Elevance Health (ELV) 10-Q 21 Jul 21 2021 Q2 Quarterly report Financial data

Document And Entity Information

Document And Entity Information Document - shares	6 Months Ended
	Jun. 30, 2021	Jul. 15, 2021
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2021
Document Transition Report	false
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-31
Entity Central Index Key	0001156039
Entity File Number	001-16751
Entity Registrant Name	ANTHEM, INC.
Entity Incorporation, State or Country Code	IN
Entity Tax Identification Number	35-2145715
Entity Address, Address Line One	220 Virginia Avenue
Entity Address, City or Town	Indianapolis
Entity Address, State or Province	IN
Entity Address, Postal Zip Code	46204
City Area Code	800
Local Phone Number	331-1476
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	ANTM
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		243,815,480

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 5,258	$ 5,741
Fixed maturity securities (amortized cost of $24,871 and $22,222; allowance for credit losses of $6 and $7)	25,848	23,433
Equity securities	1,746	1,559
Premium receivables	5,834	5,279
Self-funded receivables	3,605	2,849
Other receivables	3,246	2,830
Other current assets	4,701	4,060
Total current assets	50,238	45,751
Long-term investments:
Fixed maturity securities (amortized cost of $558 and $532; allowance for credit losses of $0 and $0)	581	562
Other invested assets	4,917	4,285
Property and equipment, net	3,733	3,483
Goodwill	24,399	21,691
Other intangible assets	10,540	9,405
Other noncurrent assets	1,689	1,438
Total assets	96,097	86,615
Current Liabilities:
Medical claims payable	13,076	11,359
Other policyholder liabilities	5,285	4,590
Unearned income	1,081	1,259
Accounts payable and accrued expenses	5,598	5,493
Short-term borrowings	175	0
Current portion of long-term debt	849	700
Other current liabilities	7,730	6,052
Total current liabilities	33,794	29,453
Long-term debt, less current portion	22,217	19,335
Reserves for future policy benefits, noncurrent	774	794
Deferred tax liabilities, net	2,397	2,019
Other noncurrent liabilities	1,869	1,815
Total liabilities	61,051	53,416
Commitments and contingencies – Note 11
Shareholders' equity
Preferred stock, without par value, shares authorized – 100,000,000; shares issued and outstanding – none	0	0
Common stock, par value $0.01, shares authorized – 900,000,000; shares issued and outstanding – 243,922,167 and 245,401,430	2	3
Additional paid-in capital	9,109	9,244
Retained earnings	25,874	23,802
Accumulated other comprehensive (loss) income	(17)	150
Total shareholders' equity	34,968	33,199
Noncontrolling interests	78	0
Total equity	35,046	33,199
Total liabilities and shareholders' equity	$ 96,097	$ 86,615

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Available-for-sale fixed maturity securities investments, current, amortized cost	$ 24,871	$ 22,222
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss	6	7
Available-for-sale fixed maturity securities investments, long-term, amortized cost	$ 558	$ 532
Preferred stock, par value	$ 0	$ 0
Preferred stock, shares authorized	100,000,000	100,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	900,000,000	900,000,000
Common stock, shares issued	243,922,167	245,401,430
Common stock, shares outstanding	243,922,167	245,401,430

Consolidated Statements Of Inco

Consolidated Statements Of Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenues
Premiums	$ 28,533	$ 25,092	$ 56,209	$ 50,609
Product revenue	3,042	2,543	5,779	4,887
Administrative fees and other revenue	1,704	1,543	3,389	3,130
Total operating revenue	33,279	29,178	65,377	58,626
Net investment income	400	57	691	311
Net realized gains (losses) on financial instruments	172	29	168	(52)
Total revenues	33,851	29,264	66,236	58,885
Expenses
Benefit expense	24,763	19,547	48,462	41,036
Cost of products sold	2,614	2,225	4,927	4,209
Selling, general and administrative expense	3,821	4,046	7,746	7,827
Interest expense	205	201	397	395
Amortization of other intangible assets	90	93	170	176
Loss on extinguishment of debt	5	3	5	4
Total expenses	31,498	26,115	61,707	53,647
Income before income tax expense	2,353	3,149	4,529	5,238
Income tax expense	552	873	1,061	1,439
Net income	1,801	2,276	3,468	3,799
Net income attributable to noncontrolling interests	(8)	0	(10)	0
Shareholders’ net income	$ 1,793	$ 2,276	$ 3,458	$ 3,799
Shareholders’ net income per share
Basic net income per share	$ 7.33	$ 9.02	$ 14.13	$ 15.06
Diluted net income per share	7.25	8.91	13.95	14.85
Dividends per share	$ 1.13	$ 0.95	$ 2.26	$ 1.90

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 1,801	$ 2,276	$ 3,468	$ 3,799
Other comprehensive income (loss), net of tax:
Change in net unrealized losses/gains on investments	175	730	(187)	41
Change in non-credit component of impairment losses on investments	1	10	2	(22)
Change in net unrealized gains/losses on cash flow hedges	2	3	6	6
Change in net periodic pension and postretirement costs	8	10	18	17
Foreign currency translation adjustments	(6)	1	(6)	0
Other comprehensive income (loss)	180	754	(167)	42
Net income attributable to noncontrolling interests	(8)	0	(10)	0
Other comprehensive income attributable to noncontrolling interests	(2)	0	0	0
Total shareholders’ comprehensive income	$ 1,971	$ 3,030	$ 3,291	$ 3,841

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Operating activities
Net income	$ 3,468	$ 3,799
Adjustments to reconcile net income to net cash provided by operating activities:
Net realized (gains) losses on financial instruments	(168)	52
Depreciation and amortization	591	556
Deferred income taxes	(8)	60
Share-based compensation	133	134
Changes in operating assets and liabilities:
Receivables, net	(1,632)	(313)
Other invested assets	(44)	24
Other assets	(247)	(486)
Policy liabilities	1,912	1,024
Unearned income	(180)	(110)
Accounts Payable and Other Operating Liabilities	560	1,868
Income taxes	106	1,313
Other, net	(303)	104
Net cash provided by operating activities	4,188	8,025
Investing activities
Purchases of investments	(11,221)	(11,135)
Proceeds from sale of investments	6,345	4,724
Maturities, calls and redemptions from investments	2,246	1,836
Changes in securities lending collateral	(642)	(764)
Purchases of subsidiaries, net of cash acquired	(3,442)	(1,906)
Purchases of property and equipment	(489)	(437)
Other, net	(29)	(36)
Net cash used in investing activities	(7,232)	(7,718)
Financing activities
Net proceeds (repayments of) from commercial paper borrowings	300	(400)
Proceeds from long-term borrowings	3,462	2,484
Repayments of long-term borrowings	(952)	(155)
Proceeds from short-term borrowings	175	820
Repayments of short-term borrowings	0	(1,520)
Changes in securities lending payable	642	764
Repurchase and retirement of common stock	(927)	(584)
Cash dividends	(555)	(482)
Proceeds from issuance of common stock under employee stock plans	141	92
Taxes paid through withholding of common stock under employee stock plans	(93)	(111)
Other, net	375	(124)
Net cash provided by financing activities	2,568	784
Effect of foreign exchange rates on cash and cash equivalents	(7)	0
Change in cash and cash equivalents	(483)	1,091
Cash and cash equivalents at beginning of period	5,741	4,937
Cash and cash equivalents at end of period	$ 5,258	$ 6,028

Consolidated Statements Of Shar

Consolidated Statements Of Shareholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjusted Balance	Cumulative Effect, Period of Adoption, Adjustment	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Retained Earnings [Member]Cumulative Effect, Period of Adoption, Adjusted Balance	Retained Earnings [Member]Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive (Loss) Income [Member]	Noncontrolling Interest [Member]
Balance (in shares), Beginning at Dec. 31, 2019				252.9
Total shareholders' equity, Beginning Balance at Dec. 31, 2019				$ 3	$ 9,448	$ 22,573	$ 22,538		$ (296)
Total shareholders' equity, Beginning Balance (Accounting Standards Update 2016-13) at Dec. 31, 2019								$ (35)
Total equity, Beginning Balance at Dec. 31, 2019	$ 31,728	$ 31,693
Total equity, Beginning Balance (Accounting Standards Update 2016-13) at Dec. 31, 2019			$ (35)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shareholders' net income						1,523
Shareholders' other comprehensive income (loss)									(712)
Repurchase and retirement of common stock	(529)				(71)	(458)
Repurchase and retirement of common stock, shares				(1.9)
Dividends and dividend equivalents	(243)					(243)
Issuance of common stock under employee stock plans, net of related tax benefits, Shares				1
Issuance of common stock under employee stock plans, net of related tax benefits	3				3
Convertible debenture repurchases and conversions	(42)				(42)
Net income	1,523
Other Comprehensive Income (Loss), Net of Tax	(712)
Balance (in shares), Ending at Mar. 31, 2020				252
Total shareholders' equity, Ending Balance at Mar. 31, 2020				$ 3	9,338	23,360			(1,008)
Total equity, Ending Balance at Mar. 31, 2020	31,693
Balance (in shares), Beginning at Dec. 31, 2019				252.9
Total shareholders' equity, Beginning Balance at Dec. 31, 2019				$ 3	9,448	22,573	$ 22,538		(296)
Total shareholders' equity, Beginning Balance (Accounting Standards Update 2016-13) at Dec. 31, 2019								$ (35)
Total equity, Beginning Balance at Dec. 31, 2019	31,728	$ 31,693
Total equity, Beginning Balance (Accounting Standards Update 2016-13) at Dec. 31, 2019			$ (35)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shareholders' net income	3,799
Shareholders' other comprehensive income (loss)	42
Net income attributable to noncontrolling interests	0
Other comprehensive income attributable to noncontrolling interests	0
Repurchase and retirement of common stock	$ (584)
Repurchase and retirement of common stock, shares	(2.1)
Net income	$ 3,799
Other Comprehensive Income (Loss), Net of Tax	42
Balance (in shares), Ending at Jun. 30, 2020				252.1
Total shareholders' equity, Ending Balance at Jun. 30, 2020				$ 3	9,360	25,346			(254)
Total equity, Ending Balance at Jun. 30, 2020	34,455
Balance (in shares), Beginning at Mar. 31, 2020				252
Total shareholders' equity, Beginning Balance at Mar. 31, 2020				$ 3	9,338	23,360			(1,008)
Total equity, Beginning Balance at Mar. 31, 2020	31,693
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shareholders' net income	2,276					2,276
Shareholders' other comprehensive income (loss)	754								754
Net income attributable to noncontrolling interests	0
Other comprehensive income attributable to noncontrolling interests	0
Repurchase and retirement of common stock	(55)			$ 0	(9)	(46)
Repurchase and retirement of common stock, shares				(0.2)
Dividends and dividend equivalents	(244)					(244)
Issuance of common stock under employee stock plans, net of related tax benefits, Shares				0.3
Issuance of common stock under employee stock plans, net of related tax benefits	113				113
Convertible debenture repurchases and conversions	(82)				(82)
Net income	2,276
Other Comprehensive Income (Loss), Net of Tax	754
Balance (in shares), Ending at Jun. 30, 2020				252.1
Total shareholders' equity, Ending Balance at Jun. 30, 2020				$ 3	9,360	25,346			(254)
Total equity, Ending Balance at Jun. 30, 2020	34,455
Balance (in shares), Beginning at Dec. 31, 2020				245.4
Total shareholders' equity, Beginning Balance at Dec. 31, 2020	33,199			$ 3	9,244	23,802			150
Noncontrolling interests, Beginning Balance at Dec. 31, 2020	0									$ 0
Total equity, Beginning Balance at Dec. 31, 2020	33,199
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shareholders' net income						1,665
Shareholders' other comprehensive income (loss)									(345)
Net income attributable to noncontrolling interests										2
Other comprehensive income attributable to noncontrolling interests										(2)
Noncontrolling interests adjustment	65									65
Repurchase and retirement of common stock	(447)			$ (1)	(53)	(393)
Repurchase and retirement of common stock, shares				(1.4)
Dividends and dividend equivalents	(281)					(281)
Issuance of common stock under employee stock plans, net of related tax benefits, Shares				0.9
Issuance of common stock under employee stock plans, net of related tax benefits	62				62
Net income	1,667
Other Comprehensive Income (Loss), Net of Tax	(347)
Balance (in shares), Ending at Mar. 31, 2021				244.9
Total shareholders' equity, Ending Balance at Mar. 31, 2021				$ 2	9,253	24,793			(195)
Noncontrolling interests, Ending Balance at Mar. 31, 2021										65
Total equity, Ending Balance at Mar. 31, 2021	33,918
Balance (in shares), Beginning at Dec. 31, 2020				245.4
Total shareholders' equity, Beginning Balance at Dec. 31, 2020	33,199			$ 3	9,244	23,802			150
Noncontrolling interests, Beginning Balance at Dec. 31, 2020	0									0
Total equity, Beginning Balance at Dec. 31, 2020	33,199
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shareholders' net income	3,458
Shareholders' other comprehensive income (loss)	(167)
Net income attributable to noncontrolling interests	10
Other comprehensive income attributable to noncontrolling interests	0
Repurchase and retirement of common stock	$ (927)
Repurchase and retirement of common stock, shares	(2.7)
Net income	$ 3,468
Other Comprehensive Income (Loss), Net of Tax	(167)
Balance (in shares), Ending at Jun. 30, 2021				243.9
Total shareholders' equity, Ending Balance at Jun. 30, 2021	34,968			$ 2	9,109	25,874			(17)
Noncontrolling interests, Ending Balance at Jun. 30, 2021	78									78
Total equity, Ending Balance at Jun. 30, 2021	35,046
Balance (in shares), Beginning at Mar. 31, 2021				244.9
Total shareholders' equity, Beginning Balance at Mar. 31, 2021				$ 2	9,253	24,793			(195)
Noncontrolling interests, Beginning Balance at Mar. 31, 2021										65
Total equity, Beginning Balance at Mar. 31, 2021	33,918
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shareholders' net income	1,793					1,793
Shareholders' other comprehensive income (loss)	178								178
Net income attributable to noncontrolling interests	8									8
Other comprehensive income attributable to noncontrolling interests	2									2
Noncontrolling interests adjustment	3									3
Repurchase and retirement of common stock	(480)				(47)	(433)
Repurchase and retirement of common stock, shares				(1.3)
Dividends and dividend equivalents	(279)					(279)
Issuance of common stock under employee stock plans, net of related tax benefits, Shares				0.3
Issuance of common stock under employee stock plans, net of related tax benefits	119				119
Convertible debenture repurchases and conversions	(216)				(216)
Net income	1,801
Other Comprehensive Income (Loss), Net of Tax	180
Balance (in shares), Ending at Jun. 30, 2021				243.9
Total shareholders' equity, Ending Balance at Jun. 30, 2021	34,968			$ 2	$ 9,109	$ 25,874			$ (17)
Noncontrolling interests, Ending Balance at Jun. 30, 2021	78									$ 78
Total equity, Ending Balance at Jun. 30, 2021	$ 35,046

