the rights and obligations created by leases on the entity’s balance sheet for both finance and operating leases. For leases with a term of 12 months or less, an entity can elect to not recognize lease assets and lease liabilities and expense the lease over a straight-line basis for the term of the lease. ASU 2016-02 will require new disclosures that depict the amount, timing, and uncertainty of cash flows pertaining to an entity’s leases. Companies are required to adopt the new standard using a modified retrospective approach for annual and interim periods beginning after December 15, 2018. Early adoption of ASU 2016-02 is permitted. When adopted, the Company does not expect ASU 2016-02 to have a material impact on its results of operations, equity or cash flows. The impact of ASU 2016-02 on the Company’s consolidated financial position will be based on leases outstanding at the time of adoption. In January 2016, the FASB issued ASU 2016-01, “Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities” (ASU 2016-01). The new guidance changes the current accounting related to (i) the classification and measurement of certain equity investments, (ii) the presentation of changes in the fair value of financial liabilities measured under the fair value option that are due to instrument-specific credit risk, and (iii) certain disclosures associated with the fair value of financial instruments. Most notably, ASU 2016-01 requires that equity investments, with certain exemptions, be measured at fair value with changes in fair value recognized in net income as opposed to other comprehensive income. The new guidance is effective for annual and interim reporting periods beginning after December 15, 2017. As of December 31, 2016, based on equity securities held, the Company does not expect ASU 2016-01 to have a material impact on its consolidated financial position, results of operations, equity or cash flows. The Company will continue to evaluate any changes in its mix of investments or market conditions and the related impact of ASU 2016-01. In May 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606)” (ASU 2014-09) as modified by ASU No. 2015-14, “Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date,” ASU 2016-08, “Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net),” ASU No. 2016-10, “Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing,” ASU No. 2016-12, “Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expe
Consolidation, Subsidiaries or Other Investments, Consolidated Entities, Policy [Policy Text Block]	Redeemable Noncontrolling Interests Redeemable noncontrolling interests in the Company’s subsidiaries whose redemption is outside the control of the Company are classified as temporary equity. The following table provides details of the Company's redeemable noncontrolling interests’ activity for the years ended December 31, 2016 and 2015 : (in millions) 2016 2015 Redeemable noncontrolling interests, beginning of period $ 1,736 $ 1,388 Net earnings 16 29 Acquisitions 34 196 Redemptions (123 ) (116 ) Distributions (11 ) (19 ) Fair value and other adjustments 360 258 Redeemable noncontrolling interests, end of period $ 2,012 $ 1,736
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Basis of Presentation and Significant Accounting Policies [Text Block]	Basis of Presentation UnitedHealth Group’s parent company financial information has been derived from its consolidated financial statements and should be read in conjunction with the consolidated financial statements included in this Form 10-K. The accounting policies for the registrant are the same as those described in Note 2 of Notes to the Consolidated Financial Statements included in Part II, Item 8, “Financial Statements.”
Consolidation, Subsidiaries or Other Investments, Consolidated Entities, Policy [Policy Text Block]	Subsidiary Transactions Investment in Subsidiaries. UnitedHealth Group’s investment in subsidiaries is stated at cost plus equity in undistributed earnings of subsidiaries.

Basis of Presentation, Uses o26

Basis of Presentation, Uses of Estimates and Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2016
Schedule of Other Current Receivables and Other Policy Liabilities Associated with Medicare Part D Program [Table Text Block]	The Consolidated Balance Sheets include the following amounts associated with the Medicare Part D program: December 31, 2016 December 31, 2015 (in millions) Subsidies Drug Discount Risk-Share Subsidies Drug Discount Risk-Share Other current receivables $ 934 $ 543 $ — $ 1,703 $ 423 $ — Other current liabilities — 267 471 — 58 496
Property, Plant and Equipment [Table Text Block]	A summary of property, equipment and capitalized software is as follows: (in millions) December 31, 2016 December 31, 2015 Land and improvements $ 324 $ 237 Buildings and improvements 3,148 2,420 Computer equipment 2,021 1,945 Furniture and fixtures 999 790 Less accumulated depreciation (2,621 ) (2,163 ) Property and equipment, net 3,871 3,229 Capitalized software 3,158 2,642 Less accumulated amortization (1,128 ) (1,010 ) Capitalized software, net 2,030 1,632 Total property, equipment and capitalized software, net $ 5,901 $ 4,861
Redeemable Noncontrolling Interest [Table Text Block]	The following table provides details of the Company's redeemable noncontrolling interests’ activity for the years ended December 31, 2016 and 2015 : (in millions) 2016 2015 Redeemable noncontrolling interests, beginning of period $ 1,736 $ 1,388 Net earnings 16 29 Acquisitions 34 196 Redemptions (123 ) (116 ) Distributions (11 ) (19 ) Fair value and other adjustments 360 258 Redeemable noncontrolling interests, end of period $ 2,012 $ 1,736
Useful Life [Member]
Property, Plant and Equipment [Table Text Block]	The Company calculates depreciation and amortization using the straight-line method over the estimated useful lives of the assets. The useful lives for property, equipment and capitalized software are: Furniture, fixtures and equipment 3 to 7 years Buildings 35 to 40 years Capitalized software 3 to 5 years

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2016
Short-Term and Long-Term Investments [Table Text Block]	A summary of short-term and long-term investments by major security type is as follows: (in millions) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value December 31, 2016 Debt securities - available-for-sale: U.S. government and agency obligations $ 2,294 $ 1 $ (31 ) $ 2,264 State and municipal obligations 7,120 40 (101 ) 7,059 Corporate obligations 10,944 41 (58 ) 10,927 U.S. agency mortgage-backed securities 2,963 7 (43 ) 2,927 Non-U.S. agency mortgage-backed securities 1,009 3 (10 ) 1,002 Total debt securities - available-for-sale 24,330 92 (243 ) 24,179 Equity securities 2,036 52 (47 ) 2,041 Debt securities - held-to-maturity: U.S. government and agency obligations 250 1 — 251 State and municipal obligations 5 — — 5 Corporate obligations 238 — — 238 Total debt securities - held-to-maturity 493 1 — 494 Total investments $ 26,859 $ 145 $ (290 ) $ 26,714 December 31, 2015 Debt securities - available-for-sale: U.S. government and agency obligations $ 1,982 $ 1 $ (6 ) $ 1,977 State and municipal obligations 6,022 149 (3 ) 6,168 Corporate obligations 7,446 41 (81 ) 7,406 U.S. agency mortgage-backed securities 2,127 13 (16 ) 2,124 Non-U.S. agency mortgage-backed securities 962 5 (11 ) 956 Total debt securities - available-for-sale 18,539 209 (117 ) 18,631 Equity securities 1,638 58 (57 ) 1,639 Debt securities - held-to-maturity: U.S. government and agency obligations 163 1 — 164 State and municipal obligations 8 — — 8 Corporate obligations 339 — — 339 Total debt securities - held-to-maturity 510 1 — 511 Total investments $ 20,687 $ 268 $ (174 ) $ 20,781
Investments by Contractual Maturity [Table Text Block]	The amortized cost and fair value of debt securities as of December 31, 2016 , by contractual maturity, were as follows: Available-for-Sale Held-to-Maturity (in millions) Amortized Cost Fair Value Amortized Fair Due in one year or less $ 2,893 $ 2,895 $ 151 $ 151 Due after one year through five years 9,646 9,625 153 153 Due after five years through ten years 5,706 5,645 124 124 Due after ten years 2,113 2,085 65 66 U.S. agency mortgage-backed securities 2,963 2,927 — — Non-U.S. agency mortgage-backed securities 1,009 1,002 — — Total debt securities $ 24,330 $ 24,179 $ 493 $ 494
Fair Value of Available-for-Sale Investments with Gross Unrealized Losses by Investment Type and Length of Time that Individual Securities have been in a Continuous Unrealized Loss Position [Table Text Block]	The fair value of available-for-sale investments with gross unrealized losses by major security type and length of time that individual securities have been in a continuous unrealized loss position were as follows: Less Than 12 Months 12 Months or Greater Total (in millions) Fair Value Gross Unrealized Losses Fair Value Gross Fair Value Gross December 31, 2016 Debt securities - available-for-sale: U.S. government and agency obligations $ 1,794 $ (31 ) $ — $ — $ 1,794 $ (31 ) State and municipal obligations 4,376 (101 ) — — 4,376 (101 ) Corporate obligations 5,128 (56 ) 137 (2 ) 5,265 (58 ) U.S. agency mortgage-backed securities 2,247 (40 ) 79 (3 ) 2,326 (43 ) Non-U.S. agency mortgage-backed securities 544 (7 ) 97 (3 ) 641 (10 ) Total debt securities - available-for-sale $ 14,089 $ (235 ) $ 313 $ (8 ) $ 14,402 $ (243 ) Equity securities $ 93 $ (5 ) $ 91 $ (42 ) $ 184 $ (47 ) December 31, 2015 Debt securities - available-for-sale: U.S. government and agency obligations $ 1,473 $ (6 ) $ — $ — $ 1,473 $ (6 ) State and municipal obligations 650 (3 ) — — 650 (3 ) Corporate obligations 4,629 (63 ) 339 (18 ) 4,968 (81 ) U.S. agency mortgage-backed securities 1,304 (12 ) 116 (4 ) 1,420 (16 ) Non-U.S. agency mortgage-backed securities 593 (7 ) 127 (4 ) 720 (11 ) Total debt securities - available-for-sale $ 8,649 $ (91 ) $ 582 $ (26 ) $ 9,231 $ (117 ) Equity securities $ 112 $ (11 ) $ 89 $ (46 ) $ 201 $ (57 )
Net Realized Gains, Included in Investment and Other Income [Table Text Block]	Net realized gains reclassified out of accumulated other comprehensive income were from the following sources: For the Years Ended December 31, (in millions) 2016 2015 2014 Total other-than-temporary impairment recognized in earnings $ (45 ) $ (22 ) $ (26 ) Gross realized losses from sales (44 ) (28 ) (47 ) Gross realized gains from sales 255 191 284 Net realized gains (included in investment and other income on the Consolidated Statements of Operations) 166 141 211 Income tax effect (included in provision for income taxes on the Consolidated Statements of Operations) (60 ) (53 ) (77 ) Realized gains, net of taxes $ 106 $ 88 $ 134

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets and Liabilities, Measured at Fair Value Recurring Basis [Table Text Block]	The following table presents a summary of fair value measurements by level and carrying values for items measured at fair value on a recurring basis in the Consolidated Balance Sheets: (in millions) Quoted Prices in Active Markets (Level 1) Other Observable Inputs (Level 2) Unobservable Inputs (Level 3) Total Fair and Carrying Value December 31, 2016 Cash and cash equivalents $ 10,386 $ 44 $ — $ 10,430 Debt securities - available-for-sale: U.S. government and agency obligations 2,017 247 — 2,264 State and municipal obligations — 7,059 — 7,059 Corporate obligations 21 10,804 102 10,927 U.S. agency mortgage-backed securities — 2,927 — 2,927 Non-U.S. agency mortgage-backed securities — 1,002 — 1,002 Total debt securities - available-for-sale 2,038 22,039 102 24,179 Equity securities 1,591 13 437 2,041 Assets under management 1,064 2,041 — 3,105 Interest rate swap assets — 55 — 55 Total assets at fair value $ 15,079 $ 24,192 $ 539 $ 39,810 Percentage of total assets at fair value 38 % 61 % 1 % 100 % Interest rate swap liabilities $ — $ 14 $ — $ 14 December 31, 2015 Cash and cash equivalents $ 10,906 $ 17 $ — $ 10,923 Debt securities - available-for-sale: U.S. government and agency obligations 1,779 198 — 1,977 State and municipal obligations — 6,168 — 6,168 Corporate obligations 5 7,308 93 7,406 U.S. agency mortgage-backed securities — 2,124 — 2,124 Non-U.S. agency mortgage-backed securities — 951 5 956 Total debt securities - available-for-sale 1,784 16,749 98 18,631 Equity securities 1,223 14 402 1,639 Assets under management 832 2,166 — 2,998 Interest rate swap assets — 93 — 93 Total assets at fair value $ 14,745 $ 19,039 $ 500 $ 34,284 Percentage of total assets at fair value 43 % 56 % 1 % 100 % Interest rate swap liabilities $ — $ 11 $ — $ 11
Fair Value Measurements, Nonrecurring [Table Text Block]	The following table presents a summary of fair value measurements by level and carrying values for certain financial instruments not measured at fair value on a recurring basis in the Consolidated Balance Sheets: (in millions) Quoted Prices in Active Markets (Level 1) Other Observable Inputs (Level 2) Unobservable Inputs (Level 3) Total Fair Value Total Carrying Value December 31, 2016 Debt securities - held-to-maturity: U.S. government and agency obligations $ 251 $ — $ — $ 251 $ 250 State and municipal obligations — — 5 5 5 Corporate obligations 20 8 210 238 238 Total debt securities - held-to-maturity $ 271 $ 8 $ 215 $ 494 $ 493 Other assets $ — $ 476 $ — $ 476 $ 471 Long-term debt and other financing obligations $ — $ 31,295 $ — $ 31,295 $ 29,337 December 31, 2015 Debt securities - held-to-maturity: U.S. government and agency obligations $ 164 $ — $ — $ 164 $ 163 State and municipal obligations — — 8 8 8 Corporate obligations 91 10 238 339 339 Total debt securities - held-to-maturity $ 255 $ 10 $ 246 $ 511 $ 510 Other assets $ — $ 493 $ — $ 493 $ 500 Long-term debt and other financing obligations $ — $ 29,455 $ — $ 29,455 $ 27,978
Reconciliation of Assets Measured at Fair Value on a Recurring Basis Using Level 3 Inputs [Table Text Block]	A reconciliation of the beginning and ending balances of assets measured at fair value on a recurring basis using Level 3 inputs is as follows: December 31, 2016 December 31, 2015 December 31, 2014 (in millions) Debt Securities Equity Securities Total Debt Securities Equity Securities Total Debt Securities Equity Securities Total Balance at beginning of period $ 98 $ 402 $ 500 $ 74 $ 310 $ 384 $ 42 $ 269 $ 311 Purchases 12 100 112 27 106 133 32 105 137 Sales (9 ) (29 ) (38 ) (4 ) (24 ) (28 ) (1 ) (180 ) (181 ) Net unrealized gains (losses) in accumulated other comprehensive income 1 (13 ) (12 ) 2 5 7 1 6 7 Net realized (losses) gains in investment and other income — (23 ) (23 ) (1 ) 5 4 — 110 110 Balance at end of period $ 102 $ 437 $ 539 $ 98 $ 402 $ 500 $ 74 $ 310 $ 384
Fair Value Inputs, Assets, Quantitative Information [Table Text Block]	The following table presents quantitative information regarding unobservable inputs that were significant to the valuation of assets measured at fair value on a recurring basis using Level 3 inputs: Range (in millions) Fair Value Valuation Technique Unobservable Input Low High December 31, 2016 Equity securities: Venture capital portfolios $ 404 Market approach - comparable companies Revenue multiple 1.0 6.0 EBITDA multiple 8.0 12.0 33 Market approach - recent transactions Inactive market transactions N/A N/A Total equity securities $ 437

Property, Plant, and Capitali29

Property, Plant, and Capitalized Software (Tables)	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment [Table Text Block]	A summary of property, equipment and capitalized software is as follows: (in millions) December 31, 2016 December 31, 2015 Land and improvements $ 324 $ 237 Buildings and improvements 3,148 2,420 Computer equipment 2,021 1,945 Furniture and fixtures 999 790 Less accumulated depreciation (2,621 ) (2,163 ) Property and equipment, net 3,871 3,229 Capitalized software 3,158 2,642 Less accumulated amortization (1,128 ) (1,010 ) Capitalized software, net 2,030 1,632 Total property, equipment and capitalized software, net $ 5,901 $ 4,861

Goodwill and Intangible Asset30

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2016
Goodwill [Line Items]
Schedule of Goodwill [Table Text Block]	Changes in the carrying amount of goodwill, by reportable segment, were as follows: (in millions) UnitedHealthcare OptumHealth OptumInsight OptumRx Consolidated Balance at January 1, 2015 $ 24,030 $ 3,834 $ 4,236 $ 840 $ 32,940 Acquisitions 128 1,817 89 10,732 12,766 Foreign currency effects and adjustments, net (1,233 ) 9 (29 ) — (1,253 ) Balance at December 31, 2015 22,925 5,660 4,296 11,572 44,453 Acquisitions 526 683 — 1,387 2,596 Foreign currency effects and adjustments, net 403 (21 ) 153 — 535 Balance at December 31, 2016 $ 23,854 $ 6,322 $ 4,449 $ 12,959 $ 47,584
Schedule of Acquired Finite-Lived Intangible Assets by Major Class [Table Text Block]	The gross carrying value, accumulated amortization and net carrying value of other intangible assets were as follows: December 31, 2016 December 31, 2015 (in millions) Gross Carrying Value Accumulated Amortization Net Carrying Value Gross Carrying Value Accumulated Amortization Net Carrying Value Customer-related $ 10,942 $ (3,416 ) $ 7,526 $ 10,270 $ (2,796 ) $ 7,474 Trademarks and technology 720 (323 ) 397 682 (249 ) 433 Trademarks - indefinite-lived 468 — 468 358 — 358 Other 258 (108 ) 150 209 (83 ) 126 Total $ 12,388 $ (3,847 ) $ 8,541 $ 11,519 $ (3,128 ) $ 8,391
Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table Text Block]	The acquisition date fair values and weighted-average useful lives assigned to finite-lived intangible assets acquired in business combinations consisted of the following by year of acquisition: 2016 2015 (in millions, except years) Fair Value Weighted-Average Useful Life Fair Value Weighted-Average Useful Life Customer-related $ 785 17 years $ 5,518 19 years Trademarks and technology 82 4 years 194 4 years Other 22 5 years — Total acquired finite-lived intangible assets $ 889 16 years $ 5,712 19 years
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]	Estimated full year amortization expense relating to intangible assets for each of the next five years ending December 31 is as follows: (in millions) 2017 $ 865 2018 755 2019 679 2020 596 2021 536

Medical Costs Payable (Tables)

Medical Costs Payable (Tables)	12 Months Ended
	Dec. 31, 2016
Insurance [Abstract]
Schedule of Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block]	The following table shows the components of the change in medical costs payable for the years ended December 31: (in millions) 2016 2015 2014 Medical costs payable, beginning of period $ 14,330 $ 12,040 $ 11,575 Reported medical costs: Current year 117,258 104,195 94,053 Prior years (220 ) (320 ) (420 ) Total reported medical costs 117,038 103,875 93,633 Medical payments: Payments for current year (101,696 ) (90,630 ) (82,750 ) Payments for prior years (13,281 ) (10,955 ) (10,418 ) Total medical payments (114,977 ) (101,585 ) (93,168 ) Medical costs payable, end of period $ 16,391 $ 14,330 $ 12,040
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Table Text Block]	The following is information about incurred and paid medical cost development as of December 31, 2016 : Net Incurred Medical Costs (in millions) For the Years ended December 31, Year 2015 2016 2015 $ 104,195 $ 103,973 2016 117,258 Total $ 221,231 Net Cumulative Medical Payments (in millions) For the Years ended December 31, Year 2015 2016 2015 $ (90,630 ) $ (103,885 ) 2016 (101,696 ) Total (205,581 ) Net remaining outstanding liabilities prior to 2015 741 Total medical costs payable $ 16,391

Commercial Paper and Long-Ter32

Commercial Paper and Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Instrument [Line Items]
Commercial Paper and Long-Term Debt [Table Text Block]	Commercial paper, term loan and senior unsecured long-term debt consisted of the following: December 31, 2016 December 31, 2015 (in millions, except percentages) Par Value Carrying Value Fair Value Par Value Carrying Value (a) Fair Value Commercial paper $ 3,633 $ 3,633 $ 3,633 $ 3,987 $ 3,987 $ 3,987 Floating rate term loan due July 2016 — — — 1,500 1,500 1,500 5.375% notes due March 2016 — — — 601 605 606 1.875% notes due November 2016 — — — 400 400 403 5.360% notes due November 2016 — — — 95 95 98 Floating rate notes due January 2017 750 750 750 750 749 751 6.000% notes due June 2017 441 446 450 441 458 469 1.450% notes due July 2017 750 750 751 750 749 750 1.400% notes due October 2017 625 624 626 625 624 624 6.000% notes due November 2017 156 159 163 156 162 168 1.400% notes due December 2017 750 751 750 750 751 748 6.000% notes due February 2018 1,100 1,107 1,153 1,100 1,114 1,196 1.900% notes due July 2018 1,500 1,496 1,507 1,500 1,494 1,505 1.700% notes due February 2019 750 748 748 — — — 1.625% notes due March 2019 500 501 498 500 502 494 2.300% notes due December 2019 500 498 504 500 499 502 2.700% notes due July 2020 1,500 1,495 1,523 1,500 1,493 1,516 3.875% notes due October 2020 450 450 474 450 452 476 4.700% notes due February 2021 400 409 433 400 413 438 2.125% notes due March 2021 750 745 741 — — — 3.375% notes due November 2021 500 497 519 500 500 517 2.875% notes due December 2021 750 748 760 750 753 760 2.875% notes due March 2022 1,100 1,057 1,114 1,100 1,059 1,099 3.350% notes due July 2022 1,000 995 1,030 1,000 994 1,023 0.000% notes due November 2022 15 11 12 15 10 11 2.750% notes due February 2023 625 609 622 625 611 613 2.875% notes due March 2023 750 771 753 750 781 742 3.750% notes due July 2025 2,000 1,986 2,070 2,000 1,985 2,062 3.100% notes due March 2026 1,000 994 986 — — — 3.450% notes due January 2027 750 745 762 — — — 4.625% notes due July 2035 1,000 991 1,090 1,000 991 1,038 5.800% notes due March 2036 850 837 1,034 850 838 1,003 6.500% notes due June 2037 500 491 643 500 492 628 6.625% notes due November 2037 650 640 850 650 641 829 6.875% notes due February 2038 1,100 1,075 1,497 1,100 1,076 1,439 5.700% notes due October 2040 300 296 366 300 296 348 5.950% notes due February 2041 350 345 437 350 345 416 4.625% notes due November 2041 600 588 634 600 588 609 4.375% notes due March 2042 502 483 509 502 483 493 3.950% notes due October 2042 625 606 609 625 606 582 4.250% notes due March 2043 750 734 765 750 734 728 4.750% notes due July 2045 2,000 1,972 2,203 2,000 1,971 2,107 4.200% notes due January 2047 750 737 759 — — — Total commercial paper, term loan and long-term debt $ 33,022 $ 32,770 $ 34,728 $ 31,972 $ 31,801 $ 33,278 (a) In the first quarter of 2016, the Company adopted ASU 2015-03, retrospectively as required. See Note 2 for more information on the adoption of ASU 2015-03.
Schedule of Maturities of Long-term Debt [Table Text Block]	Maturities of commercial paper and long-term debt for the years ending December 31 are as follows: (in millions) 2017 $ 7,185 2018 2,622 2019 1,769 2020 1,955 2021 2,407 Thereafter 17,284

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Contingency [Line Items]
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	The components of the provision for income taxes for the years ended December 31 are as follows: (in millions) 2016 2015 2014 Current Provision: Federal $ 4,397 $ 4,155 $ 3,883 State and local 312 281 271 Total current provision 4,709 4,436 4,154 Deferred provision (benefit) 81 (73 ) (117 ) Total provision for income taxes $ 4,790 $ 4,363 $ 4,037
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	The reconciliation of the tax provision at the U.S. federal statutory rate to the provision for income taxes and the effective tax rate for the years ended December 31 is as follows: (in millions, except percentages) 2016 2015 2014 Tax provision at the U.S. federal statutory rate $ 4,152 35.0 % $ 3,581 35.0 % $ 3,380 35.0 % Health insurance industry tax 645 5.4 627 6.1 469 4.8 State income taxes, net of federal benefit 205 1.7 145 1.4 154 1.6 Share-based awards - excess tax benefit (158 ) (1.3 ) — — — — Non-deductible compensation 128 1.1 103 1.0 96 1.0 Other, net (182 ) (1.5 ) (93 ) (0.9 ) (62 ) (0.6 ) Provision for income taxes $ 4,790 40.4 % $ 4,363 42.6 % $ 4,037 41.8 %
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	Deferred income tax assets and liabilities are recognized for the differences between the financial and income tax reporting bases of assets and liabilities based on enacted tax rates and laws. The components of deferred income tax assets and liabilities as of December 31 are as follows: (in millions) 2016 2015 Deferred income tax assets: Accrued expenses and allowances $ 820 $ 739 U.S. federal and state net operating loss carryforwards 147 139 Share-based compensation 126 124 Nondeductible liabilities 236 205 Medical costs payable and other current liabilities 95 71 Non-U.S. tax loss carryforwards 434 244 Net unrealized losses on investments 55 — Other-domestic 194 214 Other-non-U.S. 175 130 Subtotal 2,282 1,866 Less: valuation allowances (55 ) (44 ) Total deferred income tax assets 2,227 1,822 Deferred income tax liabilities: U.S. federal and state intangible assets (3,055 ) (2,951 ) Non-U.S. goodwill and intangible assets (584 ) (397 ) Capitalized software (707 ) (574 ) Net unrealized gains on investments — (34 ) Depreciation and amortization (332 ) (312 ) Prepaid expenses (228 ) (205 ) Other-non-U.S. (82 ) (76 ) Total deferred income tax liabilities (4,988 ) (4,549 ) Net deferred income tax liabilities $ (2,761 ) $ (2,727 )
Summary of Positions for which Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Table Text Block]	A reconciliation of the beginning and ending amount of unrecognized tax benefits as of December 31 is as follows: (in millions) 2016 2015 2014 Gross unrecognized tax benefits, beginning of period $ 224 $ 92 $ 89 Gross increases: Current year tax positions 37 — — Prior year tax positions 24 55 4 Acquired reserves — 89 — Gross decreases: Prior year tax positions (4 ) (2 ) — Settlements (6 ) (1 ) — Statute of limitations lapses (12 ) (9 ) (1 ) Gross unrecognized tax benefits, end of period $ 263 $ 224 $ 92