Organization

Organization	6 Months Ended
	Jun. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization References to the terms “we,” “our,” “us” or “Anthem” used throughout these Notes to Consolidated Financial Statements refer to Anthem, Inc., an Indiana corporation, and unless the context otherwise requires, its direct and indirect subsidiaries. References to the “states” include the District of Columbia and Puerto Rico, unless the context otherwise requires. We are one of the largest health benefits companies in the United States in terms of medical membership, serving greater than 44 medical members through our affiliated health plans as of June 30, 2021. We offer a broad spectrum of network-based managed care plans to Individual, Group, Medicaid and Medicare markets. Our managed care plans include: Preferred Provider Organizations (“PPOs”); Health Maintenance Organizations (“HMOs”); Point-of-Service plans; traditional indemnity plans and other hybrid plans, including Consumer-Driven Health Plans; and hospital only and limited benefit products. In addition, we provide a broad array of managed care services to fee-based customers, including claims processing, stop loss insurance, actuarial services, provider network access, medical cost management, disease management, wellness programs and other administrative services. We provide an array of specialty and other insurance products and services such as pharmacy benefits management (“PBM”), dental, vision, life and disability insurance benefits, radiology benefit management and analytics-driven personal healthcare. We also provide services to the federal government in connection with our Federal Health Products & Services business, which administers the Federal Employees Health Benefits (“FEHB”) Program.

Basis Of Presentation and Signi

Basis Of Presentation and Significant Accounting Policies	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	Basis of Presentation and Significant Accounting Policies Basis of Presentation: The accompanying unaudited consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial reporting. Accordingly, they do not include all of the information and footnotes required by GAAP for annual financial statements. We have omitted certain footnote disclosures that would substantially duplicate the disclosures in our 2020 Annual Report on Form 10-K, unless the information contained in those disclosures materially changed or is required by GAAP. Certain prior year amounts have been reclassified to conform to the current year presentation. In the opinion of management, all adjustments, including normal recurring adjustments, necessary for a fair statement of the consolidated financial statements as of and for the three and six months ended June 30, 2021 and 2020 have been recorded. The results of operations for the three and six months ended June 30, 2021 are not necessarily indicative of the results that may be expected for the full year ending December 31, 2021, or any other period. These unaudited consolidated financial statements should be read in conjunction with our audited consolidated financial statements as of and for the year ended December 31, 2020 included in our 2020 Annual Report on Form 10-K. Certain of our subsidiaries operate outside of the United States and have functional currencies other than the U.S. dollar (“USD”). We translate the assets and liabilities of those subsidiaries to USD using the exchange rate in effect at the end of the period. We translate the revenues and expenses of those subsidiaries to USD using the average exchange rates in effect during the period. The net effect of these translation adjustments is included in “Foreign currency translation adjustments” in our consolidated statements of comprehensive income. Cash and Cash Equivalents: We control a number of bank accounts that are used exclusively to hold customer funds for the administration of customer benefits, and we have cash and cash equivalents on deposit to meet certain regulatory requirements. These amounts totaled $248 and $170 at June 30, 2021 and December 31, 2020, respectively, and are included in the cash and cash equivalents line on our consolidated balance sheets. Investments: We classify fixed maturity securities in our investment portfolio as “available-for-sale” and report those securities at fair value. Certain fixed maturity securities are available to support current operations and, accordingly, we classify such investments as current assets without regard to their contractual maturity. Investments used to satisfy contractual, regulatory or other requirements are classified as long-term, without regard to contractual maturity. If a fixed maturity security is in an unrealized loss position and we have the intent to sell the fixed maturity security, or it is more likely than not that we will have to sell the fixed maturity security before recovery of its amortized cost basis, we write down the fixed maturity security’s cost basis to fair value and record an impairment loss in our consolidated statements of income. For impaired fixed maturity securities that we do not intend to sell or if it is more likely than not that we will not have to sell such securities, but we expect that we will not fully recover the amortized cost basis, we recognize the credit component of the impairment as an allowance for credit loss in our consolidated balance sheets and record an impairment loss in our consolidated statements of income. The non-credit component of the impairment is recognized in accumulated other comprehensive (loss) income. Furthermore, unrealized losses entirely caused by non-credit-related factors related to fixed maturity securities for which we expect to fully recover the amortized cost basis continue to be recognized in accumulated other comprehensive (loss) income. The credit component of an impairment is determined primarily by comparing the net present value of projected future cash flows with the amortized cost basis of the fixed maturity security. The net present value is calculated by discounting our best estimate of projected future cash flows at the effective interest rate implicit in the fixed maturity security at the date of purchase. For mortgage-backed and asset-backed securities, cash flow estimates are based on assumptions regarding the underlying collateral, including prepayment speeds, vintage, type of underlying asset, geographic concentrations, default rates, recoveries and changes in value. For all other securities, cash flow estimates are driven by assumptions regarding probability of default, including changes in credit ratings and estimates regarding timing and amount of recoveries associated with a default. For asset-backed securities included in fixed maturity securities, we recognize income using an effective yield based on anticipated prepayments and the estimated economic life of the securities. When estimates of prepayments change, the effective yield is recalculated to reflect actual payments to date and anticipated future payments. The net investment in the securities is adjusted to the amount that would have existed had the new effective yield been applied since the purchase date of the securities. Such adjustments are reported within net investment income. The changes in fair value of our marketable equity securities are recognized in our results of operations within net realized gains and losses on financial instruments. Certain marketable equity securities are held to satisfy contractual obligations, and are reported under the caption “Other invested assets” in our consolidated balance sheets. We have corporate-owned life insurance policies on certain participants in our deferred compensation plans and other members of management. The cash surrender value of the corporate-owned life insurance policies is reported under the caption “Other invested assets” in our consolidated balance sheets. We use the equity method of accounting for investments in companies in which our ownership interest may enable us to influence the operating or financial decisions of the investee company. Our proportionate share of equity in net income of these unconsolidated affiliates is reported within net investment income. The equity method investments are reported under the caption “Other invested assets” in our consolidated balance sheets. Investment income is recorded when earned. All securities sold resulting in investment gains and losses are recorded on the trade date. Realized gains and losses are determined on the basis of the cost or amortized cost of the specific securities sold. We participate in securities lending programs whereby marketable securities in our investment portfolio are transferred to independent brokers or dealers in exchange for cash and securities collateral. We recognize the collateral as an asset, which is reported under the caption “Other current assets” in our consolidated balance sheets, and we record a corresponding liability for the obligation to return the collateral to the borrower, which is reported under the caption “Other current liabilities” in our consolidated balance sheets. The securities on loan are reported in the applicable investment category on our consolidated balance sheets. Unrealized gains or losses on securities lending collateral are included in accumulated other comprehensive (loss) income as a separate component of shareholders’ equity. The market value of loaned securities and that of the collateral pledged can fluctuate in non-synchronized fashions. To the extent the loaned securities’ value appreciates faster or depreciates slower than the value of the collateral pledged, we are exposed to the risk of the shortfall. As a primary mitigating mechanism, the loaned securities and collateral pledged are marked to market on a daily basis and the shortfall, if any, is collected accordingly. Secondarily, the collateral level is set at 102% of the value of the loaned securities, which provides a cushion before any shortfall arises. The investment of the cash collateral is subject to market risk, which is managed by limiting the investments to higher quality and shorter duration instruments. Receivables: Receivables are reported net of amounts for expected credit losses. The allowance for doubtful accounts is based on historical collection trends, future forecasts and our judgment regarding the ability to collect specific accounts. Premium receivables include the uncollected amounts from insured groups, individuals and government programs. Premium receivables are reported net of an allowance for doubtful accounts of $152 and $146 at June 30, 2021 and December 31, 2020, respectively. Self-funded receivables include administrative fees, claims and other amounts due from self-funded customers. Self-funded receivables are reported net of an allowance for doubtful accounts of $91 and $54 at June 30, 2021 and December 31, 2020, respectively. Other receivables include pharmacy rebates, provider advances, claims recoveries, reinsurance receivables, proceeds due from brokers on investment trades, accrued investment income, and other miscellaneous amounts due to us. These receivables are reported net of an allowance for doubtful accounts of $479 and $374 at June 30, 2021 and December 31, 2020, respectively. Revenue Recognition: For our fee-based contracts, we had no material contract assets, contract liabilities or deferred contract costs recorded on our consolidated balance sheet at June 30, 2021. For the three and six months ended June 30, 2021, revenue recognized from performance obligations related to prior periods, such as due to changes in transaction price, was not material. For contracts that have an original expected duration of greater than one year, revenue expected to be recognized in future periods related to unfulfilled contractual performance obligations and contracts with variable consideration related to undelivered performance obligations is not material. Recently Adopted Accounting Guidance: In January 2021, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2021-01, Reference Rate Reform (Topic 848) (“ASU 2021-01”). The amendments in ASU 2021-01 provide optional expedients and exceptions for applying GAAP to contract modifications and hedging relationships, subject to meeting certain criteria, that reference the London Interbank Offered Rate (“LIBOR”) or another reference rate expected to be discontinued because of the reference rate reform. The provisions must be applied at a Topic, Subtopic, or Industry Subtopic level for all transactions other than derivatives, which may be applied at a hedging relationship level. We adopted ASU 2021-01 on January 7, 2021 and the adoption did not have an impact on our consolidated financial position, results of operations or cash flows. In October 2020, the FASB issued Accounting Standards Update No. 2020-08, Codification Improvements to Subtopic 310-20, Receivables—Nonrefundable Fees and Other Costs (“ASU 2020-08”). The amendments in ASU 2020-08 clarify when an entity should assess whether a callable debt security is within the scope of accounting guidance, which impacts the amortization period for nonrefundable fees and other costs. ASU 2020-08 became effective for interim and annual reporting periods beginning after December 15, 2020. The amendments are to be applied on a prospective basis as of the beginning of the period of adoption for existing or newly purchased callable debt securities. We adopted ASU 2020-08 on January 1, 2021, and the adoption did not have an impact on our consolidated financial position, results of operations or cash flows. In December 2019, the FASB issued Accounting Standards Update No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (“ASU 2019-12”). The amendments in ASU 2019-12 remove certain exceptions to the general principles in Accounting Standards Codification Topic 740. The amendments also clarify and amend existing guidance to improve consistent application. The amendments became effective for our annual reporting periods beginning after December 15, 2020. The transition method (retrospective, modified retrospective, or prospective basis) related to the amendments depends on the applicable guidance, and all amendments for which there is no transition guidance specified are to be applied on a prospective basis. We adopted ASU 2019-12 on January 1, 2021, and the adoption did not have an impact on our consolidated financial position, results of operations or cash flows. Recent Accounting Guidance Not Yet Adopted: In November 2020, the FASB issued Accounting Standards Update No. 2020-11, Financial Services—Insurance (Topic 944): Effective Date and Early Application (“ASU 2020-11”). The amendments in ASU 2020-11 make changes to the effective date and early application of Accounting Standards Update No. 2018-12, Financial Services—Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (“ASU 2018-12”), which was issued in November 2018. The amendments in ASU 2020-11 have extended the original effective date by one year, and now the amendments are required for our interim and annual reporting periods beginning after December 15, 2022. The amendments in ASU 2018-12 make changes to a variety of areas to simplify or improve the existing recognition, measurement, presentation and disclosure requirements for long-duration contracts issued by an insurance entity. The amendments require insurers to annually review the assumptions they make about their policyholders and update the liabilities for future policy benefits if the assumptions change. The amendments also simplify the amortization of deferred contract acquisition costs and add new disclosure requirements about the assumptions insurers use to measure their liabilities and how they may affect future cash flows. The amendments related to the liability for future policy benefits for traditional and limited-payment contracts and deferred acquisition costs are to be applied to contracts in force as of the beginning of the earliest period presented, with an option to apply such amendments retrospectively with a cumulative-effect adjustment to the opening balance of retained earnings as of the earliest period presented. The amendments for market risk benefits are to be applied retrospectively. We are currently evaluating the effects the adoption of ASU 2020-11 and ASU 2018-12 will have on our consolidated financial position, results of operations, cash flows, and related disclosures. In August 2020, the FASB issued Accounting Standards Update No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity (“ASU 2020-06”) . The amendments eliminate two of the three accounting models that require separate accounting for convertible features of debt securities, simplify the contract settlement assessment for equity classification, require the use of the if-converted method for all convertible instruments in the diluted earnings per share calculation and expand disclosure requirements. The amendments are effective for our annual and interim reporting periods beginning after December 15, 2021, with early adoption permitted for reporting periods beginning after December 15, 2020. The guidance can be applied on a full retrospective basis to all periods presented or a modified retrospective basis with a cumulative effect adjustment to the opening balance of retained earnings during the period of adoption. We are currently evaluating the effects the adoption of ASU 2020-06 will have on our consolidated financial statements and disclosures. There were no other new accounting pronouncements that were issued or became effective since the issuance of our 2020 Annual Report on Form 10-K that had, or are expected to have, a material impact on our consolidated financial position, results of operations or cash flows.