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2016
Shareholders' Equity [Abstract]
Share Repurchase Activity	A summary of common share repurchases for the years ended December 31, 2016 and 2015 is as follows: Years Ended December 31, (in millions, except per share data) 2016 2015 Common share repurchases, shares 10 11 Common share repurchases, average price per share $ 128.97 $ 112.45 Common share repurchases, aggregate cost $ 1,280 $ 1,200 Board authorized shares remaining 51 61

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Option and SAR Activity [Table Text Block]	Stock option and SAR activity for the year ended December 31, 2016 is summarized in the table below: Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Life Aggregate Intrinsic Value (in millions) (in years) (in millions) Outstanding at beginning of period 34 $ 68 Granted 11 113 Exercised (8 ) 57 Forfeited (1 ) 103 Outstanding at end of period 36 84 6.6 $ 2,758 Exercisable at end of period 14 56 4.0 1,458 Vested and expected to vest, end of period 35 83 6.6 2,704
Restricted Share Activity [Table Text Block]	Restricted share activity for the year ended December 31, 2016 is summarized in the table below: (shares in millions) Shares Weighted-Average Grant Date Fair Value per Share Nonvested at beginning of period 7 $ 82 Granted 3 115 Vested (3 ) 76 Nonvested at end of period 7 96
Other Share-Based Compensation Data [Table Text Block]	Other Share-Based Compensation Data (in millions, except per share amounts) For the Years Ended December 31, 2016 2015 2014 Stock Options and SARs Weighted-average grant date fair value of shares granted, per share $ 20 $ 22 $ 22 Total intrinsic value of stock options and SARs exercised 595 482 526 Restricted Shares Weighted-average grant date fair value of shares granted, per share 115 110 71 Total fair value of restricted shares vested $ 274 $ 460 $ 437 Employee Stock Purchase Plan Number of shares purchased 2 2 2 Share-Based Compensation Items Share-based compensation expense, before tax $ 485 $ 406 $ 364 Share-based compensation expense, net of tax effects 417 348 314 Income tax benefit realized from share-based award exercises 236 247 231 (in millions, except years) December 31, 2016 Unrecognized compensation expense related to share awards $ 516 Weighted-average years to recognize compensation expense 1.3
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	The principal assumptions the Company used in calculating grant-date fair value for stock options and SARs were as follows: For the Years Ended December 31, 2016 2015 2014 Risk-free interest rate 1.2% - 1.4% 1.6% - 1.7% 1.7% - 1.8% Expected volatility 20.8% - 22.5% 22.3% - 24.1% 24.1% - 39.6% Expected dividend yield 1.8% 1.4% - 1.7% 1.6% - 1.9% Forfeiture rate 5.0% 5.0% 5.0% Expected life in years 5.6 - 5.9 5.5 - 6.1 5.4

Commitments and Contingencies36

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2016
Operating Leased Assets [Line Items]
Operating Leases of Lessee Disclosure [Table Text Block]	As of December 31, 2016 , future minimum annual lease payments, net of sublease income, under all non-cancelable operating leases were as follows: (in millions) Future Minimum Lease Payments 2017 $ 453 2018 416 2019 355 2020 314 2021 273 Thereafter 499

Segment Financial Information37

Segment Financial Information (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Segment Financial Information [Table Text Block]	The following table presents the reportable segment financial information: Optum (in millions) UnitedHealthcare OptumHealth OptumInsight OptumRx Optum Eliminations Optum Corporate and Eliminations Consolidated 2016 Revenues - external customers: Premiums $ 140,455 $ 3,663 $ — $ — $ — $ 3,663 $ — $ 144,118 Products 1 48 103 26,506 — 26,657 — 26,658 Services 7,514 2,498 2,670 554 — 5,722 — 13,236 Total revenues - external customers 147,970 6,209 2,773 27,060 — 36,042 — 184,012 Total revenues - intersegment — 10,491 4,559 33,372 (1,088 ) 47,334 (47,334 ) — Investment and other income 611 208 1 8 — 217 — 828 Total revenues $ 148,581 $ 16,908 $ 7,333 $ 60,440 $ (1,088 ) $ 83,593 $ (47,334 ) $ 184,840 Earnings from operations $ 7,307 $ 1,428 $ 1,513 $ 2,682 $ — $ 5,623 $ — $ 12,930 Interest expense — — — — — — (1,067 ) (1,067 ) Earnings before income taxes $ 7,307 $ 1,428 $ 1,513 $ 2,682 $ — $ 5,623 $ (1,067 ) $ 11,863 Total assets $ 70,505 $ 18,656 $ 9,017 $ 29,066 $ — $ 56,739 $ (4,434 ) $ 122,810 Purchases of property, equipment and capitalized software 640 345 571 149 — 1,065 — 1,705 Depreciation and amortization 724 297 559 475 — 1,331 — 2,055 2015 Revenues - external customers: Premiums $ 124,011 $ 3,152 $ — $ — $ — $ 3,152 $ — $ 127,163 Products 2 31 108 17,171 — 17,310 — 17,312 Services 6,776 2,375 2,390 381 — 5,146 — 11,922 Total revenues - external customers 130,789 5,558 2,498 17,552 — 25,608 — 156,397 Total revenues - intersegment — 8,216 3,697 30,718 (791 ) 41,840 (41,840 ) — Investment and other income 554 153 1 2 — 156 — 710 Total revenues $ 131,343 $ 13,927 $ 6,196 $ 48,272 $ (791 ) $ 67,604 $ (41,840 ) $ 157,107 Earnings from operations $ 6,754 $ 1,240 $ 1,278 $ 1,749 $ — $ 4,267 $ — $ 11,021 Interest expense — — — — — — (790 ) (790 ) Earnings before income taxes $ 6,754 $ 1,240 $ 1,278 $ 1,749 $ — $ 4,267 $ (790 ) $ 10,231 Total assets (a) $ 64,212 $ 14,600 $ 8,335 $ 26,844 $ — $ 49,779 $ (2,737 ) $ 111,254 Purchases of property, equipment and capitalized software 653 252 572 79 — 903 — 1,556 Depreciation and amortization 718 251 492 232 — 975 — 1,693 2014 Revenues - external customers: Premiums $ 112,645 $ 2,657 $ — $ — $ — $ 2,657 $ — $ 115,302 Products 3 18 96 4,125 — 4,239 — 4,242 Services 6,516 1,300 2,224 111 — 3,635 — 10,151 Total revenues - external customers 119,164 3,975 2,320 4,236 — 10,531 — 129,695 Total revenues - intersegment — 6,913 2,906 27,740 (489 ) 37,070 (37,070 ) — Investment and other income 634 144 1 — — 145 — 779 Total revenues $ 119,798 $ 11,032 $ 5,227 $ 31,976 $ (489 ) $ 47,746 $ (37,070 ) $ 130,474 Earnings from operations $ 6,992 $ 1,090 $ 1,002 $ 1,190 $ — $ 3,282 $ — $ 10,274 Interest expense — — — — — — (618 ) (618 ) Earnings before income taxes $ 6,992 $ 1,090 $ 1,002 $ 1,190 $ — $ 3,282 $ (618 ) $ 9,656 Total assets (a) $ 62,405 $ 11,148 $ 8,112 $ 5,474 $ — $ 24,734 $ (839 ) $ 86,300 Purchases of property, equipment and capitalized software 773 212 484 56 — 752 — 1,525 Depreciation and amortization 772 179 433 94 — 706 — 1,478 (a) In the first quarter of 2016, the Company adopted ASU 2015-03, retrospectively as required. See Note 2 for more information on the adoption of ASU 2015-03.

Quarterly Financial Data (Una38

Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2016
Schedule of Quarterly Financial Information [Table Text Block]	Selected quarterly financial information for all quarters of 2016 and 2015 is as follows: For the Quarter Ended (in millions, except per share data) March 31 June 30 September 30 December 31 2016 Revenues $ 44,527 $ 46,485 $ 46,293 $ 47,535 Operating costs 41,567 43,282 42,713 44,348 Earnings from operations 2,960 3,203 3,580 3,187 Net earnings 1,627 1,760 1,978 1,708 Net earnings attributable to UnitedHealth Group common shareholders 1,611 1,754 1,968 1,684 Net earnings per share attributable to UnitedHealth Group common shareholders: Basic 1.69 1.84 2.07 1.77 Diluted 1.67 1.81 2.03 1.74 2015 Revenues $ 35,756 $ 36,263 $ 41,489 $ 43,599 Operating costs 33,116 33,368 38,471 41,131 Earnings from operations 2,640 2,895 3,018 2,468 Net earnings 1,413 1,585 1,618 1,252 Net earnings attributable to UnitedHealth Group common shareholders 1,413 1,585 1,597 1,218 Net earnings per share attributable to UnitedHealth Group common shareholders: Basic 1.48 1.66 1.68 1.28 Diluted 1.46 1.64 1.65 1.26

Schedule I (Tables)

Schedule I (Tables)	12 Months Ended
	Dec. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Schedule of Maturities of Long-term Debt [Table Text Block]	Maturities of commercial paper and long-term debt for the years ending December 31 are as follows: (in millions) 2017 $ 7,185 2018 2,622 2019 1,769 2020 1,955 2021 2,407 Thereafter 17,284
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Condensed Balance Sheet [Table Text Block]	Condensed Financial Information of Registrant (Parent Company Only) UnitedHealth Group Condensed Balance Sheets (in millions, except per share data) December 31, December 31, Assets Current assets: Cash and cash equivalents $ 180 $ 29 Short-term notes receivable from subsidiaries 755 — Other current assets 140 313 Total current assets 1,075 342 Equity in net assets of subsidiaries 60,593 56,316 Long-term notes receivable from subsidiaries 9,912 9,679 Other assets 248 199 Total assets $ 71,828 $ 66,536 Liabilities and shareholders’ equity Current liabilities: Accounts payable and accrued liabilities $ 452 $ 449 Note payable to subsidiary 280 310 Commercial paper and current maturities of long-term debt 7,113 6,587 Total current liabilities 7,845 7,346 Long-term debt, less current maturities 25,657 25,215 Other liabilities 52 145 Total liabilities 33,554 32,706 Commitments and contingencies (Note 4) Shareholders’ equity: Preferred stock, $0.001 par value -10 shares authorized; no shares issued or outstanding — — Common stock, $0.01 par value - 3,000 shares authorized; 952 and 953 issued and outstanding 10 10 Additional paid-in capital — 29 Retained earnings 40,945 37,125 Accumulated other comprehensive loss (2,681 ) (3,334 ) Total UnitedHealth Group shareholders’ equity 38,274 33,830 Total liabilities and shareholders’ equity $ 71,828 $ 66,536
Condensed Statement of Comprehensive Income [Table Text Block]	Condensed Financial Information of Registrant (Parent Company Only) UnitedHealth Group Condensed Statements of Comprehensive Income For the Years Ended December 31, (in millions) 2016 2015 2014 Revenues: Investment and other income $ 522 $ 396 $ 293 Total revenues 522 396 293 Operating costs: Operating costs (22 ) (17 ) 1 Interest expense 995 717 554 Total operating costs 973 700 555 Loss before income taxes (451 ) (304 ) (262 ) Benefit for income taxes 165 111 96 Loss of parent company (286 ) (193 ) (166 ) Equity in undistributed income of subsidiaries 7,303 6,006 5,785 Net earnings 7,017 5,813 5,619 Other comprehensive income (loss) 653 (1,942 ) (484 ) Comprehensive income $ 7,670 $ 3,871 $ 5,135
Condensed Cash Flow Statement [Table Text Block]	Condensed Financial Information of Registrant (Parent Company Only) UnitedHealth Group Condensed Statements of Cash Flows For the Years Ended December 31, (in millions) 2016 2015 2014 Operating activities Cash flows from operating activities $ 4,294 $ 1,727 $ 7,445 Investing activities Issuance of notes to subsidiaries (824 ) (5,064 ) (436 ) Cash paid for acquisitions (2,292 ) (12,270 ) (1,852 ) Return of capital to parent company 2,143 4,375 — Capital contributions to subsidiaries (765 ) (1,109 ) (704 ) Other, net 168 140 (9 ) Cash flows used for investing activities (1,570 ) (13,928 ) (3,001 ) Financing activities Common stock repurchases (1,280 ) (1,200 ) (4,008 ) Proceeds from common stock issuances 429 402 462 Cash dividends paid (2,261 ) (1,786 ) (1,362 ) (Repayments of) proceeds from commercial paper, net (382 ) 3,666 (794 ) Proceeds from issuance of long-term debt 3,968 11,982 1,997 Repayments of long-term debt (2,596 ) (1,041 ) (812 ) Other, net (451 ) (352 ) (190 ) Cash flows (used for) from financing activities (2,573 ) 11,671 (4,707 ) Increase (decrease) in cash and cash equivalents 151 (530 ) (263 ) Cash and cash equivalents, beginning of period 29 559 822 Cash and cash equivalents, end of period $ 180 $ 29 $ 559 Supplemental cash flow disclosures Cash paid for interest $ 974 $ 573 $ 578 Cash paid for income taxes 4,557 4,294 4,028
Schedule of Maturities of Long-term Debt [Table Text Block]	Maturities of commercial paper and long-term debt for the years ending December 31 are as follows: (in millions) 2017 $ 7,105 2018 2,600 2019 1,750 2020 1,950 2021 2,400 Thereafter 17,217

Basis of Presentation, Uses o40

Basis of Presentation, Uses of Estimates and Significant Accounting Policies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Accounts payable and accrued liabilities	$ 13,361	$ 11,994
Other current receivables	7,499	6,801
Goodwill, Impairment Loss	$ 0
Number Of Days Notice Required To Cancel Health Insurance Contract	30 days
Intangible Asset Impairment	$ 0
Other Current Liabilities [Member]
Health savings account deposits	5,700	3,600
Checks Outstanding [Member]
Accounts payable and accrued liabilities	$ 1,500	1,600
Restricted Stock [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	2 years
Restricted Stock [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	5 years
Stock Options and SARs [Member] [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	4 years
Share-based Compensation Arrangement by Share-based Payment Plan Award, Options, Award Exercisable Period	10 years
Employee Stock Purchase Plan (ESPP) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Offering Date	85.00%
Pharmaceutical Manufacturer Rebates Receivable [Member]
Other current receivables	$ 3,300	$ 2,600
Accounting Standards Update 2016-09 [Member]
New Accounting Pronouncement or Change in Accounting Principle, Description of Transition Method	Modified Retrospective and Prospective
New Accounting Pronouncement, Transition Guidance Not Significant or Not Practical	Impact is not material
Accounting Standards Update 2015-17 [Member]
New Accounting Pronouncement or Change in Accounting Principle, Description of Transition Method	Prospective
Accounting Standards Update 2015-03 [Member]
New Accounting Pronouncement or Change in Accounting Principle, Description of Transition Method	Retrospective
Accounting Standards Update 2015-03 [Member] | 2015 Reclassification from Other Assets to Long-Term Debt, Less Current Maturities [Member] [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 129
Accounting Standards Update 2015-03 [Member] | 2014 Reclassification from Other Assets to Long-Term Debt, Less Current Maturities [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 82
Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncement or Change in Accounting Principle, Description of Transition Method	Modified Retrospective
New Accounting Pronouncement, Transition Guidance Not Significant or Not Practical	Impact is not material
Health Insurance Product Line [Member]
Short-duration Insurance Contracts, Historical Claims Duration, First 90 Days	0.90

Basis of Presentation, Uses o41

Basis of Presentation, Uses of Estimates and Significant Accounting Policies Medicare Part D (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Other current receivables	$ 7,499	$ 6,801
Other current liabilities	10,339	7,798
CMS Subsidies [Member]
Other current receivables	934	1,703
Other current liabilities	0	0
Drug Discount [Member]
Other current receivables	543	423
Other current liabilities	267	58
Risk-Share [Member]
Other current receivables	0	0
Other current liabilities	$ 471	$ 496

Basis of Presentation, Uses o42

Basis of Presentation, Uses of Estimates and Significant Accounting Policies Useful lives for property, equipment and capitalized software (Details)	12 Months Ended
	Dec. 31, 2016
Furniture, Fixtures and equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful Life	3 years
Furniture, Fixtures and equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful Life	7 years
Buildings [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful Life	35 years
Buildings [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful Life	40 years
Capitalized software [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful Life	3 years
Capitalized software [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful Life	5 years

Basis of Presentation, Uses o43

Basis of Presentation, Uses of Estimates and Significant Accounting Policies Redeemable Noncontrolling Interests (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Noncontrolling Interest [Line Items]
Redeemable noncontrolling interest, beginning of period	$ 1,736
Acquisitions		$ 9
Redemptions	(143)
Distributions	(32)	(140)
Fair value and other adjustments	(216)	(225)
Redeemable Noncontrolling Interest, end of period	2,012	1,736
Redeemable Noncontrolling Interests [Member]
Noncontrolling Interest [Line Items]
Redeemable noncontrolling interest, beginning of period	1,736	1,388
Net earnings	16	29
Acquisitions	34	196
Redemptions	(123)	(116)
Distributions	(11)	(19)
Fair value and other adjustments	360	258
Redeemable Noncontrolling Interest, end of period	$ 2,012	$ 1,736

Investments (Narrative) (Detail

Investments (Narrative) (Details)	Dec. 31, 2016positions
Investment [Line Items]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	12,000
Total number of security positions	27,000

Investments (Short-Term and Lon

Investments (Short-Term and Long-Term Investments) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Schedule of Investments [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	$ 24,330	$ 18,539
Securities, Available for sale Debt Securities, Gross Unrealized Gains	92	209
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(243)	(117)
Available-for-sale Securities, Debt Securities	24,179	18,631
Available-for-sale Equity Securities, Amortized Cost Basis	2,036	1,638
Securities, Available for sale Equity Securities, Gross Unrealized Gains	52	58
Securities, Available for sale Equity Securities, Gross Unrealized Losses	(47)	(57)
Available-for-sale Securities, Equity Securities	2,041	1,639
Held-to-maturity securities, Amortized Cost	493	510
Securities, Held to maturity, Unrecognized Holding Gain	1	1
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0	0
Held-to-maturity Securities, Fair Value	494	511
Total investments, Amortized Cost	26,859	20,687
Total investments, Gross Unrealized Gains	145	268
Total investments, Gross Unrealized Losses	(290)	(174)
Investments, Fair Value Disclosure	26,714	20,781
Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Debt Securities	24,179	18,631
U.S. Government and Agency Obligations [Member]
Schedule of Investments [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	2,294	1,982
Securities, Available for sale Debt Securities, Gross Unrealized Gains	1	1
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(31)	(6)
Available-for-sale Securities, Debt Securities	2,264	1,977
Held-to-maturity securities, Amortized Cost	250	163
Securities, Held to maturity, Unrecognized Holding Gain	1	1
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0	0
Held-to-maturity Securities, Fair Value	251	164
State and Municipal Obligations [Member]
Schedule of Investments [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	7,120	6,022
Securities, Available for sale Debt Securities, Gross Unrealized Gains	40	149
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(101)	(3)
Available-for-sale Securities, Debt Securities	7,059	6,168
Held-to-maturity securities, Amortized Cost	5	8
Securities, Held to maturity, Unrecognized Holding Gain	0	0
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0	0
Held-to-maturity Securities, Fair Value	5	8
Corporate Obligations [Member]
Schedule of Investments [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	10,944	7,446
Securities, Available for sale Debt Securities, Gross Unrealized Gains	41	41
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(58)	(81)
Available-for-sale Securities, Debt Securities	10,927	7,406
Held-to-maturity securities, Amortized Cost	238	339
Securities, Held to maturity, Unrecognized Holding Gain	0	0
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0	0
Held-to-maturity Securities, Fair Value	238	339
U.S. Agency Mortgage-Backed Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	2,963	2,127
Securities, Available for sale Debt Securities, Gross Unrealized Gains	7	13
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(43)	(16)
Available-for-sale Securities, Debt Securities	2,927	2,124
Non-U.S. Agency Mortgage-Backed Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	1,009	962
Securities, Available for sale Debt Securities, Gross Unrealized Gains	3	5
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(10)	(11)
Available-for-sale Securities, Debt Securities	$ 1,002	$ 956

Investments (Amortized Cost and

Investments (Amortized Cost and Fair Value of Available-for-Sale Debt Securities by Contractual Maturity) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Schedule of Investments [Line Items]
Due in one year or less, Amortized Cost	$ 2,893
Due after one year through five years, Amortized Cost	9,646
Due after five years through ten years, Amortized Cost	5,706
Due after ten years, Amortized Cost	2,113
Total debt securities - available-for-sale, Amortized Cost	24,330	$ 18,539
Due in one year or less, Fair Value	2,895
Due after one year through five years, Fair Value	9,625
Due after five years through ten years, Fair Value	5,645
Due after ten years, Fair Value	2,085
Available-for-sale Securities, Debt Securities	24,179	18,631
Held-to-maturity Securities, Debt Maturities, within One Year, Net Carrying Amount	151
Held-to-maturity Securities, Debt Maturities, Next Twelve Months, Fair Value	151
Held-to-maturity Securities, Debt Maturities, after One Through Five Years, Net Carrying Amount	153
Held-to-maturity Securities, Debt Maturities, Year Two Through Five, Fair Value	153
Held-to-maturity Securities, Debt Maturities, after Five Through Ten Years, Net Carrying Amount	124
Held-to-maturity Securities, Debt Maturities, Year Six Through Ten, Fair Value	124
Held-to-maturity Securities, Debt Maturities, after Ten Years, Net Carrying Amount	65
Held-to-maturity Securities, Debt Maturities, after Ten Years, Fair Value	66
Held-to-maturity Securities	493	510
Held-to-maturity Securities, Fair Value	494	511
U.S. Agency Mortgage-Backed Securities [Member]
Schedule of Investments [Line Items]
Mortgage-backed securities, Amortized Cost	2,963
Total debt securities - available-for-sale, Amortized Cost	2,963	2,127
Available-for-sale Securities, Debt Securities	2,927	2,124
Mortgage-backed securities, Fair Value	2,927
Non-U.S. Agency Mortgage-Backed Securities [Member]
Schedule of Investments [Line Items]
Mortgage-backed securities, Amortized Cost	1,009
Total debt securities - available-for-sale, Amortized Cost	1,009	962
Available-for-sale Securities, Debt Securities	1,002	$ 956
Mortgage-backed securities, Fair Value	$ 1,002

Investments (Fair Value of Avai

Investments (Fair Value of Available-For-Sale Investments with Gross Unrealized Losses by Investment Type and Length of Time That Individual Securities Have Been in a Continuous Unrealized Loss Position) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Debt Securities [Member]
Schedule of Investments [Line Items]
Less Than 12 Months, Fair Value	$ 14,089	$ 8,649
Less Than 12 Months, Gross Unrealized Losses	(235)	(91)
Greater Than 12 Months, Fair Value	313	582
Greater Than 12 Months, Gross Unrealized Losses	(8)	(26)
Total, Fair Value	14,402	9,231
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(243)	(117)
U.S. Government and Agency Obligations [Member]
Schedule of Investments [Line Items]
Less Than 12 Months, Fair Value	1,794	1,473
Less Than 12 Months, Gross Unrealized Losses	(31)	(6)
Total, Fair Value	1,794	1,473
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(31)	(6)
State and Municipal Obligations [Member]
Schedule of Investments [Line Items]
Less Than 12 Months, Fair Value	4,376	650
Less Than 12 Months, Gross Unrealized Losses	(101)	(3)
Total, Fair Value	4,376	650
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(101)	(3)
Corporate Obligations [Member]
Schedule of Investments [Line Items]
Less Than 12 Months, Fair Value	5,128	4,629
Less Than 12 Months, Gross Unrealized Losses	(56)	(63)
Greater Than 12 Months, Fair Value	137	339
Greater Than 12 Months, Gross Unrealized Losses	(2)	(18)
Total, Fair Value	5,265	4,968
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(58)	(81)
U.S. Agency Mortgage-Backed Securities [Member]
Schedule of Investments [Line Items]
Less Than 12 Months, Fair Value	2,247	1,304
Less Than 12 Months, Gross Unrealized Losses	(40)	(12)
Greater Than 12 Months, Fair Value	79	116
Greater Than 12 Months, Gross Unrealized Losses	(3)	(4)
Total, Fair Value	2,326	1,420
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(43)	(16)
Non-U.S. Agency Mortgage-Backed Securities [Member]
Schedule of Investments [Line Items]
Less Than 12 Months, Fair Value	544	593
Less Than 12 Months, Gross Unrealized Losses	(7)	(7)
Greater Than 12 Months, Fair Value	97	127
Greater Than 12 Months, Gross Unrealized Losses	(3)	(4)
Total, Fair Value	641	720
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(10)	(11)
Equity Securities [Member]
Schedule of Investments [Line Items]
Less Than 12 Months, Fair Value	93	112
Less Than 12 Months, Gross Unrealized Losses	(5)	(11)
Greater Than 12 Months, Fair Value	91	89
Greater Than 12 Months, Gross Unrealized Losses	(42)	(46)
Total, Fair Value	184	201
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (47)	$ (57)