Business Acquisitions

Business Acquisitions	6 Months Ended
	Jun. 30, 2021
Business Combinations [Abstract]
Business Acquisitions	Business Acquisitions MMM Holdings, LLC and Affiliates On June 29, 2021, we completed our acquisition of MMM Holdings, LLC (“MMM”), and its Medicare Advantage plan, Medicaid plan and other affiliated companies from InnovaCare Health, L.P. MMM is a Puerto Rico based integrated healthcare organization and seeks to provide its Medicare Advantage and Medicaid members with a whole health experience through its network of specialized clinics and wholly owned independent physician associations. This acquisition aligns with our vision to be an innovative, valuable and inclusive healthcare partner by providing care management programs that improve the lives of the people we serve. In accordance with FASB accounting guidance for business combinations, the consideration transferred was allocated to the fair value of MMM’s assets acquired and liabilities assumed, including identifiable intangible assets. The excess of consideration transferred over the fair value of net assets acquired resulted in preliminary goodwill of $2,171 at June 30, 2021, all of which was allocated to our Government Business segment. Preliminary goodwill recognized from the acquisition of MMM primarily relates to the future economic benefits arising from the assets acquired and is consistent with our stated intentions and strategy. The preliminary fair value of MMM’s identifiable intangible assets was $968 at June 30, 2021. The results of operations of MMM for the period from June 29, 2021 through June 30, 2021 were not material and are not included in our consolidated financial statements as of June 30, 2021. The proforma effects of this acquisition for prior periods were not material to our consolidated results of operations. myNEXUS, Inc. On April 28, 2021, we completed our acquisition of myNEXUS, Inc. (“myNEXUS”) from WindRose Health Investors, a comprehensive home-based nursing management company for payors. At the time of acquisition, myNEXUS delivered integrated clinical support services for Medicare Advantage members across twenty states. This acquisition aligns with our strategy to manage integrated, whole person multi-site care and support, by providing national, large-scale expertise to manage nursing services in the home and facilitate transitions of care. In accordance with FASB accounting guidance for business combinations, the consideration transferred was allocated to the fair value of myNEXUS’ assets acquired and liabilities assumed, including identifiable intangible assets. The excess of consideration transferred over the fair value of net assets acquired resulted in preliminary goodwill of $520 at June 30, 2021, all of which was allocated to our Other segment. Preliminary goodwill recognized from the acquisition of myNEXUS primarily relates to the future economic benefits arising from the assets acquired and is consistent with our stated intentions and strategy. The fair value of the net assets acquired from myNEXUS includes $284 of other intangible assets at June 30, 2021, which primarily consist of finite-lived customer relationships with amortization periods ranging from 2 to 17 years. The results of operations of myNEXUS are included in our consolidated financial statements within our Other segment for the period following April 28, 2021. The proforma effects of this acquisition for prior periods were not material to our consolidated results of operations. Beacon Health Options, Inc. On February 28, 2020, we completed our acquisition of Beacon Health Options, Inc. (“Beacon”), which was the largest independently held behavioral health organization in the country. At the time of acquisition, Beacon served more than thirty-four million individuals across all fifty states. This acquisition aligned with our strategy to diversify into health services and deliver both integrated solutions and care delivery models that personalize care for people with complex and chronic conditions. In accordance with FASB accounting guidance for business combinations, the consideration transferred was allocated to the fair value of Beacon’s assets acquired and liabilities assumed, including identifiable intangible assets. The excess of the consideration transferred over the fair value of net assets acquired resulted in preliminary goodwill of $1,072 at December 31, 2020, all of which was allocated to our Other segment. Preliminary goodwill recognized from the acquisition of Beacon primarily relates to the future economic benefits arising from the assets acquired and is consistent with our stated intentions and strategy. Goodwill was adjusted by $9 through the end of the measurement period in February 2021 related to finalization of income tax considerations, resulting in final goodwill of $1,081 as of June 30, 2021. The fair value of the net assets acquired from Beacon includes $752 of other intangible assets at June 30, 2021, which primarily consist of finite-lived customer relationships with amortization periods ranging from 8 to 25 years. The results of operations of Beacon are included in our consolidated financial statements within our Other segment for the period following

Business Optimization Initiativ

Business Optimization Initiatives	6 Months Ended
	Jun. 30, 2021
Business Optimization Initiatives [Abstract]
Business Optimization Initiatives	Business Optimization Initiatives During 2020, management introduced enterprise-wide initiatives to optimize our business, including process automation and a reduction in our office space footprint and, as a result, we recognized a liability in 2020 for future payments for employee termination costs in connection with the repositioning and reskilling of our workforce. We believe these initiatives largely represent the next step forward in our progression towards becoming a more agile organization. A summary of the activity related to the liability for the employee termination costs during the six months ended June 30, 2021, by reportable segment, is as follows: Commercial & Specialty Business Government Business IngenioRx Other Total 2020 Business Optimization Initiatives Employee termination costs: Liability for employee termination costs at January 1, 2021 $ 92 $ 88 $ 1 $ 6 $ 187 Payments (12) (13) — (1) (26) Liability for employee termination costs at June 30, 2021 $ 80 $ 75 $ 1 $ 5 $ 161