Investments (Net Realized Gains

Investments (Net Realized Gains) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Income tax effect (included in Provision for Income Taxes on the Consolidated Statements of Operations)	$ (4,790)	$ (4,363)	$ (4,037)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Schedule of Available-for-sale Securities [Line Items]
Total other than temporary impairment recognized in earnings	(45)	(22)	(26)
Gross realized losses from sales	(44)	(28)	(47)
Gross realized gains from sales	255	191	284
Net realized gains (included in investment and other income on the Consolidated Statements of Operations)	166	141	211
Income tax effect (included in Provision for Income Taxes on the Consolidated Statements of Operations)	(60)	(53)	(77)
Realized gains, net of taxes	$ 106	$ 88	$ 134

Fair Value (Narrative) (Details

Fair Value (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fair Value [Line Items]
Transfers from level 1 to level 2-Assets	$ 0	$ 0
Transfers from level 1 to level 2-Liabilities	0	0
Transfer from level 2 to level 1-Assets	0	0
Transfer from level 2 to level 1-Liabilities	0	0
Transfers Into Level 3	0	0
Transfers out of Level 3	0	0
Fair Value, Measurements, Nonrecurring [Member]
Fair Value [Line Items]
Significant fair value adjustments for assets and liabilities measured on a nonrecurring basis	0	$ 0
Fair Value, Measurements, Recurring [Member] | Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value [Line Items]
Available-for-sale Securities, Debt Securities	$ 102

Fair Value (Financial Assets an

Fair Value (Financial Assets and Liabilities, Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 10,430	$ 10,923
Available-for-sale Securities, Debt Securities	24,179	18,631
Available-for-sale Securities, Equity Securities	2,041	1,639
Assets under management	3,105	2,998
Interest rate swap assets	55	93
Total assets at fair value	$ 39,810	$ 34,284
Percentage of total assets at fair value	100.00%	100.00%
Interest rate swap liabilities	$ 14	$ 11
Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	24,179	18,631
U.S. Government and Agency Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	2,264	1,977
State and Municipal Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	7,059	6,168
Corporate Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	10,927	7,406
U.S. Agency Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	2,927	2,124
Non-U.S. Agency Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	1,002	956
Quoted Prices in Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	10,386	10,906
Available-for-sale Securities, Equity Securities	1,591	1,223
Assets under management	1,064	832
Interest rate swap assets	0	0
Total assets at fair value	$ 15,079	$ 14,745
Percentage of total assets at fair value	38.00%	43.00%
Interest rate swap liabilities	$ 0	$ 0
Quoted Prices in Active Markets (Level 1) [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	2,038	1,784
Quoted Prices in Active Markets (Level 1) [Member] | U.S. Government and Agency Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	2,017	1,779
Quoted Prices in Active Markets (Level 1) [Member] | State and Municipal Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	0	0
Quoted Prices in Active Markets (Level 1) [Member] | Corporate Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	21	5
Quoted Prices in Active Markets (Level 1) [Member] | U.S. Agency Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	0	0
Quoted Prices in Active Markets (Level 1) [Member] | Non-U.S. Agency Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	0	0
Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	44	17
Available-for-sale Securities, Equity Securities	13	14
Assets under management	2,041	2,166
Interest rate swap assets	55	93
Total assets at fair value	$ 24,192	$ 19,039
Percentage of total assets at fair value	61.00%	56.00%
Interest rate swap liabilities	$ 14	$ 11
Other Observable Inputs (Level 2) [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	22,039	16,749
Other Observable Inputs (Level 2) [Member] | U.S. Government and Agency Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	247	198
Other Observable Inputs (Level 2) [Member] | State and Municipal Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	7,059	6,168
Other Observable Inputs (Level 2) [Member] | Corporate Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	10,804	7,308
Other Observable Inputs (Level 2) [Member] | U.S. Agency Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	2,927	2,124
Other Observable Inputs (Level 2) [Member] | Non-U.S. Agency Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	1,002	951
Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Available-for-sale Securities, Equity Securities	437	402
Assets under management	0	0
Interest rate swap assets	0	0
Total assets at fair value	$ 539	$ 500
Percentage of total assets at fair value	1.00%	1.00%
Interest rate swap liabilities	$ 0	$ 0
Unobservable Inputs (Level 3) [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	102	98
Unobservable Inputs (Level 3) [Member] | U.S. Government and Agency Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	0	0
Unobservable Inputs (Level 3) [Member] | State and Municipal Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	0	0
Unobservable Inputs (Level 3) [Member] | Corporate Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	102	93
Unobservable Inputs (Level 3) [Member] | U.S. Agency Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	0	0
Unobservable Inputs (Level 3) [Member] | Non-U.S. Agency Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	$ 0	$ 5

Fair Value (Financial Assets 51

Fair Value (Financial Assets and Liabilities, Not Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	$ 494	$ 511
Held-to-maturity Securities	493	510
Debt and other financing obligations, carrying value	32,770	31,801
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	494	511
Fair Value, Measurements, Nonrecurring [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	271	255
Fair Value, Measurements, Nonrecurring [Member] | Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	8	10
Fair Value, Measurements, Nonrecurring [Member] | Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	215	246
U.S. Government and Agency Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	250	163
U.S. Government and Agency Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	251	164
U.S. Government and Agency Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	251	164
U.S. Government and Agency Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member] | Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	0	0
U.S. Government and Agency Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member] | Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	0	0
State and Municipal Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	5	8
State and Municipal Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	5	8
State and Municipal Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	0	0
State and Municipal Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member] | Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	0	0
State and Municipal Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member] | Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	5	8
Corporate Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	238	339
Corporate Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	238	339
Corporate Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	20	91
Corporate Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member] | Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	8	10
Corporate Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member] | Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	210	238
Other Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets	471	500
Other Assets [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	476	493
Other Assets [Member] | Fair Value, Measurements, Nonrecurring [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	0	0
Other Assets [Member] | Fair Value, Measurements, Nonrecurring [Member] | Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	476	493
Other Assets [Member] | Fair Value, Measurements, Nonrecurring [Member] | Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	0	0
Long-term Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt and other financing obligations, carrying value	29,337	27,978
Long-term Debt [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt and other financing obligations	31,295	29,455
Long-term Debt [Member] | Fair Value, Measurements, Nonrecurring [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt and other financing obligations	0	0
Long-term Debt [Member] | Fair Value, Measurements, Nonrecurring [Member] | Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt and other financing obligations	31,295	29,455
Long-term Debt [Member] | Fair Value, Measurements, Nonrecurring [Member] | Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt and other financing obligations	$ 0	$ 0

Fair Value (Reconciliation of A

Fair Value (Reconciliation of Assets Measured at Fair Value on a Recurring Basis Using Level 3 Inputs) (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 500	$ 384	$ 311
Purchases	112	133	137
Sales	(38)	(28)	(181)
Net unrealized gains (losses) in accumulated other comprehensive income	(12)	7	7
Net realized gains (losses) in investment and other income	(23)	4	110
Balance at end of period	539	500	384
Debt Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	98	74	42
Purchases	12	27	32
Sales	(9)	(4)	(1)
Net unrealized gains (losses) in accumulated other comprehensive income	1	2	1
Net realized gains (losses) in investment and other income	0	(1)	0
Balance at end of period	102	98	74
Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	402	310	269
Purchases	100	106	105
Sales	(29)	(24)	(180)
Net unrealized gains (losses) in accumulated other comprehensive income	(13)	5	6
Net realized gains (losses) in investment and other income	(23)	5	110
Balance at end of period	$ 437	$ 402	$ 310

Fair Value Fair Value Inputs As

Fair Value Fair Value Inputs Assets Quantitative Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Venture Capital Funds [Member] | Market Approach Valuation Technique [Member] | Comparable Companies [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	$ 404
Venture Capital Funds [Member] | Market Approach Valuation Technique [Member] | Recent Transactions [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	$ 33
Minimum [Member] | Comparable Companies [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Revenue Multiple	1
Fair Value Inputs, Earnings before Interest, Taxes, Depreciation, and Amortization Multiple	8
Maximum [Member] | Comparable Companies [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Revenue Multiple	6
Fair Value Inputs, Earnings before Interest, Taxes, Depreciation, and Amortization Multiple	12
Unobservable Inputs (Level 3) [Member] | Equity Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	$ 437

Property, Plant, and Capitali54

Property, Plant, and Capitalized Software (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Depreciation	$ 698	$ 613	$ 532
Capitalized Computer Software, Amortization	$ 475	$ 430	$ 422

Property, Plant, and Capitali55

Property, Plant, and Capitalized Software Property Plant and Equipment Table (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Land and improvements	$ 324	$ 237
Buildings and improvements	3,148	2,420
Computer equipment	2,021	1,945
Furniture and fixtures	999	790
Less accumulated depreciation	(2,621)	(2,163)
Property and equipment, net	3,871	3,229
Capitalized software	3,158	2,642
Less accumulated amortization	(1,128)	(1,010)
Capitalized software, net	2,030	1,632
Total property, equipment and capitalized software, net	$ 5,901	$ 4,861

Goodwill and Intangible Asset56

Goodwill and Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Goodwill		$ 47,584	$ 44,453	$ 32,940
Amortization of Intangible Assets		$ 882	$ 650	$ 524
Catamaran [Member]
Finite-Lived Intangible Assets [Line Items]
Payments to Acquire Businesses, Gross	$ 14,300
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles and Goodwill	16,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	5,400
Goodwill	$ 10,600

Goodwill and Intangible Asset57

Goodwill and Intangible Assets Changes in the Carrying Amount of Goodwill by Reporting Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 44,453	$ 32,940
Acquisitions	2,596	12,766
Foreign currency effects and adjustments, net	535	(1,253)
Goodwill, Ending Balance	47,584	44,453
UnitedHealthcare [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	22,925	24,030
Acquisitions	526	128
Foreign currency effects and adjustments, net	403	(1,233)
Goodwill, Ending Balance	23,854	22,925
OptumHealth [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	5,660	3,834
Acquisitions	683	1,817
Foreign currency effects and adjustments, net	(21)	9
Goodwill, Ending Balance	6,322	5,660
OptumInsight [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	4,296	4,236
Acquisitions	0	89
Foreign currency effects and adjustments, net	153	(29)
Goodwill, Ending Balance	4,449	4,296
OptumRx [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	11,572	840
Acquisitions	1,387	10,732
Foreign currency effects and adjustments, net	0	0
Goodwill, Ending Balance	$ 12,959	$ 11,572

Goodwill and Intangible Asset58

Goodwill and Intangible Assets Gross carrying value, accumulated amortization and net carrying value of intangible assets (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	$ 12,388	$ 11,519
Finite-Lived Intangible Assets, Accumulated Amortization	(3,847)	(3,128)
Intangible Assets, Net (Excluding Goodwill)	8,541	8,391
Customer-Related Intangible Assets [Member]
Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	10,942	10,270
Finite-Lived Intangible Assets, Accumulated Amortization	(3,416)	(2,796)
Intangible Assets, Net (Excluding Goodwill)	7,526	7,474
Trademarks and Technology [Member]
Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	720	682
Finite-Lived Intangible Assets, Accumulated Amortization	(323)	(249)
Intangible Assets, Net (Excluding Goodwill)	397	433
Trademarks and Trade Names [Member]
Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	468	358
Finite-Lived Intangible Assets, Accumulated Amortization	0	0
Intangible Assets, Net (Excluding Goodwill)	468	358
Other Intangible Assets [Member]
Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	258	209
Finite-Lived Intangible Assets, Accumulated Amortization	(108)	(83)
Intangible Assets, Net (Excluding Goodwill)	$ 150	$ 126

Goodwill and Intangible Asset59

Goodwill and Intangible Assets Weighted-average useful lives assigned to finite-lived intangible assets acquired in business combinations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	$ 889	$ 5,712
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	16 years	19 years
Customer-Related Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	$ 785	$ 5,518
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	17 years	19 years
Trademarks and Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	$ 82	$ 194
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	4 years	4 years
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	$ 22	$ 0
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	5 years

Goodwill and Intangible Asset60

Goodwill and Intangible Assets Amortization Expense relating to Intangible Assets (Details) $ in Millions	Dec. 31, 2016USD ($)
Finite-Lived Intangible Assets [Line Items]
2,017	$ 865
2,018	755
2,019	679
2,020	596
2,021	$ 536