Investments

Investments	6 Months Ended
	Jun. 30, 2021
Investments [Abstract]
Investments	Investments Fixed Maturity Securities We evaluate our available-for-sale fixed maturity securities for declines based on qualitative and quantitative factors. We have established an allowance for credit loss and recorded credit loss expense as a reflection of our expected impairment losses. We continue to review our investment portfolios under our impairment review policy. Given the inherent uncertainty of changes in market conditions and the significant judgments involved, there is a continuing risk that declines in fair value may occur and additional material impairment losses on investments may be recorded in future periods. A summary of current and long-term fixed maturity securities, available-for-sale, at June 30, 2021 and December 31, 2020 is as follows: Cost or Non-Credit Gross Gross Unrealized Losses Allowance Estimated Less than 12 Months June 30, 2021 Fixed maturity securities: United States Government securities $ 1,322 $ 10 $ (12) $ — $ — $ 1,320 $ — Government sponsored securities 60 5 — — — 65 — Foreign government securities 344 10 (3) (1) — 350 — States, municipalities and political subdivisions 5,126 360 (2) (1) — 5,483 — Corporate securities 11,661 558 (31) (8) (4) 12,176 — Residential mortgage-backed securities 4,337 117 (12) (8) (2) 4,432 — Commercial mortgage-backed securities 73 3 — (3) — 73 — Other securities 2,506 32 (2) (6) — 2,530 — Total fixed maturity securities $ 25,429 $ 1,095 $ (62) $ (27) $ (6) $ 26,429 $ — December 31, 2020 Fixed maturity securities: United States Government securities $ 765 $ 11 $ (2) $ — $ — $ 774 $ — Government sponsored securities 63 6 — — — 69 — Foreign government securities 290 17 (2) — — 305 — States, municipalities and political subdivisions 5,185 395 (1) — — 5,579 — Corporate securities 10,233 697 (20) (11) (7) 10,892 (1) Residential mortgage-backed securities 4,208 154 (8) (9) — 4,345 (2) Commercial mortgage-backed securities 73 3 (1) (3) — 72 — Other securities 1,937 33 (5) (6) — 1,959 — Total fixed maturity securities $ 22,754 $ 1,316 $ (39) $ (29) $ (7) $ 23,995 $ (3) For fixed maturity securities in an unrealized loss position at June 30, 2021 and December 31, 2020, the following table summarizes the aggregate fair values and gross unrealized losses by length of time those securities have continuously been in an unrealized loss position: Less than 12 Months 12 Months or Greater (Securities are whole amounts) Number of Estimated Gross Number of Estimated Gross June 30, 2021 Fixed maturity securities: United States Government securities 62 $ 766 $ (12) 1 $ 8 $ — Government sponsored securities 1 1 — — — — Foreign government securities 153 114 (3) 22 11 (1) States, municipalities and political subdivisions 132 231 (2) 4 11 (1) Corporate securities 1,158 1,718 (31) 179 204 (8) Residential mortgage-backed securities 385 1,372 (12) 108 147 (8) Commercial mortgage-backed securities — — — 4 8 (3) Other securities 228 665 (2) 58 112 (6) Total fixed maturity securities 2,119 $ 4,867 $ (62) 376 $ 501 $ (27) December 31, 2020 Fixed maturity securities: United States Government securities 27 $ 301 $ (2) — $ — $ — Government sponsored securities — — — 1 — — Foreign government securities 55 35 (2) 9 4 — States, municipalities and political subdivisions 36 57 (1) 1 3 — Corporate securities 646 765 (20) 150 169 (11) Residential mortgage-backed securities 224 442 (8) 90 110 (9) Commercial mortgage-backed securities 6 16 (1) 3 4 (3) Other securities 207 509 (5) 79 179 (6) Total fixed maturity securities 1,201 $ 2,125 $ (39) 333 $ 469 $ (29) Below are discussions by security type for unrealized losses and credit losses as of June 30, 2021: Corporate securities: An allowance for credit losses on certain retail, travel and entertainment and energy sector fixed maturity corporate securities has been determined based on qualitative and quantitative factors including credit rating, decline in fair value and industry condition along with other available market data. With multiple risk factors present, these securities were reviewed for expected future cash flow to determine the portion of unrealized losses that were credit related and to record an allowance for credit losses. Unrealized losses on our other corporate securities were largely due to market conditions relating to the COVID-19 pandemic; however, qualitative factors did not indicate a credit loss as of June 30, 2021. We do not intend to sell these investments and it is likely we will not have to sell these investments prior to maturity or recovery of amortized cost. Residential mortgage-backed securities: An allowance for credit loss was established on certain residential mortgage-backed securities. Notification of maturity and coupon default, as well as a significant and sustained decline in fair value, were factors to indicate a credit loss. No other mortgage securities had material unrealized losses or qualitative factors to indicate a credit loss. We do not intend to sell these investments and it is likely we will not be required to sell these investments prior to maturity or recovery of amortized cost. As for the remaining securities shown in the table above, unrealized losses on these securities have not been recognized into income because we do not intend to sell these investments and it is likely that we will not be required to sell these investments prior to their anticipated recovery. The decline in fair value is largely due to changes in interest rates and other market conditions. We have evaluated these securities for any change in credit rating and have determined that no allowance is necessary. The fair value is expected to recover as the securities approach maturity. The table below presents a roll-forward by major security type of the allowance for credit losses on fixed maturity securities available-for-sale held at period end for the three and six months ended June 30, 2021 and 2020: Three Months Ended June 30, 2021 Six Months Ended June 30, 2021 Corporate Securities Residential mortgage-backed securities Total Corporate Securities Residential mortgage-backed securities Total Allowance for credit losses: Beginning balance $ 6 $ 2 $ 8 $ 7 $ — $ 7 Additions for securities for which no previous expected credit losses were recognized — — — 1 — 1 Securities sold during the period (2) — (2) (2) — (2) (Decreases) increases to the allowance for credit losses on securities — — — (2) 2 — Total allowance for credit losses, ending balance $ 4 $ 2 $ 6 $ 4 $ 2 $ 6 Three Months Ended June 30, 2020 Six Months Ended June 30, 2020 Corporate Securities Foreign Government Securities Total Corporate Securities Foreign Government Securities Total Allowance for credit losses: Beginning balance $ 51 $ — $ 51 $ — $ — $ — Additions for securities for which no previous expected credit losses were recognized 9 1 10 60 1 61 Securities sold during the period (8) — (8) (8) — (8) Decreases to the allowance for credit losses on securities (29) — (29) (29) — (29) Total allowance for credit losses, ending balance $ 23 $ 1 $ 24 $ 23 $ 1 $ 24 The amortized cost and fair value of fixed maturity securities at June 30, 2021, by contractual maturity, are shown below. Expected maturities may differ from contractual maturities because the issuers of the securities may have the right to prepay obligations. Amortized Estimated Due in one year or less $ 745 $ 749 Due after one year through five years 6,392 6,644 Due after five years through ten years 8,370 8,673 Due after ten years 5,512 5,858 Mortgage-backed securities 4,410 4,505 Total fixed maturity securities $ 25,429 $ 26,429 Proceeds from sales, maturities, calls or redemptions of fixed maturity securities during the three and six months ended June 30, 2021 and 2020 are as follows: Three Months Ended June 30 Six Months Ended June 30 2021 2020 2021 2020 Proceeds $ 627 $ 2,618 $ 5,950 $ 4,549 In the ordinary course of business, we may sell securities at a loss for a number of reasons, including, but not limited to: (i) changes in the investment environment; (ii) expectation that the fair value could deteriorate further; (iii) desire to reduce exposure to an issuer or an industry; (iv) changes in credit quality; or (v) changes in expected cash flow. All securities sold resulting in investment gains and losses are recorded on the trade date. Realized gains and losses are determined on the basis of the cost or amortized cost of the specific securities sold. Equity Securities A summary of marketable equity securities at June 30, 2021 and December 31, 2020 is as follows: June 30, 2021 December 31, 2020 Equity securities: Exchange traded funds $ 1,596 $ 1,154 Fixed maturity mutual funds — 144 Common equity securities 73 201 Private equity securities 77 60 Total $ 1,746 $ 1,559 Other Invested Assets Other invested assets include primarily our investments in limited partnerships, joint ventures and other non-controlled corporations, as well as the cash surrender value of corporate-owned life insurance policies. Investments in limited partnerships, joint ventures and other non-controlled corporations are carried at our share in the entities’ undistributed earnings, which approximates fair value. Financial information for certain of these investments are reported on a one or three month lag due to the timing of when we receive financial information from the companies. Investment Gains and Losses Net realized investment gains (losses) on investments for the three and six months ended June 30, 2021 and 2020 are as follows: Three Months Ended June 30 Six Months Ended June 30 2021 2020 2021 2020 Net realized gains (losses): Fixed maturity securities: Gross realized gains from sales $ 47 $ 37 $ 103 $ 80 Gross realized losses from sales (12) (50) (24) (70) Impairment recoveries (losses) recognized in income 2 27 1 (24) Net realized gains (losses) from sales of fixed maturity securities 37 14 80 (14) Equity securities: Gross realized gains 23 64 28 65 Gross realized losses (5) (19) (76) (70) Net realized gains (losses) on equity securities 18 45 (48) (5) Other invested assets: Gross realized gains 90 — 95 6 Impairment recoveries (losses) recognized in income 2 (29) (6) (35) Net realized gains (losses) from sales of other investments 92 (29) 89 (29) Net realized gains (losses) on investments $ 147 $ 30 $ 121 $ (48) The gains and losses related to equity securities for the three and six months ended June 30, 2021 and 2020 are as follows: Three Months Ended June 30 Six Months Ended June 30 2021 2020 2021 2020 Net realized gains (losses) recognized on equity securities $ 18 $ 45 $ (48) $ (5) Less: Net realized gains (losses) recognized on equity securities sold during the period 1 20 (56) 5 Unrealized gains (losses) recognized on equity securities still held at the end of the period $ 17 $ 25 $ 8 $ (10) Accrued Investment Income At June 30, 2021 and December 31, 2020, accrued investment income totaled $195 and $188, respectively. We recognize accrued investment income under the caption “Other receivables” on our consolidated balance sheets. Securities Lending Programs We participate in securities lending programs whereby marketable securities in our investment portfolio are transferred to independent brokers or dealers in exchange for cash and securities collateral. The fair value of the collateral received at the time of the transactions amounted to $1,841 and $1,199 at June 30, 2021 and December 31, 2020, respectively. The value of the collateral represented 102% of the market value of the securities on loan at each of June 30, 2021 and December 31, 2020. We recognize the collateral as an asset under the caption “Other current assets” in our consolidated balance sheets, and we recognize a corresponding liability for the obligation to return the collateral to the borrower under the caption “Other current liabilities.” The securities on loan are reported in the applicable investment category on our consolidated balance sheets. The remaining contractual maturity of our securities lending agreements at June 30, 2021 is as follows: Overnight and Continuous Securities lending collateral Cash $ 1,739 United States Government securities 102 Total $ 1,841

Derivative Financial Instrument

Derivative Financial Instruments	6 Months Ended
	Jun. 30, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments We primarily invest in the following types of derivative financial instruments: interest rate swaps, futures, forward contracts, put and call options, swaptions, embedded derivatives and warrants. We also enter into master netting agreements, which reduce credit risk by permitting net settlement of transactions. We have entered into various interest rate swap contracts to convert a portion of our interest rate exposure on our long-term debt from fixed rates to floating rates. The floating rates payable on all of our fair value hedges are benchmarked to LIBOR. Any amounts recognized for changes in fair value of these derivatives are included in the captions “Other current assets” or “Other noncurrent assets” or “Other current liabilities” or “Other noncurrent liabilities” in our consolidated balance sheets. We have previously entered into a series of forward starting pay fixed interest rate swaps with the objective of reducing the variability of cash flows in the interest payments on future financings that were anticipated at the time of entering into the swaps. All swaps were expired or terminated as of June 30, 2021. The unrecognized loss for all expired and terminated cash flow hedges included in accumulated other comprehensive (loss) income, net of tax, was $244 and $250 at June 30, 2021 and December 31, 2020, respectively. During the three and six months ended June 30, 2021 , we recognized net realized gains on non-hedging derivatives of $25 and $47, respectively. During the three and six months ended June 30, 2020, we recognized net realized losses on non-hedging derivatives of $1 and $4, respectively. For additional information relating to the fair value of our derivative assets and liabilities, see Note 7, “Fair Value,” of this Form 10-Q.

Fair Value

Fair Value	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value	Fair Value Assets and liabilities recorded at fair value in our consolidated balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair value. Level inputs, as defined by FASB guidance for fair value measurements and disclosures, are as follows: Level Input Input Definition Level I Inputs are unadjusted, quoted prices for identical assets or liabilities in active markets at the measurement date. Level II Inputs other than quoted prices included in Level I that are observable for the asset or liability through corroboration with market data at the measurement date. Level III Unobservable inputs that reflect management’s best estimate of what market participants would use in pricing the asset or liability at the measurement date. The following methods, assumptions and inputs were used to determine the fair value of each class of the following assets and liabilities recorded at fair value in our consolidated balance sheets: Cash equivalents: Cash equivalents primarily consist of highly rated money market funds with maturities of three months or less and are purchased daily at par value with specified yield rates. Due to the high ratings and short-term nature of the funds, we designate all cash equivalents as Level I. Fixed maturity securities, available-for-sale: Fair values of available-for-sale fixed maturity securities are based on quoted market prices, where available. These fair values are obtained primarily from third-party pricing services, which generally use Level I or Level II inputs for the determination of fair value to facilitate fair value measurements and disclosures. Level II securities primarily include corporate securities, securities from states, municipalities and political subdivisions, mortgage-backed securities, United States Government securities, foreign government securities, and certain other asset-backed securities. For securities not actively traded, the pricing services 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. We have controls in place to review the pricing services’ qualifications and procedures used to determine fair values. In addition, we periodically review the pricing services’ pricing methodologies, data sources and pricing inputs to ensure the fair values obtained are reasonable. Inputs that are often used in the valuation methodologies include, but are not limited to, broker quotes, benchmark yields, credit spreads, default rates and prepayment speeds. We also have certain fixed maturity securities, primarily corporate debt securities, which are designated Level III securities. For these securities, the valuation methodologies may incorporate broker quotes or discounted cash flow analyses using assumptions for inputs such as expected cash flows, benchmark yields, credit spreads, default rates and prepayment speeds that are not observable in the markets. Equity securities: Fair values of equity securities are generally designated as Level I and are based on quoted market prices. For certain equity securities, quoted market prices for the identical security are not always available, and the fair value is estimated by reference to similar securities for which quoted prices are available. These securities are designated Level II. We also have certain equity securities, including private equity securities, for which the fair value is estimated based on each security’s current condition and future cash flow projections. Such securities are designated Level III. The fair values of these private equity securities are generally based on either broker quotes or discounted cash flow projections using assumptions for inputs such as the weighted-average cost of capital, long-term revenue growth rates and earnings before interest, taxes, depreciation and amortization, and/or revenue multiples that are not observable in the markets. Securities lending collateral: Fair values of securities lending collateral are based on quoted market prices, where available. These fair values are obtained primarily from third-party pricing services, which generally use Level I or Level II inputs for the determination of fair value, to facilitate fair value measurements and disclosures. Derivatives: Fair values are based on the quoted market prices by the financial institution that is the counterparty to the derivative transaction. We independently verify prices provided by the counterparties using valuation models that incorporate observable market inputs for similar derivative transactions. Derivatives are designated as Level II securities. Derivatives presented within the fair value hierarchy table below are presented on a gross basis and not on a master netting basis by counterparty. A summary of fair value measurements by level for assets and liabilities measured at fair value on a recurring basis at June 30, 2021 and December 31, 2020 is as follows: Level I Level II Level III Total June 30, 2021 Assets: Cash equivalents $ 2,044 $ — $ — $ 2,044 Fixed maturity securities, available-for-sale: United States Government securities — 1,320 — 1,320 Government sponsored securities — 65 — 65 Foreign government securities — 350 — 350 States, municipalities and political subdivisions, tax-exempt — 5,483 — 5,483 Corporate securities — 11,825 351 12,176 Residential mortgage-backed securities — 4,430 2 4,432 Commercial mortgage-backed securities — 73 — 73 Other securities — 2,523 7 2,530 Total fixed maturity securities, available-for-sale — 26,069 360 26,429 Equity securities: Exchange traded funds 1,596 — — 1,596 Common equity securities 6 67 — 73 Private equity securities — — 77 77 Total equity securities 1,602 67 77 1,746 Other invested assets - common equity securities 184 — — 184 Securities lending collateral — 1,841 — 1,841 Derivatives — 91 — 91 Total assets $ 3,830 $ 28,068 $ 437 $ 32,335 Liabilities: Derivatives $ — $ (31) $ — $ (31) Total liabilities $ — $ (31) $ — $ (31) December 31, 2020 Assets: Cash equivalents $ 3,163 $ — $ — $ 3,163 Fixed maturity securities, available-for-sale: United States Government securities — 774 — 774 Government sponsored securities — 69 — 69 Foreign government securities — 305 — 305 States, municipalities and political subdivisions, tax-exempt — 5,579 — 5,579 Corporate securities — 10,567 325 10,892 Residential mortgage-backed securities — 4,343 2 4,345 Commercial mortgage-backed securities — 72 — 72 Other securities — 1,954 5 1,959 Total fixed maturity securities, available-for-sale — 23,663 332 23,995 Equity securities: Exchange traded funds 1,154 — — 1,154 Fixed maturity mutual funds — 144 — 144 Common equity securities 171 30 — 201 Private equity securities — — 60 60 Total equity securities 1,325 174 60 1,559 Securities lending collateral — 1,199 — 1,199 Derivatives — 43 — 43 Total assets $ 4,488 $ 25,079 $ 392 $ 29,959 Liabilities: Derivatives $ — $ (5) $ — $ (5) Total liabilities $ — $ (5) $ — $ (5) A reconciliation of the beginning and ending balances of assets measured at fair value on a recurring basis using Level III inputs for the three months ended June 30, 2021 and 2020 is as follows: Corporate Residential Other Equity Total Three Months Ended June 30, 2021 Beginning balance at April 1, 2021 $ 324 $ 2 $ 5 $ 65 $ 396 Total gains: Recognized in net income — — — 5 5 Recognized in accumulated other comprehensive (loss) income 3 — — — 3 Purchases 65 — 2 8 75 Sales (9) — — (1) (10) Settlements (32) — — — (32) Ending balance at June 30, 2021 $ 351 $ 2 $ 7 $ 77 $ 437 Change in unrealized losses included in net income related to assets still held at June 30, 2021 $ — $ — $ — $ 5 $ 5 Three Months Ended June 30, 2020 Beginning balance at April 1, 2020 $ 316 $ 2 $ 5 $ 82 $ 405 Total gains (losses): Recognized in net income 1 — — (10) (9) Recognized in accumulated other comprehensive (loss) income (7) — — — (7) Purchases 14 — — 3 17 Sales (1) — — (13) (14) Settlements (9) — — — (9) Ending balance at June 30, 2020 $ 314 $ 2 $ 5 $ 62 $ 383 Change in unrealized losses included in net income related to assets still held at June 30, 2020 $ — $ — $ — $ (10) $ (10) A reconciliation of the beginning and ending balances of assets measured at fair value on a recurring basis using Level III inputs for the six months ended June 30, 2021 and 2020 is as follows: Corporate Residential Other Equity Total Six Months Ended June 30, 2021 Beginning balance at January 1, 2021 $ 325 $ 2 $ 5 $ 60 $ 392 Total gains: Recognized in net income — — — 13 13 Recognized in accumulated other comprehensive (loss) income 6 — — — 6 Purchases 104 — 2 8 114 Sales (11) — — (4) (15) Settlements (73) — — — (73) Ending balance at June 30, 2021 $ 351 $ 2 $ 7 $ 77 $ 437 Change in unrealized losses included in net income related to assets still held at June 30, 2021 $ — $ — $ — $ 13 $ 13 Six Months Ended June 30, 2020 Beginning balance at January 1, 2020 $ 303 $ 2 $ 7 $ 85 $ 397 Total losses: Recognized in net income (1) — — (16) (17) Recognized in accumulated other comprehensive (loss) income (17) — — — (17) Purchases 39 — — 15 54 Sales (4) — — (22) (26) Settlements (19) — (2) — (21) Transfers into Level III 13 — — — 13 Ending balance at June 30, 2020 $ 314 $ 2 $ 5 $ 62 $ 383 Change in unrealized losses included in net income related to assets still held at June 30, 2020 $ — $ — $ — $ (17) $ (17) There were no individually material transfers into or out of Level III during the three and six months ended June 30, 2021 or 2020. Certain assets and liabilities are measured at fair value on a nonrecurring basis; that is, the instruments are not measured at fair value on an ongoing basis but are subject to fair value adjustments only in certain circumstances. As disclosed in Note 3, “Business Acquisitions,” we completed our acquisitions of myNEXUS and MMM during the second quarter of 2021, as well as our acquisition of Beacon during the first quarter of 2020. The net assets acquired in our acquisitions of Beacon, myNEXUS and MMM and resulting goodwill and other intangible assets were recorded at fair value primarily using Level III inputs. The majority of assets acquired and liabilities assumed were recorded at their carrying values as of the respective date of acquisition, as their carrying values approximated their fair values due to their short-term nature. The fair values of goodwill and other intangible assets acquired in our acquisitions of Beacon, myNEXUS and MMM were internally estimated based on the income approach. The income approach estimates fair value based on the present value of the cash flows that the assets could be expected to generate in the future. We developed internal estimates for the expected cash flows and discount rate in the present value calculation. Other than the assets acquired and liabilities assumed in our acquisitions of Beacon, myNEXUS and MMM described above, there were no material assets or liabilities measured at fair value on a nonrecurring basis during the three and six months ended June 30, 2021 or 2020. Our valuation policy is determined by members of our treasury and accounting departments. Whenever possible, our policy is to obtain quoted market prices in active markets to estimate fair values for recognition and disclosure purposes. Where quoted market prices in active markets are not available, fair values are estimated using discounted cash flow analyses, broker quotes, unobservable inputs or other valuation techniques. These techniques are significantly affected by our assumptions, including discount rates and estimates of future cash flows. The use of assumptions for unobservable inputs for the determination of fair value involves a level of judgment and uncertainty. Changes in assumptions that reasonably could have been different at the reporting date may result in a higher or lower determination of fair value. Changes in fair value measurements, if significant, may affect performance of cash flows. Potential taxes and other transaction costs are not considered in estimating fair values. Our valuation policy is generally to obtain quoted prices for each security from third-party pricing services, which are derived through recently reported trades for identical or similar securities making adjustments through the reporting date based upon available market observable information. As we are responsible for the determination of fair value, we perform analysis on the prices received from the pricing services to determine whether the prices are reasonable estimates of fair value. This analysis is performed by our internal treasury personnel who are familiar with our investment portfolios, the pricing services engaged and the valuation techniques and inputs used. Our analysis includes procedures such as a review of month-to-month price fluctuations and price comparisons to secondary pricing services. There were no adjustments to quoted market prices obtained from the pricing services during the three and six months ended June 30, 2021 or 2020. In addition to the preceding disclosures on assets recorded at fair value in the consolidated balance sheets, FASB guidance also requires the disclosure of fair values for certain other financial instruments for which it is practicable to estimate fair value, whether or not such values are recognized in our consolidated balance sheets. Non-financial instruments such as real estate, property and equipment, other current or noncurrent assets, deferred income taxes, intangible assets and certain financial instruments, such as policy liabilities, are excluded from the fair value disclosures. Therefore, the fair value amounts cannot be aggregated to determine our underlying economic value. The carrying amounts for cash, premium receivables, self-funded receivables, other receivables, unearned income, accounts payable and accrued expenses, and certain other current liabilities approximate fair value because of the short-term nature of these items. These assets and liabilities are not listed in the table below. The following methods and assumptions were used to estimate the fair value of each class of financial instrument that is recorded at its carrying value in our consolidated balance sheets: Other invested assets: Other invested assets include primarily our investments in limited partnerships, joint ventures and other non-controlled corporations, as well as the cash surrender value of corporate-owned life insurance policies. Investments in limited partnerships, joint ventures and other non-controlled corporations are carried at our share in the entities’ undistributed earnings, which approximates fair value. The carrying value of corporate-owned life insurance policies represents the cash surrender value as reported by the respective insurer, which approximates fair value. Short-term borrowings: The fair value of our short-term borrowings is based on quoted market prices for the same or similar debt, or, if no quoted market prices were available, on the current market interest rates estimated to be available to us for debt of similar terms and remaining maturities. Long-term debt – commercial paper: The carrying amount for commercial paper approximates fair value, as the underlying instruments have variable interest rates at market value. Long-term debt – senior unsecured notes and surplus notes: The fair values of our notes are based on quoted market prices in active markets for the same or similar debt, or, if no quoted market prices are available, on the current market observable rates estimated to be available to us for debt of similar terms and remaining maturities. Long-term debt – convertible debentures: The fair value of our convertible debentures is based on the quoted market price in the active private market in which the convertible debentures trade. A summary of the estimated fair values by level of each class of financial instrument that is recorded at its carrying value on our consolidated balance sheets at June 30, 2021 and December 31, 2020 is as follows: Carrying Estimated Fair Value Level I Level II Level III Total June 30, 2021 Assets: Other invested assets $ 4,733 $ — $ — $ 4,733 $ 4,733 Liabilities: Debt: Short-term borrowings 175 — 175 — 175 Commercial paper 550 — 550 — 550 Notes 22,439 — 25,425 — 25,425 Convertible debentures 77 — 610 — 610 December 31, 2020 Assets: Other invested assets $ 4,285 $ — $ — $ 4,285 $ 4,285 Liabilities: Debt: Commercial paper 250 — 250 — 250 Notes 19,677 — 23,307 — 23,307 Convertible debentures 108 — 712 — 712