Medical Costs Payable (Details)

Medical Costs Payable (Details) - USD ($) $ in Billions	Dec. 31, 2016	Dec. 31, 2015
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred but Not Reported (IBNR) Claims, Amount	$ 11.6	$ 9.8

Medical Costs Payable Rollforwa

Medical Costs Payable Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Medical costs payable, beginning of period	$ 14,330	$ 12,040	$ 11,575
Reported medical costs:
Current year	117,258	104,195	94,053
Prior years	(220)	(320)	(420)
Total reported medical costs	117,038	103,875	93,633
Medical payments:
Payments for current year	(101,696)	(90,630)	(82,750)
Payments for prior years	(13,281)	(10,955)	(10,418)
Total medical payments	(114,977)	(101,585)	(93,168)
Medical costs payable, end of period	$ 16,391	$ 14,330	$ 12,040

Medical Costs Payable, Incurred

Medical Costs Payable, Incurred and Paid Medical Cost Development (Details) - Health Insurance Product Line [Member] - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Net Incurred Medical Costs	$ 221,231
Net Cumulative Medical Payments	(205,581)
Net remaining outstanding liabilities prior to 2015	741
Total Medical costs payable	16,391
Short-duration Insurance Contracts, Accident Year 2015 [Member]
Net Incurred Medical Costs	103,973	$ 104,195
Net Cumulative Medical Payments	(103,885)	$ (90,630)
Short-duration Insurance Contracts, Accident Year 2016 [Member]
Net Incurred Medical Costs	117,258
Net Cumulative Medical Payments	$ (101,696)

Commercial Paper and Long-Ter64

Commercial Paper and Long-Term Debt (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)banks	Dec. 31, 2015USD ($)
Commercial Paper [Member]
Debt Instrument [Line Items]
Short-term Debt, Weighted Average Interest Rate	0.90%
Five Year $3.0 Billion Credit Facility [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long-term Line of Credit	$ 0
Line of Credit, Credit Facility, Maximum Borrowing Capacity	$ 3,000
Maturity Period, Line of Credit	5 years
Number of banks that comprise revolving bank credit facility (banks) | banks	23
Maximum percentage of indebtedness to total net capital bank covenant	55.00%
Five Year $3.0 Billion Credit Facility [Member] | Minimum [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate During Period	1.60%
Five Year $3.0 Billion Credit Facility [Member] | Maximum [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate During Period	2.20%
Three Year $2.0 Billion Credit Facility [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long-term Line of Credit	$ 0
Line of Credit, Credit Facility, Maximum Borrowing Capacity	$ 2,000
Maturity Period, Line of Credit	3 years
Number of banks that comprise revolving bank credit facility (banks)	23
Maximum percentage of indebtedness to total net capital bank covenant	55.00%
Three Year $2.0 Billion Credit Facility [Member] | Minimum [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate During Period	1.60%
Three Year $2.0 Billion Credit Facility [Member] | Maximum [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate During Period	2.20%
364 Day $1.0 Billion Credit Facility [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long-term Line of Credit	$ 0
Line of Credit, Credit Facility, Maximum Borrowing Capacity	$ 1,000
Maturity Period, Line of Credit	364 days
Number of banks that comprise revolving bank credit facility (banks)	23
Maximum percentage of indebtedness to total net capital bank covenant	55.00%
364 Day $1.0 Billion Credit Facility [Member] | Minimum [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate During Period	1.60%
364 Day $1.0 Billion Credit Facility [Member] | Maximum [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate During Period	2.20%
Subsidiaries [Member]
Debt Instrument [Line Items]
Other Long-term Debt	$ 200	$ 164
Other Long-term Debt, Current	$ 80	$ 47

Commercial Paper and Long-Ter65

Commercial Paper and Long-Term Debt (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Par Value	$ 33,022	$ 31,972
Carrying Value	32,770	31,801
Fair Value	34,728	33,278
Commercial Paper [Member]
Debt Instrument [Line Items]
Par Value	3,633	3,987
Commercial Paper	3,633	3,987	[1]
Debt and other financing obligations	3,633	3,987
Floating-rate Term Loan Due July 2016 [Member]
Debt Instrument [Line Items]
Par Value	0	1,500
Commercial Paper	0	1,500	[1]
Debt and other financing obligations	$ 0	1,500
5.375% Notes Due March 2016 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.375%
Par Value	$ 0	601
Carrying Value	0	605	[1]
Fair Value	$ 0	606
1.875% Notes Due November 2016 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.875%
Par Value	$ 0	400
Carrying Value	0	400	[1]
Fair Value	$ 0	403
5.360% Notes Due November 2016 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.36%
Par Value	$ 0	95
Carrying Value	0	95	[1]
Fair Value	0	98
Floating-rate Notes Due January 2017 [Member]
Debt Instrument [Line Items]
Par Value	750	750
Carrying Value	750	749	[1]
Fair Value	$ 750	751
6.000% Notes Due June 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.00%
Par Value	$ 441	441
Carrying Value	446	458	[1]
Fair Value	$ 450	469
1.450% Notes Due July 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.45%
Par Value	$ 750	750
Carrying Value	750	749	[1]
Fair Value	$ 751	750
1.400% Notes Due October 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.40%
Par Value	$ 625	625
Carrying Value	624	624	[1]
Fair Value	$ 626	624
6.000% Notes Due November 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.00%
Par Value	$ 156	156
Carrying Value	159	162	[1]
Fair Value	$ 163	168
1.400% Notes Due December 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.40%
Par Value	$ 750	750
Carrying Value	751	751	[1]
Fair Value	$ 750	748
6.000% Notes Due February 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.00%
Par Value	$ 1,100	1,100
Carrying Value	1,107	1,114	[1]
Fair Value	$ 1,153	1,196
1.900% Notes Due July 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.90%
Par Value	$ 1,500	1,500
Carrying Value	1,496	1,494	[1]
Fair Value	$ 1,507	1,505
1.700% Notes due February 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.70%
Par Value	$ 750	0
Carrying Value	748	0	[1]
Fair Value	$ 748	0
1.625% Notes Due March 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.625%
Par Value	$ 500	500
Carrying Value	501	502	[1]
Fair Value	$ 498	494
2.300% Notes Due December 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.30%
Par Value	$ 500	500
Carrying Value	498	499	[1]
Fair Value	$ 504	502
2.700% Notes Due July 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.70%
Par Value	$ 1,500	1,500
Carrying Value	1,495	1,493	[1]
Fair Value	$ 1,523	1,516
3.875% Notes Due October 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.875%
Par Value	$ 450	450
Carrying Value	450	452	[1]
Fair Value	$ 474	476
4.700% Notes Due February 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.70%
Par Value	$ 400	400
Carrying Value	409	413	[1]
Fair Value	$ 433	438
2.125% notes due March 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.125%
Par Value	$ 750	0
Carrying Value	745	0	[1]
Fair Value	$ 741	0
3.375% Notes Due November 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.375%
Par Value	$ 500	500
Carrying Value	497	500	[1]
Fair Value	$ 519	517
2.875% Notes Due December 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.875%
Par Value	$ 750	750
Carrying Value	748	753	[1]
Fair Value	$ 760	760
2.875% Notes Due March 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.875%
Par Value	$ 1,100	1,100
Carrying Value	1,057	1,059	[1]
Fair Value	$ 1,114	1,099
3.350% Notes Due July 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.35%
Par Value	$ 1,000	1,000
Carrying Value	995	994	[1]
Fair Value	$ 1,030	1,023
0.000% Notes Due November 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	0.00%
Par Value	$ 15	15
Carrying Value	11	10	[1]
Fair Value	$ 12	11
2.750% Notes Due February 2023 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.75%
Par Value	$ 625	625
Carrying Value	609	611	[1]
Fair Value	$ 622	613
2.875% Notes Due March 2023 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.875%
Par Value	$ 750	750
Carrying Value	771	781	[1]
Fair Value	$ 753	742
3.750% Notes Due July 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.75%
Par Value	$ 2,000	2,000
Carrying Value	1,986	1,985	[1]
Fair Value	$ 2,070	2,062
3.100% notes due March 2026 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.10%
Par Value	$ 1,000	0
Carrying Value	994	0	[1]
Fair Value	$ 986	0
3.450% notes due January 2027 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.45%
Par Value	$ 750	0
Carrying Value	745	0	[1]
Fair Value	$ 762	0
4.625% Notes Due July 2035 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.625%
Par Value	$ 1,000	1,000
Carrying Value	991	991	[1]
Fair Value	$ 1,090	1,038
5.800% Notes Due March 2036 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.80%
Par Value	$ 850	850
Carrying Value	837	838	[1]
Fair Value	$ 1,034	1,003
6.500% Notes Due June 2037 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.50%
Par Value	$ 500	500
Carrying Value	491	492	[1]
Fair Value	$ 643	628
6.625% Notes Due November 2037 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.625%
Par Value	$ 650	650
Carrying Value	640	641	[1]
Fair Value	$ 850	829
6.875% Notes Due Februray 2038 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.875%
Par Value	$ 1,100	1,100
Carrying Value	1,075	1,076	[1]
Fair Value	$ 1,497	1,439
5.700% Notes Due October 2040 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.70%
Par Value	$ 300	300
Carrying Value	296	296	[1]
Fair Value	$ 366	348
5.950% Notes Due Februrary 2041 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.95%
Par Value	$ 350	350
Carrying Value	345	345	[1]
Fair Value	$ 437	416
4.625% Notes Due November 2041 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.625%
Par Value	$ 600	600
Carrying Value	588	588	[1]
Fair Value	$ 634	609
4.375% Notes Due March 2042 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.375%
Par Value	$ 502	502
Carrying Value	483	483	[1]
Fair Value	$ 509	493
3.950% Notes Due October 2042 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.95%
Par Value	$ 625	625
Carrying Value	606	606	[1]
Fair Value	$ 609	582
4.250% Notes Due March 2043 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.25%
Par Value	$ 750	750
Carrying Value	734	734	[1]
Fair Value	$ 765	728
4.750% Notes Due July 2045 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.75%
Par Value	$ 2,000	2,000
Carrying Value	1,972	1,971	[1]
Fair Value	$ 2,203	2,107
4.200% notes due January 2047 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.20%
Par Value	$ 750	0
Carrying Value	737	0	[1]
Fair Value	$ 759	$ 0
[1]	In the first quarter of 2016, the Company adopted ASU 2015-03, retrospectively as required. See Note 2 for more information on the adoption of ASU 2015-03.

Commercial Paper and Long-Ter66

Commercial Paper and Long-Term Debt Maturities of commercial paper and long-term debt (Details) $ in Millions	Dec. 31, 2016USD ($)
Debt Instrument [Line Items]
2,017	$ 7,185
2,018	2,622
2,019	1,769
2,020	1,955
2,021	2,407
Thereafter	$ 17,284

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Contingency [Line Items]
Operating Loss Carryforwards	$ 74
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	11	$ 11	$ 6
Undistributed Earnings of Foreign Subsidiaries	717
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	70	$ 59
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	$ 197
Federal [Member]
Income Tax Contingency [Line Items]
Open Tax Year	2,016
Federal [Member] | Earliest Tax Year [Member]
Income Tax Contingency [Line Items]
Net Operating Loss Carryforwards, Expiration Date	Jan. 1, 2021
Federal [Member] | Latest Tax Year [Member]
Income Tax Contingency [Line Items]
Net Operating Loss Carryforwards, Expiration Date	Dec. 31, 2036
State [Member] | Earliest Tax Year [Member]
Income Tax Contingency [Line Items]
Net Operating Loss Carryforwards, Expiration Date	Jan. 1, 2017
Open Tax Year	2,010
State [Member] | Latest Tax Year [Member]
Income Tax Contingency [Line Items]
Net Operating Loss Carryforwards, Expiration Date	Dec. 31, 2036
Open Tax Year	2,016

Income Taxes Reconciliation of

Income Taxes Reconciliation of Provision for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current Provision:
Federal	$ 4,397	$ 4,155	$ 3,883
State and local	312	281	271
Total current provision	4,709	4,436	4,154
Deferred provision (benefit)	81	(73)	(117)
Total provision for income taxes	$ 4,790	$ 4,363	$ 4,037