Medical Claims Payable

Medical Claims Payable	6 Months Ended
	Jun. 30, 2021
Liability for Claims and Claims Adjustment Expense [Abstract]
Medical Claims payable	Medical Claims Payable A reconciliation of the beginning and ending balances for medical claims payable, by segment (see Note 15, “Segment Information”), for the six months ended June 30, 2021 is as follows: Commercial Government Other Total Gross medical claims payable, beginning of period $ 3,294 $ 7,646 $ 195 $ 11,135 Ceded medical claims payable, beginning of period (13) (33) — (46) Net medical claims payable, beginning of period 3,281 7,613 195 11,089 Business combinations and purchase adjustments — 375 45 420 Net incurred medical claims: Current period 13,360 34,232 751 48,343 Prior periods redundancies (570) (1,190) (12) (1,772) Total net incurred medical claims 12,790 33,042 739 46,571 Net payments attributable to: Current period medical claims 10,295 26,647 591 37,533 Prior periods medical claims 2,154 5,455 158 7,767 Total net payments 12,449 32,102 749 45,300 Net medical claims payable, end of period 3,622 8,928 230 12,780 Ceded medical claims payable, end of period 11 30 — 41 Gross medical claims payable, end of period $ 3,633 $ 8,958 $ 230 $ 12,821 At June 30, 2021, the total of net incurred but not reported liabilities plus expected development on reported claims for the Commercial & Specialty Business was $71, $486 and $3,065 for the claim years 2019 and prior, 2020 and 2021, respectively. At June 30, 2021, the total of net incurred but not reported liabilities plus expected development on reported claims for the Government Business was $105, $862 and $7,961 for the claim years 2019 and prior, 2020 and 2021, respectively. At June 30, 2021, the total of net incurred but not reported liabilities plus expected development on reported claims for Other was $0, $25 and $205 for the claim years 2019 and prior, 2020 and 2021, respectively. A reconciliation of the beginning and ending balances for medical claims payable, by segment (see Note 15, “Segment Information”), for the six months ended June 30, 2020 is as follows: Commercial Government Other Total Gross medical claims payable, beginning of period $ 3,039 $ 5,608 $ — $ 8,647 Ceded medical claims payable, beginning of period (14) (19) — (33) Net medical claims payable, beginning of period 3,025 5,589 — 8,614 Business combinations and purchase adjustments — 141 198 339 Net incurred medical claims: Current period 11,318 28,162 498 39,978 Prior periods redundancies (374) (326) — (700) Total net incurred medical claims 10,944 27,836 498 39,278 Net payments attributable to: Current period medical claims 9,014 22,115 496 31,625 Prior periods medical claims 2,218 4,823 — 7,041 Total net payments 11,232 26,938 496 38,666 Net medical claims payable, end of period 2,737 6,628 200 9,565 Ceded medical claims payable, end of period 62 28 — 90 Gross medical claims payable, end of period $ 2,799 $ 6,656 $ 200 $ 9,655 The favorable development recognized in the six months ended June 30, 2021 and 2020 resulted primarily from trend factors in late 2020 and late 2019, respectively, developing more favorably than originally expected. Favorable development in the completion factors resulting from the latter parts of 2020 and 2019, respectively, developing faster than expected also contributed to the favorability. The impact from COVID-19 on healthcare utilization and medical claims submission patterns continues to provide increased estimation uncertainty on our incurred but not reported liability at June 30, 2021. The reconciliation of net incurred medical claims to benefit expense included in our consolidated statements of income for periods in 2021 is as follows: Three Months Ended Six Months Ended March 31, 2021 June 30, 2021 Net incurred medical claims: Commercial & Specialty Business $ 6,072 $ 6,718 $ 12,790 Government Business 16,319 16,723 33,042 Other 336 403 739 Total net incurred medical claims 22,727 23,844 46,571 Quality improvement and other claims expense 972 919 1,891 Benefit expense $ 23,699 $ 24,763 $ 48,462 The reconciliation of net incurred medical claims to benefit expense included in our consolidated statements of income for periods in 2020 is as follows: Three Months Ended Six Months Ended March 31, 2020 June 30, 2020 Net incurred medical claims: Commercial & Specialty Business $ 5,797 $ 5,147 $ 10,944 Government Business 14,603 13,233 27,836 Other 130 368 498 Total net incurred medical claims 20,530 18,748 39,278 Quality improvement and other claims expense 959 799 1,758 Benefit expense $ 21,489 $ 19,547 $ 41,036 The reconciliation of the medical claims payable reflected in the tables above to the consolidated ending balance for medical claims payable included in the consolidated balance sheet, as of June 30, 2021, is as follows: Commercial Government Other Total Net medical claims payable, end of period $ 3,622 $ 8,928 $ 230 $ 12,780 Ceded medical claims payable, end of period 11 30 — 41 Insurance lines other than short duration — 255 — 255 Gross medical claims payable, end of period $ 3,633 $ 9,213 $ 230 $ 13,076

Debt

Debt	6 Months Ended
	Jun. 30, 2021
Debt Disclosure [Abstract]
Debt	Debt We generally issue senior unsecured notes for long-term borrowing purposes. At June 30, 2021 and December 31, 2020, we had $22,414 and $19,652, respectively, outstanding under these notes. On May 15, 2021, we redeemed the $700 outstanding principal balance of our 3.700% Notes due August 15, 2021 at a redemption price equal to 100% of the aggregate principal amount of the notes being redeemed, plus accrued and unpaid interest. On March 17, 2021, we issued $500 aggregate principal amount of 0.450% Notes due 2023 (the “2023 Notes”), $750 aggregate principal amount of 1.500% Notes due 2026 (the “2026 Notes”), $1,000 aggregate principal amount of 2.550% Notes due 2031 (the “2031 Notes”) and $1,250 aggregate principal amount of 3.600% Notes due 2051 (the “2051 Notes”) under our shelf registration statement. Interest on the 2023 Notes, 2026 Notes, 2031 Notes and 2051 Notes is payable semi-annually in arrears on March 15 and September 15 of each year, commencing September 15, 2021. We intend to use the net proceeds for working capital and general corporate purposes, including, but not limited to, the funding of acquisitions, repayment of short-term and long-term debt and the repurchase of our common stock pursuant to our share repurchase program. We have an unsecured surplus note with an outstanding principal balance of $25 at both June 30, 2021 and December 31, 2020. We have a senior revolving credit facility (the “5-Year Facility”) with a group of lenders for general corporate purposes. The 5-Year Facility provides credit up to $2,500 and matures in June 2024. On June 3, 2021, we terminated our 364-day senior revolving credit facility (the “prior 364-Day Facility”), which was scheduled to mature in June 2021, and entered into a new 364-day senior revolving credit facility (the “new 364-Day Facility” and together with the 5-Year Facility, the “Credit Facilities” ) with a group of lenders for general corporate purposes. The new 364-Day Facility provides for credit in the amount of $1,000 and matures in June 2022. Our ability to borrow under these Credit Facilities is subject to compliance with certain covenants, including covenants requiring us to maintain a defined debt-to-capital ratio of not more than 60%, subject to increase in certain circumstances set forth in the applicable credit agreement. As of June 30, 2021, our debt-to-capital ratio, as defined and calculated under the Credit Facilities, was 39.9%. We do not believe the restrictions contained in any of our Credit Facility covenants materially affect our financial or operating flexibility. As of June 30, 2021, we were in compliance with all of the debt covenants under these Credit Facilities. There were no amounts outstanding under the prior 364-Day Facility or the new 364-Day Facility at any time during the six months ended June 30, 2021 or the year ended December 31, 2020. At June 30, 2021 and December 31, 2020, there were no amounts outstanding under our 5-Year Facility. Through certain subsidiaries, we have entered into multiple 364-day lines of credit (the “Subsidiary Credit Facilities”) with separate lenders for general corporate purposes. The Subsidiary Credit Facilities provide combined credit of up to $300. At June 30, 2021 and December 31, 2020, there were no amounts outstanding under our Subsidiary Credit Facilities. We have an authorized commercial paper program of up to $3,500, the proceeds of which may be used for general corporate purposes. At June 30, 2021 and December 31, 2020, we had $550 and $250, respectively, outstanding under this program. We have outstanding senior unsecured convertible debentures due 2042 (the “Debentures”), which are governed by an indenture (the “indenture”) between us and The Bank of New York Mellon Trust Company, N.A., as trustee. We have accounted for the Debentures in accordance with the FASB cash conversion guidance for debt with conversion and other options. As a result, the value of the embedded conversion option (net of deferred taxes and equity issuance costs) has been bifurcated from its debt host and recorded as a component of additional paid-in capital in our consolidated balance sheets. During each of the three and six months ended June 30, 2021, $46 of aggregate principal amount of the Debentures were surrendered for conversion by certain holders in accordance with the terms and provisions of the indenture. We elected to settle the excess of the principal amount of the conversions with cash for total payments during the three and six months ended June 30, 2021 of $252 and $253, respectively. We recognized a loss on the extinguishment of debt related to the Debentures of $5, for each of the three and six months ended June 30, 2021, based on the fair values of the debt on the conversion settlement dates. The following table summarizes at June 30, 2021 the related balances, conversion rate and conversion price of the Debentures: Outstanding principal amount $ 113 Unamortized debt discount $ 35 Net debt carrying amount $ 78 Equity component carrying amount $ 41 Conversion rate (shares of common stock per $1,000 of principal amount) 14.1462 Effective conversion price (per $1,000 of principal amount) $ 70.6904 We are a member, through certain subsidiaries, of the Federal Home Loan Bank of Indianapolis, the Federal Home Loan Bank of Cincinnati, the Federal Home Loan Bank of Atlanta and the Federal Home Loan Bank of New York (collectively, the “FHLBs”). As a member, we have the ability to obtain short-term cash advances, subject to certain minimum collateral requirements. We had $175 and $0 of outstanding short-term borrowings from the FHLBs at June 30, 2021 and December 31, 2020, respectively. All debt is a direct obligation of Anthem, Inc., except for the surplus note, the FHLB borrowings, and the Subsidiary Credit Facilities.

Commitments And Contingencies

Commitments And Contingencies	6 Months Ended
	Jun. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	Commitments and Contingencies Litigation and Regulatory Proceedings In the ordinary course of business, we are defendants in, or parties to, a number of pending or threatened legal actions or proceedings. To the extent a plaintiff or plaintiffs in the following cases have specified in their complaint or in other court filings the amount of damages being sought, we have noted those alleged damages in the descriptions below. With respect to the cases described below, we contest liability and/or the amount of damages in each matter and believe we have meritorious defenses. Where available information indicates that it is probable that a loss has been incurred as of the date of the consolidated financial statements and we can reasonably estimate the amount of that loss, we accrue the estimated loss by a charge to income. In many proceedings, however, it is difficult to determine whether any loss is probable or reasonably possible. In addition, even where loss is possible or an exposure to loss exists in excess of the liability already accrued with respect to a previously identified loss contingency, it is not always possible to reasonably estimate the amount of the possible loss or range of loss. With respect to many of the proceedings to which we are a party, we cannot provide an estimate of the possible losses, or the range of possible losses in excess of the amount, if any, accrued, for various reasons, including but not limited to some or all of the following: (i) there are novel or unsettled legal issues presented, (ii) the proceedings are in early stages, (iii) there is uncertainty as to the likelihood of a class being certified or decertified or the ultimate size and scope of the class, (iv) there is uncertainty as to the outcome of pending appeals or motions, (v) there are significant factual issues to be resolved, and/or (vi) in many cases, the plaintiffs have not specified damages in their complaint or in court filings. For those legal proceedings where a loss is probable, or reasonably possible, and for which it is possible to reasonably estimate the amount of the possible loss or range of losses, we currently believe that the range of possible losses, in excess of established reserves is, in the aggregate, from $0 to approximately $250 at June 30, 2021. This estimated aggregate range of reasonably possible losses is based upon currently available information taking into account our best estimate of such losses for which such an estimate can be made. Blue Cross Blue Shield Antitrust Litigation We are a defendant in multiple lawsuits that were initially filed in 2012 against the BCBSA and Blue Cross and/or Blue Shield licensees (the “Blue plans”) across the country. Cases filed in twenty-eight states were consolidated into a single, multi-district proceeding captioned In re Blue Cross Blue Shield Antitrust Litigation that is pending in the United States District Court for the Northern District of Alabama (the “Court”). Generally, the suits allege that the BCBSA and the Blue plans have conspired to horizontally allocate geographic markets through license agreements, best efforts rules that limit the percentage of non-Blue revenue of each plan, restrictions on acquisitions, rules governing the BlueCard ® and National Accounts programs and other arrangements in violation of the Sherman Antitrust Act (“Sherman Act”) and related state laws. The cases were brought by two putative nationwide classes of plaintiffs, health plan subscribers and providers. In response to cross motions for partial summary judgment by plaintiffs and defendants, the Court issued an order in April 2018 determining that the defendants’ aggregation of geographic market allocations and output restrictions are to be analyzed under a per se standard of review, and the BlueCard ® program and other alleged Section 1 Sherman Act violations are to be analyzed under the rule of reason standard of review. The Court also found that there remain genuine issues of material fact as to whether the defendants operate as a single entity with regard to the enforcement of the Blue Cross Blue Shield trademarks. In April 2019, the plaintiffs filed motions for class certification, which defendants opposed. The BCBSA and Blue plans have approved a settlement agreement and release (the “Subscriber Settlement Agreement”) with the subscriber plaintiffs. If approved by the Court, the Subscriber Settlement Agreement will require the defendants to make a monetary settlement payment, our portion of which is estimated to be $594, and will contain certain non-monetary terms including (i) eliminating the “national best efforts” rule in the BCBSA license agreements (which rule limits the percentage of non-Blue revenue permitted for each Blue plan) and (ii) allowing for some large national employers with self-funded benefit plans to request a bid for insurance coverage from a second Blue plan in addition to their local Blue plan. As of June 30, 2021, the liability balance accrued for our estimated remaining payment obligation was $507, net of payments made. In November 2020, the Court issued an order preliminarily approving the Subscriber Settlement Agreement, following which members of the subscriber class were provided notice of the Subscriber Settlement Agreement and an opportunity to opt out of the class. All terms of the Subscriber Settlement Agreement are subject to final approval by the Court. Objections to the settlement, as well as the deadline for those who wish to opt out from the settlement, must be submitted by July 28, 2021. Claims for settlement payments by members of the subscriber class must be filed by November 5, 2021. A final approval hearing has been scheduled for October 20, 2021. If the Court grants approval of the Subscriber Settlement Agreement, and after all appellate rights have expired or have been exhausted in a manner that affirms the Court’s final order and judgment, the defendants’ payment and non-monetary obligations under the Subscriber Settlement Agreement will become effective. I n October 2020, after the Court lifted the stay as to the provider litigation, provider plaintiffs filed a renewed motion for class certification, which defendants opposed. In March 2021, the Court issued an order terminating the pending motion for class certification until the Court determines the standard of review applicable to providers’ claims. In May 2021, the defendants and provider plaintiffs filed renewed standard of review motions. In June 2021, the parties filed summary judgment motions not critically dependent on class certification. Responses to the June 2021 motions are due in August 2021 and replies must be filed in September 2021. We intend to continue to vigorously defend the provider suit; however, its ultimate outcome cannot be presently determined. Blue Cross of California Taxation Litigation In July 2013, our California affiliate Blue Cross of California (doing business as Anthem Blue Cross) (“BCC”) was named as a defendant in a California taxpayer action filed in Los Angeles County Superior Court (the “Superior Court”) captioned Michael D. Myers v. State Board of Equalization, et al. This action was brought under a California statute that permits an individual taxpayer to sue a governmental agency when the taxpayer believes the agency has failed to enforce governing law. Plaintiff contends that BCC, a licensed Health Care Service Plan, is an “insurer” for purposes of taxation despite acknowledging it is not an “insurer” under regulatory law. At the time, under California law, “insurers” were required to pay a gross premiums tax (“GPT”) calculated as 2.35% on gross premiums. As a licensed Health Care Service Plan, BCC has paid the California Corporate Franchise Tax (“CFT”), the tax paid by California businesses generally. Plaintiff contends that BCC must pay the GPT rather than the CFT, and seeks a writ of mandate directing the taxing agencies to collect the GPT and an order requiring BCC to pay GPT back taxes, interest, and penalties for the eight-year period prior to the filing of the complaint. Because the GPT is constitutionally imposed in lieu of certain other taxes, BCC has filed protective tax refund claims with the City of Los Angeles, the California Department of Health Care Services and the Franchise Tax Board to protect its rights to recover certain taxes previously paid should BCC eventually be determined to be subject to the GPT for the tax periods at issue in the litigation. In March 2018, the Superior Court denied BCC’s motion for judgment on the pleadings and similar motions brought by other entities. BCC filed a motion for summary judgment with the Superior Court, which was heard in October 2020. In December 2020, the Superior Court granted BCC’s motion for summary judgment, dismissing the plaintiff’s lawsuit. Plaintiff has appealed the order granting summary judgment. We estimate that the briefing on the appeal will be complete by the end of 2021 and that oral argument will be scheduled sometime in 2022. We intend to vigorously defend the appeal of this lawsuit. Express Scripts, Inc. Pharmacy Benefit Management Litigation In March 2016, we filed a lawsuit against Express Scripts, Inc. (“Express Scripts”), our vendor at the time for PBM services, captioned Anthem, Inc. v. Express Scripts, Inc. , in the U.S. District Court for the Southern District of New York. The lawsuit seeks to recover over $14,800 in damages for pharmacy pricing that is higher than competitive benchmark pricing under the agreement between the parties (the “ESI PBM Agreement”), over $158 in damages related to operational breaches, as well as various declarations under the ESI PBM Agreement, including that Express Scripts: (i) breached its obligation to negotiate in good faith and to agree in writing to new pricing terms; (ii) was required to provide competitive benchmark pricing to us through the term of the ESI PBM Agreement; (iii) has breached the ESI PBM Agreement; and (iv) is required under the ESI PBM Agreement to provide post-termination services, at competitive benchmark pricing, for one year following any termination. Express Scripts has disputed our contractual claims and is seeking declaratory judgments: (i) regarding the timing of the periodic pricing review under the ESI PBM Agreement, and (ii) that it has no obligation to ensure that we receive any specific level of pricing, that we have no contractual right to any change in pricing under the ESI PBM Agreement and that its sole obligation is to negotiate proposed pricing terms in good faith. In the alternative, Express Scripts claims that we have been unjustly enriched by its payment of $4,675 at the time we entered into the ESI PBM Agreement. In March 2017, the court granted our motion to dismiss Express Scripts’ counterclaims for (i) breach of the implied covenant of good faith and fair dealing and (ii) unjust enrichment with prejudice. The only remaining claims are for breach of contract and declaratory relief. Rebuttal expert reports were submitted in October 2020 and discovery must be completed by July 2021. We intend to vigorously pursue our claims and defend against any counterclaims, which we believe are without merit; however, the ultimate outcome cannot be presently determined. In re Express Scripts/Anthem ERISA Litigation We are a defendant in a class action lawsuit that was initially filed in June 2016 against Anthem, Inc. and Express Scripts, which has been consolidated into a single multi-district lawsuit captioned In re Express Scripts/Anthem ERISA Litigation, in the U.S. District Court for the Southern District of New York. The consolidated complaint was filed by plaintiffs against Express Scripts and us on behalf of all persons who are participants in or beneficiaries of any ERISA or non-ERISA healthcare plan from December 1, 2009 to December 31, 2019 in which we provided prescription drug benefits through the ESI PBM Agreement and paid a percentage based co-insurance payment in the course of using that prescription drug benefit. The plaintiffs allege that we breached our duties, either under ERISA or with respect to the implied covenant of good faith and fair dealing implied in the health plans, (i) by failing to adequately monitor Express Scripts’ pricing under the ESI PBM Agreement, (ii) by placing our own pecuniary interest above the best interests of our insureds by allegedly agreeing to higher pricing in the ESI PBM Agreement in exchange for the purchase price for our NextRx PBM business, and (iii) with respect to the non-ERISA members, by negotiating and entering into the ESI PBM Agreement that was allegedly detrimental to the interests of such non-ERISA members. Plaintiffs seek to hold us and Express Scripts jointly and severally liable and to recover all losses allegedly suffered by the proposed class, equitable relief, disgorgement of alleged ill-gotten gains, injunctive relief, attorney’s fees and costs and interest. In April 2017, we filed a motion to dismiss the claims brought against us, and it was granted, without prejudice, in January 2018. Plaintiffs filed a notice of appeal with the United States Court of Appeals for the Second Circuit (the “Second Circuit”), which was heard in October 2018. In December 2020, the Second Circuit affirmed the trial court’s decision dismissing the ERISA complaint. Plaintiffs filed a Petition for Rehearing and Rehearing En Banc. Plaintiff’s Petition for Rehearing was denied. Plaintiffs filed a Writ of Certiorari with the U.S. Supreme Court, our response to which is due in August 2021. We intend to vigorously defend this suit; however, its ultimate outcome cannot be presently determined. Cigna Corporation Merger Litigation In July 2015, we and Cigna Corporation (“Cigna”) announced that we entered into the Cigna Agreement and Plan of Merger (“Cigna Merger Agreement”) pursuant to which we would acquire all outstanding shares of Cigna. In July 2016, the U.S. Department of Justice (“DOJ”), along with certain state attorneys general, filed a civil antitrust lawsuit in the U.S. District Court for the District of Columbia (“District Court”) seeking to block the merger. In February 2017, Cigna purported to terminate the Cigna Merger Agreement and commenced litigation against us in the Delaware Court of Chancery (“Delaware Court”) seeking damages, including the $1,850 termination fee pursuant to the terms of the Cigna Merger Agreement, and a declaratory judgment that its purported termination of the Cigna Merger Agreement was lawful, among other claims, which is captioned Cigna Corp. v. Anthem Inc. Also in February 2017, we initiated our own litigation against Cigna in the Delaware Court seeking a temporary restraining order to enjoin Cigna from terminating the Cigna Merger Agreement, specific performance compelling Cigna to comply with the Cigna Merger Agreement and damages, which is captioned Anthem Inc. v. Cigna Corp . In April 2017, the U.S. Circuit Court of Appeals for the District of Columbia affirmed the ruling of the District Court, which blocked the merger. In May 2017, after the Delaware Court denied our motion to enjoin Cigna from terminating the Cigna Merger Agreement, we delivered to Cigna a notice terminating the Cigna Merger Agreement. In the Delaware Court litigation, trial commenced in late February 2019 and concluded in March 2019. The Delaware Court held closing arguments in November 2019 and took the matter under consideration. In August 2020, the Delaware Court issued an opinion finding that neither party was owed damages and that we did not owe Cigna the $1,850 termination fee. The Delaware Court issued an order implementing its opinion in October 2020. Cigna filed its notice of appeal in November 2020 challenging the Court’s decision that Anthem did not owe Cigna a termination fee. In May 2021, the Delaware Supreme Court affirmed the trial court's decision. This matter is now concluded. In October 2018, a shareholder filed a derivative lawsuit in the State of Indiana Marion County Superior Court (the “Marion County Superior Court”), captioned Henry Bittmann, Derivatively, et al. v. Joseph R Swedish, et al. , purportedly on behalf of us and our shareholders against certain current and former directors and officers alleging breaches of fiduciary duties, unjust enrichment and corporate waste associated with the Cigna Merger Agreement. This case had been stayed at the request of the parties pending the outcome of our litigation with Cigna in the Delaware Court. In May 2021, the Delaware Supreme Court affirmed the trial court’s decision. As a result of this development, the parties to this derivative lawsuit stipulated to the dismissal of this lawsuit, which the Marion County Superior Court approved in May 2021. This matter is now concluded. Medicare Risk Adjustment Litigation In March 2020, the DOJ filed a civil lawsuit against Anthem, Inc. in the U.S. District Court for the Southern District of New York in a case captioned United States v. Anthem, Inc . The DOJ’s suit alleges, among other things, that we falsely certified the accuracy of the diagnosis data we submitted to the Centers for Medicare and Medicaid Services (“CMS”) for risk-adjustment purposes under Medicare Part C and knowingly failed to delete inaccurate diagnosis codes. The DOJ further alleges that, as a result of these purported acts, we caused CMS to calculate the risk-adjustment payments based on inaccurate diagnosis information, which enabled us to obtain unspecified amounts of payments in Medicare funds in violation of the False Claims Act. The DOJ filed an amended complaint in July 2020, alleging the same causes of action but revising some of its allegations. In September 2020, we filed a motion to transfer the lawsuit to the Southern District of Ohio, a motion to dismiss part of the lawsuit, and a motion to strike certain allegations in the amended complaint. The motions are fully briefed and no decision has been rendered. We intend to continue to vigorously defend this suit; however, the ultimate outcome cannot be presently determined. Investigations of CareMore and HealthSun With the assistance of outside counsel, we are conducting investigations of risk-adjustment practices involving data submitted to CMS (unrelated to our retrospective chart review program) at CareMore Health Plans, Inc. (“CareMore”), one of our California subsidiaries, and HealthSun Health Plans, Inc. (“HealthSun”), one of our Florida subsidiaries. Our CareMore investigation has resulted in the termination of CareMore’s relationship with one contracted provider in California. Our HealthSun investigation focuses on risk adjustment practices initiated prior to our acquisition of HealthSun in December 2017 that continued after the acquisition. We have voluntarily self-disclosed the existence of both of our investigations to CMS and the Criminal Division of the DOJ, which then initiated an investigation. We are cooperating with the government’s investigation. We are in the process of analyzing the scope of potential data corrections to be submitted to CMS. We have also asserted indemnity claims for escrowed funds under the HealthSun purchase agreement for, among other things, breach of healthcare and financial representation provisions, based on the conduct discovered during our investigation. We are in active litigation with two groups of sellers regarding part of the escrowed funds in cases captioned Shareholder Representative Services, LLC v. ATH Holding Company, LLC and Highland Acquisition Holdings, LLC and LPPAS Representative, LLC v. ATH Holding Company, LLC, both pending in the Delaware Court. Other Contingencies From time to time, we and certain of our subsidiaries are parties to various legal proceedings, many of which involve claims for coverage encountered in the ordinary course of business. We, like HMOs and health insurers generally, exclude certain healthcare and other services from coverage under our HMO, PPO and other plans. We are, in the ordinary course of business, subject to the claims of our enrollees arising out of decisions to restrict or deny reimbursement for uncovered services. The loss of even one such claim, if it results in a significant punitive damage award, could have a material adverse effect on us. In addition, the risk of potential liability under punitive damage theories may increase significantly the difficulty of obtaining reasonable reimbursement of coverage claims. In addition to the lawsuits described above, we are also involved in other pending and threatened litigation of the character incidental to our business, and are from time to time involved as a party in various governmental investigations, audits, reviews and administrative proceedings. These investigations, audits, reviews and administrative proceedings include routine and special inquiries by state insurance departments, state attorneys general, the U.S. Attorney General and subcommittees of the U.S. Congress. Such investigations, audits, reviews and administrative proceedings could result in the imposition of civil or criminal fines, penalties, other sanctions and additional rules, regulations or other restrictions on our business operations. Any liability that may result from any one of these actions, or in the aggregate, could have a material adverse effect on our consolidated financial position or results of operations. Contractual Obligations and Commitments In March 2020, we entered into an agreement with a vendor for information technology infrastructure and related management and support services through June 2025. The new agreement supersedes certain prior agreements for such services and includes provisions for additional services not provided under those agreements. Our remaining commitment under this agreement at June 30, 2021 is approximately $1,166. We will have the ability to terminate the agreement upon the occurrence of certain events, subject to early termination fees.