Income Tax Reconciliation of th

Income Tax Reconciliation of the tax provision at the U.S. Federal Statutory Rate (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Contingency [Line Items]
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount	$ 4,152	$ 3,581	$ 3,380
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	35.00%	35.00%	35.00%
Nonrefundable Industry Tax Expense	$ 645	$ 627	$ 469
Effective Income Tax Rate Nondeductible Industry Tax	5.40%	6.10%	4.80%
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	$ 205	$ 145	$ 154
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent	1.70%	1.40%	1.60%
Effective Income Tax Rate Reconciliation, Tax Exempt Income, Amount	$ (158)	$ 0	$ 0
Effective Income Tax Rate Reconciliation, Tax Exempt Income, Percent	(1.30%)	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount	$ 128	$ 103	$ 96
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent	1.10%	1.00%	1.00%
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	$ (182)	$ (93)	$ (62)
Effective Income Tax Rate Reconciliation, Other Adjustments, Percent	(1.50%)	(0.90%)	(0.60%)
Total provision for income taxes	$ 4,790	$ 4,363	$ 4,037
Effective Income Tax Rate Reconciliation, Percent	40.40%	42.60%	41.80%

Income Taxes Components of Defe

Income Taxes Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Deferred income tax assets:
Accrued expenses and allowances	$ 820	$ 739
U.S. federal and state net operating loss carryforwards	147	139
Share-based compensation	126	124
Nondeductible liabilities	236	205
Medical costs payable and other current liabilities	95	71
Non-U.S. tax loss carryforwards	434	244
Net unrealized losses on investments	55	0
Other-domestic	194	214
Other-non-U.S.	175	130
Subtotal	2,282	1,866
Less: valuation allowances	(55)	(44)
Total deferred income tax assets	2,227	1,822
Deferred income tax liabilities:
U.S. federal and state intangible assets	(3,055)	(2,951)
Non-U.S. goodwill and intangible assets	(584)	(397)
Capitalized software	(707)	(574)
Net unrealized gains on investments	0	(34)
Depreciation and amortization	(332)	(312)
Prepaid expenses	(228)	(205)
Other-non-U.S.	(82)	(76)
Total deferred income tax liabilities	(4,988)	(4,549)
Net deferred income tax liabilities	$ (2,761)	$ (2,727)

Income Taxes Reconciliation o71

Income Taxes Reconciliation of the beginning and ending amount of unrecognized tax benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Contingency [Line Items]
Gross unrecognized tax benefits, beginning of period	$ 224	$ 92	$ 89
Current year tax positions	37	0	0
Prior year tax positions, gross increases	24	55	4
Acquired Reserves	0	89	0
Prior year tax positions, gross decreases	(4)	(2)	0
Settlements	(6)	(1)	0
Statute of limitations lapses	(12)	(9)	(1)
Gross unrecognized tax benefits, end of period	$ 263	$ 224	$ 92

Shareholders' Equity (Details)

Shareholders' Equity (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2014	Dec. 31, 2013
Shareholders' Equity Disclosure [Line Items]
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	$ 3,900	$ 4,400
Cash and cash equivalents	10,430	10,923			$ 7,495	$ 7,276
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	17,900
Statutory Accounting Practices, Statutory Capital and Surplus Required	$ 10,500
Cash Dividend Annual Rate Per Share			$ 2.50	$ 2
Stock Repurchase Program, Number of Shares Authorized to be Repurchased	100
General Corporate Use [Member]
Shareholders' Equity Disclosure [Line Items]
Cash and cash equivalents	$ 700
Extraordinary Dividends [Member]
Shareholders' Equity Disclosure [Line Items]
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	$ 3,300	$ 1,500

Shareholders' Equity Share Repu

Shareholders' Equity Share Repurchases (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Stockholders' Equity [Abstract]
Common shares repurchases, shares	10,000,000	11,000,000
Common share repurchases, average price per share	$ 128.97	$ 112.45
Common share repurchases, aggregate cost	$ 1,280	$ 1,200	$ 4,008
Board authorized shares remaining	51,000,000	61,000,000

Share-Based Compensation Narrat

Share-Based Compensation Narrative (Details) - USD ($) shares in Millions, $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	68
Deferred Compensation, Recorded Liability	$ 672	$ 553
Employee Stock Purchase Plan (ESPP) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	10

Share-Based Compensation (Stock

Share-Based Compensation (Stock Option and SAR Activity) (Details) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at the beginning of the period | shares	34
Granted, Shares | shares	11
Exercised, Shares | shares	(8)
Forfeitures, Shares | shares	(1)
Outstanding at the end of the period | shares	36
Exercisable at end of period, Shares | shares	14
Vested and expected to vest end of period, Shares | shares	35
Outstanding at beginning of period, Weighted-Average Exercise Price | $ / shares	$ 68
Granted, Weighted-Average Exercise Price | $ / shares	113
Exercised, Weighted-Average Exercise Price | $ / shares	57
Forfeitures, Weighted Average Exercise Price | $ / shares	103
Outstanding at end of period, Weighted-Average Exercise Price | $ / shares	84
Exercisable at end of period, Weighted-Average Exercise Price | $ / shares	56
Vested and expected to vest end of period, Weighted-Average Exercise Price | $ / shares	$ 83
Outstanding at end of period, Weighted Average Remaining Contractual Term (in years)	6 years 7 months 9 days
Exercisable at end of period, Weighted Average Remaining Contractual Term (in years)	4 years
Vested and expected to vest end of period, Weighted Average Remaining Contractual Term (in years)	6 years 7 months 9 days
Outstanding at end of period, Aggregate Intrinsic Value | $	$ 2,758
Exercisable at end of period, Aggregate Intrinsic Value | $	1,458
Vested and expected to vest end of period, Aggregate Intrinsic Value | $	$ 2,704

Share-Based Compensation (Restr

Share-Based Compensation (Restricted Share Activity) (Details) - Restricted Stock [Member] shares in Millions	12 Months Ended
	Dec. 31, 2016$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Nonvested at beginning of period, Shares | shares	7
Granted, Shares | shares	3
Vested | shares	(3)
Nonvested at end of period, Shares | shares	7
Nonvested at beginning of period, Weighted-Average Grant Date Fair Value per Share | $ / shares	$ 82
Weighted-average grant date fair value (per share) | $ / shares	115
Vested, Weighted Average Grant Date Fair Value | $ / shares	76
Nonvested at end of period, Weighted-Average Grant Date Fair Value per Share | $ / shares	$ 96

Share-Based Compensation Other

Share-Based Compensation Other Share-Based Compensation Data (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense, before tax	$ 485	$ 406	$ 364
Share-based compensation expense, net of tax effects	417	348	314
Income tax benefit realized from share-based award exercises	236	$ 247	$ 231
Unrecognized compensation expense related to share awards	$ 516
Weighted-average years to recognize compensation expense	1 year 3 months 18 days
Stock Options and SARs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value of shares granted, per share	$ 20	$ 22	$ 22
Total intrinsic value of stock options and SARs exercised	$ 595	$ 482	$ 526
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value (per share)	$ 115	$ 110	$ 71
Total fair value of restricted shares vested	$ 274	$ 460	$ 437
Employee Stock Purchase Plan (ESPP) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares purchased	2	2	2

Share-Based Compensation (Share

Share-Based Compensation (Share-Based Compensation Principal Fair Value Assumptions) (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	1.80%
Forfeiture rate	5.00%	5.00%	5.00%
Expected Life in years			5 years 4 months 24 days
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.20%	1.60%	1.70%
Expected Volatility	20.80%	22.30%	24.10%
Expected dividend yield		1.40%	1.60%
Expected Life in years	5 years 7 months 9 days	5 years 6 months
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.40%	1.70%	1.80%
Expected Volatility	22.50%	24.10%	39.60%
Expected dividend yield		1.70%	1.90%
Expected Life in years	5 years 10 months 29 days	6 years 1 month 6 days

Commitments and Contingencies79

Commitments and Contingencies (Details) - USD ($) $ in Millions	Dec. 31, 2016	Jun. 09, 2014	Jan. 25, 2008	Aug. 31, 2013	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Loss Contingencies [Line Items]
Undrawn Letters Of Credit	$ 28				$ 28
Operating Leases, Rent Expense					608	$ 555	$ 449
Surety Bonds Outstanding	1,200				1,200
California Claims Processing Matter [Member]
Loss Contingencies [Line Items]
Estimated Largest Penalty Ever Issued By Cdi	8				$ 8
Loss Contingency, Damages Sought, Value			$ 325
Penn Treaty [Member]
Loss Contingencies [Line Items]
Loss Contingency, Discounted Amount of Insurance-related Assessment Liability	$ 350
California Administrative Law Judge [Member] | California Claims Processing Matter [Member] | Judicial Ruling [Member]
Loss Contingencies [Line Items]
Loss Contingency, Damages Awarded, Value				$ 11.5
California Insurance Commissioner [Member] | California Claims Processing Matter [Member] | Judicial Ruling [Member]
Loss Contingencies [Line Items]
Loss Contingency, Damages Awarded, Value		$ 174

Commitments and Contingencies F

Commitments and Contingencies Future Lease Payments (Details) $ in Millions	Dec. 31, 2016USD ($)
Operating Leased Assets [Line Items]
2,017	$ 453
2,018	416
2,019	355
2,020	314
2,021	273
Thereafter	$ 499

Segment Financial Information81

Segment Financial Information (Narrative) (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement [Line Items]
Number of Reportable Segments	4
UNITED STATES
Statement [Line Items]
Disclosure on Geographic Areas Percentage of Revenue from External Customers	97.00%	96.00%	95.00%
Disclosure on Geographic Areas Percentage of Long Lived Assets	75.00%	81.00%
Revenues [Member] | CMS Subsidies [Member]
Statement [Line Items]
Concentration Risk, Percentage	25.00%	26.00%	29.00%

Segment Financial Information82

Segment Financial Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014
Statement [Line Items]
Premiums, revenues - external customers	$ 144,118	$ 127,163		$ 115,302
Products, revenues - external customers	26,658	17,312		4,242
Services, revenues - external customers	13,236	11,922		10,151
Investment and other income	828	710		779
Total revenues	184,840	157,107		130,474
Earnings from operations	12,930	11,021		10,274
Interest expense	(1,067)	(790)		(618)
Earnings before income taxes	11,863	10,231		9,656
Total assets	122,810	111,254	[1]	86,300	[1]
Purchases of property, equipment and capitalized software	1,705	1,556		1,525
Depreciation and amortization	2,055	1,693		1,478
Optum [Member]
Statement [Line Items]
Investment and other income	217	156		145
Total revenues	83,593	67,604		47,746
Earnings from operations	5,623	4,267		3,282
Interest expense	0	0		0
Earnings before income taxes	5,623	4,267		3,282
Total assets	56,739	49,779	[1]	24,734	[1]
Purchases of property, equipment and capitalized software	1,065	903		752
Depreciation and amortization	1,331	975		706
External Customers [Member]
Statement [Line Items]
Premiums, revenues - external customers	144,118	127,163		115,302
Products, revenues - external customers	26,658	17,312		4,242
Services, revenues - external customers	13,236	11,922		10,151
Total revenues	184,012	156,397		129,695
External Customers [Member] | Optum [Member]
Statement [Line Items]
Premiums, revenues - external customers	3,663	3,152		2,657
Products, revenues - external customers	26,657	17,310		4,239
Services, revenues - external customers	5,722	5,146		3,635
Total revenues	36,042	25,608		10,531
Intersegment [Member]
Statement [Line Items]
Total revenues	0	0		0
Intersegment [Member] | Optum [Member]
Statement [Line Items]
Total revenues	47,334	41,840		37,070
Operating Segments [Member] | UnitedHealthcare [Member]
Statement [Line Items]
Investment and other income	611	554		634
Total revenues	148,581	131,343		119,798
Earnings from operations	7,307	6,754		6,992
Interest expense	0	0		0
Earnings before income taxes	7,307	6,754		6,992
Total assets	70,505	64,212	[1]	62,405	[1]
Purchases of property, equipment and capitalized software	640	653		773
Depreciation and amortization	724	718		772
Operating Segments [Member] | OptumHealth [Member]
Statement [Line Items]
Investment and other income	208	153		144
Total revenues	16,908	13,927		11,032
Earnings from operations	1,428	1,240		1,090
Interest expense	0	0		0
Earnings before income taxes	1,428	1,240		1,090
Total assets	18,656	14,600	[1]	11,148	[1]
Purchases of property, equipment and capitalized software	345	252		212
Depreciation and amortization	297	251		179
Operating Segments [Member] | OptumInsight [Member]
Statement [Line Items]
Investment and other income	1	1		1
Total revenues	7,333	6,196		5,227
Earnings from operations	1,513	1,278		1,002
Interest expense	0	0		0
Earnings before income taxes	1,513	1,278		1,002
Total assets	9,017	8,335	[1]	8,112	[1]
Purchases of property, equipment and capitalized software	571	572		484
Depreciation and amortization	559	492		433
Operating Segments [Member] | OptumRx [Member]
Statement [Line Items]
Investment and other income	8	2		0
Total revenues	60,440	48,272		31,976
Earnings from operations	2,682	1,749		1,190
Interest expense	0	0		0
Earnings before income taxes	2,682	1,749		1,190
Total assets	29,066	26,844	[1]	5,474	[1]
Purchases of property, equipment and capitalized software	149	79		56
Depreciation and amortization	475	232		94
Operating Segments [Member] | External Customers [Member] | UnitedHealthcare [Member]
Statement [Line Items]
Premiums, revenues - external customers	140,455	124,011		112,645
Products, revenues - external customers	1	2		3
Services, revenues - external customers	7,514	6,776		6,516
Total revenues	147,970	130,789		119,164
Operating Segments [Member] | External Customers [Member] | OptumHealth [Member]
Statement [Line Items]
Premiums, revenues - external customers	3,663	3,152		2,657
Products, revenues - external customers	48	31		18
Services, revenues - external customers	2,498	2,375		1,300
Total revenues	6,209	5,558		3,975
Operating Segments [Member] | External Customers [Member] | OptumInsight [Member]
Statement [Line Items]
Premiums, revenues - external customers	0	0		0
Products, revenues - external customers	103	108		96
Services, revenues - external customers	2,670	2,390		2,224
Total revenues	2,773	2,498		2,320
Operating Segments [Member] | External Customers [Member] | OptumRx [Member]
Statement [Line Items]
Premiums, revenues - external customers	0	0		0
Products, revenues - external customers	26,506	17,171		4,125
Services, revenues - external customers	554	381		111
Total revenues	27,060	17,552		4,236
Operating Segments [Member] | Intersegment [Member] | UnitedHealthcare [Member]
Statement [Line Items]
Total revenues	0	0		0
Operating Segments [Member] | Intersegment [Member] | OptumHealth [Member]
Statement [Line Items]
Total revenues	10,491	8,216		6,913
Operating Segments [Member] | Intersegment [Member] | OptumInsight [Member]
Statement [Line Items]
Total revenues	4,559	3,697		2,906
Operating Segments [Member] | Intersegment [Member] | OptumRx [Member]
Statement [Line Items]
Total revenues	33,372	30,718		27,740
Optum Eliminations [Member]
Statement [Line Items]
Investment and other income	0	0		0
Total revenues	(1,088)	(791)		(489)
Earnings from operations	0	0		0
Interest expense	0	0		0
Earnings before income taxes	0	0		0
Total assets	0	0	[1]	0	[1]
Purchases of property, equipment and capitalized software	0	0		0
Depreciation and amortization	0	0		0
Optum Eliminations [Member] | External Customers [Member]
Statement [Line Items]
Premiums, revenues - external customers	0	0		0
Products, revenues - external customers	0	0		0
Services, revenues - external customers	0	0		0
Total revenues	0	0		0
Optum Eliminations [Member] | Intersegment [Member]
Statement [Line Items]
Total revenues	(1,088)	(791)		(489)
Corporate and Eliminations [Member]
Statement [Line Items]
Investment and other income	0	0		0
Total revenues	(47,334)	(41,840)		(37,070)
Earnings from operations	0	0		0
Interest expense	(1,067)	(790)		(618)
Earnings before income taxes	(1,067)	(790)		(618)
Total assets	(4,434)	(2,737)	[1]	(839)	[1]
Purchases of property, equipment and capitalized software	0	0		0
Depreciation and amortization	0	0		0
Corporate and Eliminations [Member] | External Customers [Member]
Statement [Line Items]
Premiums, revenues - external customers	0	0		0
Products, revenues - external customers	0	0		0
Services, revenues - external customers	0	0		0
Total revenues	0	0		0
Corporate and Eliminations [Member] | Intersegment [Member]
Statement [Line Items]
Total revenues	$ (47,334)	$ (41,840)		$ (37,070)
[1]	(a)In the first quarter of 2016, the Company adopted ASU 2015-03, retrospectively as required. See Note 2 for more information on the adoption of ASU 2015-03.

Quarterly Financial Data (Una83

Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues									$ 184,840	$ 157,107	$ 130,474
Operating costs									171,910	146,086	120,200
Earnings from operations									12,930	11,021	10,274
Net earnings									7,073	5,868	5,619
Net earnings attributable to UnitedHealth Group common shareholders									$ 7,017	$ 5,813	$ 5,619
Net earnings per share attributable to UnitedHealth Group common stockholders:
Basic									$ 7.37	$ 6.10	$ 5.78
Diluted									$ 7.25	$ 6.01	$ 5.70
Quarterly Financial Data (Unaudited) [Member]
Revenues	$ 47,535	$ 46,293	$ 46,485	$ 44,527	$ 43,599	$ 41,489	$ 36,263	$ 35,756
Operating costs	44,348	42,713	43,282	41,567	41,131	38,471	33,368	33,116
Earnings from operations	3,187	3,580	3,203	2,960	2,468	3,018	2,895	2,640
Net earnings	1,708	1,978	1,760	1,627	1,252	1,618	1,585	1,413
Net earnings attributable to UnitedHealth Group common shareholders	$ 1,684	$ 1,968	$ 1,754	$ 1,611	$ 1,218	$ 1,597	$ 1,585	$ 1,413
Net earnings per share attributable to UnitedHealth Group common stockholders:
Basic	$ 1.77	$ 2.07	$ 1.84	$ 1.69	$ 1.28	$ 1.68	$ 1.66	$ 1.48
Diluted	$ 1.74	$ 2.03	$ 1.81	$ 1.67	$ 1.26	$ 1.65	$ 1.64	$ 1.46

Schedule I (Details)

Schedule I (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jul. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Financial Statements, Captions [Line Items]
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries		$ 3,900	$ 4,400
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries		3,700	4,800	$ 5,500
Return of capital to parent company		2,143	4,375	0
Payments to Fund Long-term Loans to Related Parties		824	5,064	$ 436
Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Other Long-term Debt		$ 200	$ 164
Catamaran [Member] | Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Payments to Fund Long-term Loans to Related Parties	$ 4,800

Schedule I Condensed Balance Sh

Schedule I Condensed Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 10,430	$ 10,923		$ 7,495		$ 7,276
Total current assets	33,879	31,639
Other assets	3,037	3,118
Total assets	122,810	111,254	[1]	86,300	[1]
Current liabilities:
Accounts payable and accrued liabilities	13,361	11,994
Commercial paper and current maturities of long-term debt	7,193	6,634
Total current liabilities	49,252	42,898
Long-term debt, less current maturities	25,777	25,331
Other liabilities	2,307	1,481
Total liabilities	82,621	75,793
Commitments and contingencies (Note 4)
Shareholders’ equity:
Preferred stock, $0.001 par value - 10 shares authorized; no shares issued or outstanding	0	0
Common stock, $0.01 par value - 3,000 shares authorized; 952 and 953 issued and outstanding	10	10
Additional paid-in capital	0	29
Retained earnings	40,945	37,125
Accumulated other comprehensive loss	(2,681)	(3,334)
Total liabilities and shareholders’ equity	122,810	111,254
Parent Company [Member]
Current assets:
Cash and cash equivalents	180	29		$ 559		$ 822
Short-term notes receivable from subsidiaries	755	0
Other current assets	140	313
Total current assets	1,075	342
Equity in net assets of subsidiaries	60,593	56,316
Long-term notes receivable from subsidiaries	9,912	9,679
Other assets	248	199
Total assets	71,828	66,536
Current liabilities:
Accounts payable and accrued liabilities	452	449
Note payable to subsidiary	280	310
Commercial paper and current maturities of long-term debt	7,113	6,587
Total current liabilities	7,845	7,346
Long-term debt, less current maturities	25,657	25,215
Other liabilities	52	145
Total liabilities	33,554	32,706
Shareholders’ equity:
Preferred stock, $0.001 par value - 10 shares authorized; no shares issued or outstanding	0	0
Common stock, $0.01 par value - 3,000 shares authorized; 952 and 953 issued and outstanding	10	10
Additional paid-in capital	0	29
Retained earnings	40,945	37,125
Accumulated other comprehensive loss	(2,681)	(3,334)
Total UnitedHealth Group shareholders’ equity	38,274	33,830
Total liabilities and shareholders’ equity	$ 71,828	$ 66,536
[1]	(a)In the first quarter of 2016, the Company adopted ASU 2015-03, retrospectively as required. See Note 2 for more information on the adoption of ASU 2015-03.

Schedule I Balance Sheet Docume

Schedule I Balance Sheet Document (Details) - $ / shares shares in Millions	Dec. 31, 2016	Dec. 31, 2015
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	3,000	3,000
Common stock, shares issued	952	953
Common Stock, shares outstanding	952	953
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	10	10
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Parent Company [Member]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	3,000	3,000
Common stock, shares issued	952	953
Common Stock, shares outstanding	952	953
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	10	10
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0

Schedule I Condensed Statement

Schedule I Condensed Statement of Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues:
Investment and other income	$ 828	$ 710	$ 779
Total revenues	184,840	157,107	130,474
Operating costs:
Interest expense	1,067	790	618
Total operating costs	171,910	146,086	120,200
Loss before income taxes	11,863	10,231	9,656
Benefit for income taxes	4,790	4,363	4,037
Net earnings	7,017	5,813	5,619
Other comprehensive income (loss)	653	(1,942)	(484)
Comprehensive income	7,670	3,871	5,135
Parent Company [Member]
Revenues:
Investment and other income	522	396	293
Total revenues	522	396	293
Operating costs:
Operating costs	(22)	(17)	1
Interest expense	995	717	554
Total operating costs	973	700	555
Loss before income taxes	(451)	(304)	(262)
Benefit for income taxes	165	111	96
Loss of parent company	(286)	(193)	(166)
Equity in undistributed income of subsidiaries	7,303	6,006	5,785
Net earnings	7,017	5,813	5,619
Other comprehensive income (loss)	653	(1,942)	(484)
Comprehensive income	$ 7,670	$ 3,871	$ 5,135

Schedule I Statement of Cash Fl

Schedule I Statement of Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities
Cash flows from operating activities	$ 9,795	$ 9,740	$ 8,051
Investing activities
Cash paid for acquisitions	(1,760)	(16,164)	(1,923)
Other, net	(37)	144	(115)
Cash flows used for investing activities	(9,355)	(18,395)	(2,534)
Financing activities
Common stock repurchases	(1,280)	(1,200)	(4,008)
Proceeds from common stock issuances	429	402	462
(Repayments of) proceeds from commercial paper, net	(382)	3,666	(794)
Proceeds from issuance of long-term debt	3,968	11,982	1,997
Repayments of long-term debt	(2,596)	(1,041)	(812)
Other, net	(324)	(434)	(138)
Cash flows (used for) from financing activities	(1,011)	12,239	(5,293)
Increase (decrease) in cash and cash equivalents	(493)	3,428	219
Cash and cash equivalents, beginning of period	10,923	7,495	7,276
Cash and cash equivalents, end of period	10,430	10,923	7,495
Supplemental cash flow disclosures
Cash paid for interest	1,055	639	644
Cash paid for income taxes	4,726	4,401	4,024
Parent Company [Member]
Operating activities
Cash flows from operating activities	4,294	1,727	7,445
Investing activities
Issuance of notes to subsidiaries	(824)	(5,064)	(436)
Cash paid for acquisitions	(2,292)	(12,270)	(1,852)
Return of capital to parent company	2,143	4,375	0
Capital contributions to subsidiaries	(765)	(1,109)	(704)
Other, net	168	140	(9)
Cash flows used for investing activities	(1,570)	(13,928)	(3,001)
Financing activities
Common stock repurchases	(1,280)	(1,200)	(4,008)
Proceeds from common stock issuances	429	402	462
Cash dividends paid	(2,261)	(1,786)	(1,362)
(Repayments of) proceeds from commercial paper, net	(382)	3,666	(794)
Proceeds from issuance of long-term debt	3,968	11,982	1,997
Repayments of long-term debt	(2,596)	(1,041)	(812)
Other, net	(451)	(352)	(190)
Cash flows (used for) from financing activities	(2,573)	11,671	(4,707)
Increase (decrease) in cash and cash equivalents	151	(530)	(263)
Cash and cash equivalents, beginning of period	29	559	822
Cash and cash equivalents, end of period	180	29	559
Supplemental cash flow disclosures
Cash paid for interest	974	573	578
Cash paid for income taxes	$ 4,557	$ 4,294	$ 4,028

Schedule I Maturities of Commer

Schedule I Maturities of Commercial Paper and Long-Term Debt (Details) $ in Millions	Dec. 31, 2016USD ($)
Debt Instrument [Line Items]
2,017	$ 7,185
2,018	2,622
2,019	1,769
2,020	1,955
2,021	2,407
Thereafter	17,284
Parent Company [Member]
Debt Instrument [Line Items]
2,017	7,105
2,018	2,600
2,019	1,750
2,020	1,950
2,021	2,400
Thereafter	$ 17,217