Capital Stock

Capital Stock	6 Months Ended
	Jun. 30, 2021
Banking Regulation, Total Capital [Abstract]
Capital Stock	Capital Stock Use of Capital – Dividends and Stock Repurchase Program We regularly review the appropriate use of capital, including acquisitions, common stock and debt security repurchases and dividends to shareholders. The declaration and payment of any dividends or repurchases of our common stock or debt is at the discretion of our Board of Directors and depends upon our financial condition, results of operations, future liquidity needs, regulatory and capital requirements and other factors deemed relevant by our Board of Directors. A summary of our cash dividend activity for the six months ended June 30, 2021 and 2020 is as follows: Declaration Date Record Date Payment Date Cash Dividend per Share Total Six Months Ended June 30, 2021 January 26, 2021 March 10, 2021 March 25, 2021 $1.13 $ 277 April 20, 2021 June 10, 2021 June 25, 2021 $1.13 $ 278 Six Months Ended June 30, 2020 January 28, 2020 March 16, 2020 March 27, 2020 $0.95 $ 240 April 28, 2020 June 10, 2020 June 25, 2020 $0.95 $ 242 On July 20, 2021, our Audit Committee declared a third quarter 2021 dividend to shareholders of $1.13 per share, payable on September 24, 2021 to shareholders of record at the close of business on September 10, 2021. Under our Board of Directors’ authorization, we maintain a common stock repurchase program. On January 26, 2021, our Audit Committee, pursuant to authorization granted by the Board of Directors, authorized a $5,000 increase to the common stock repurchase program. Repurchases may be made from time to time at prevailing market prices, subject to certain restrictions on volume, pricing and timing. The repurchases are effected from time to time in the open market, through negotiated transactions, including accelerated share repurchase agreements, and through plans designed to comply with Rule 10b5-1 under the Securities Exchange Act of 1934, as amended. Our stock repurchase program is discretionary, as we are under no obligation to repurchase shares. We repurchase shares under the program when we believe it is a prudent use of capital. The excess cost of the repurchased shares over par value is charged on a pro rata basis to additional paid-in capital and retained earnings. A summary of common stock repurchases for the six months ended June 30, 2021 and 2020 is as follows: Six Months Ended June 30 2021 2020 Shares repurchased 2.7 2.1 Average price per share $ 346.47 $ 273.72 Aggregate cost $ 927 $ 584 Authorization remaining at the end of the period $ 5,165 $ 3,208 For additional information regarding the use of capital for debt security repurchases, see Note 10, “Debt,” included in this Form 10-Q and Note 13, “Debt,” to our audited consolidated financial statements as of and for the year ended December 31, 2020 included in our 2020 Annual Report on Form 10-K. Stock Incentive Plan s A summary of stock option activity for the six months ended June 30, 2021 is as follows: Number of Weighted- Weighted- Aggregate Outstanding at January 1, 2021 3.1 $ 230.00 Granted 0.7 312.33 Exercised (0.6) 193.55 Forfeited or expired (0.1) 286.70 Outstanding at June 30, 2021 3.1 253.91 7.23 $ 402 Exercisable at June 30, 2021 1.6 215.56 5.94 $ 270 A summary of the nonvested restricted stock activity, including restricted stock units, for the six months ended June 30, 2021 is as follows: Restricted Weighted- Nonvested at January 1, 2021 1.3 $ 272.51 Granted 0.9 312.50 Vested (0.8) 244.24 Forfeited (0.1) 287.67 Nonvested at June 30, 2021 1.3 295.57 During the six months ended June 30, 2021, we granted approximately 0.3 restricted stock units that are contingent upon us achieving earnings targets over the three year period from 2021 to 2023. These grants have been included in the activity shown above, but will be subject to adjustment at the end of 2023 based on results in the three year period. During the six months ended June 30, 2021, we granted an additional 0.3 restricted stock units associated with our 2018 grants that were earned as a result of satisfactory completion of performance measures between 2018 and 2020. These grants and vested shares have been included in the activity shown above. Fair Value We use a binomial lattice valuation model to estimate the fair value of all stock options granted. For a more detailed discussion of our stock incentive plan fair value methodology, see Note 15, “Capital Stock,” to our audited consolidated financial statements as of and for the year ended December 31, 2020 included in our 2020 Annual Report on Form 10-K. The following weighted-average assumptions were used to estimate the fair values of options granted during the six months ended June 30, 2021 and 2020: Six Months Ended June 30 2021 2020 Risk-free interest rate 1.44 % 1.30 % Volatility factor 30.00 % 26.00 % Quarterly dividend yield 0.360 % 0.350 % Weighted-average expected life (years) 5.50 4.30 The following weighted-average fair values per option or share were determined for the six months ended June 30, 2021 and 2020: Six Months Ended June 30 2021 2020 Options granted during the period $ 79.22 $ 54.04 Restricted stock awards granted during the period 312.50 272.14

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	6 Months Ended
	Jun. 30, 2021
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss A reconciliation of the components of accumulated other comprehensive loss at June 30, 2021 and 2020 is as follows: June 30 2021 2020 Investments: Gross unrealized gains $ 1,095 $ 974 Gross unrealized losses (89) (229) Net pre-tax unrealized gains 1,006 745 Deferred tax liability (240) (183) Adjustment for noncontrolling interest (4) — Net unrealized gains on investments 762 562 Non-credit components of impairments on investments: Gross unrealized losses — (32) Deferred tax asset — 8 Net unrealized non-credit component of impairments on investments — (24) Cash flow hedges: Gross unrealized losses (308) (323) Deferred tax asset 64 67 Net unrealized losses on cash flow hedges (244) (256) Defined benefit pension plans: Deferred net actuarial loss (723) (707) Deferred prior service credits — (1) Deferred tax asset 184 181 Net unrecognized periodic benefit costs for defined benefit pension plans (539) (527) Postretirement benefit plans: Deferred net actuarial loss (3) (25) Deferred prior service costs 10 16 Deferred tax (liability) asset (2) 2 Net unrecognized periodic benefit credit (costs) for postretirement benefit plans 5 (7) Foreign currency translation adjustments: Gross unrealized losses (1) (3) Deferred tax asset — 1 Net unrealized losses on foreign currency translation adjustments (1) (2) Accumulated other comprehensive loss $ (17) $ (254) Other comprehensive income (loss) reclassification adjustments for the three months ended June 30, 2021 and 2020 are as follows: Three Months Ended June 30 2021 2020 Investments: Net holding gains on investment securities arising during the period, net of tax expense of ($61) and ($238), respectively $ 201 $ 741 Reclassification adjustment for net realized gains on investment securities, net of tax expense of $7 and $4, respectively (26) (11) Total reclassification adjustment on investments 175 730 Non-credit component of impairments on investments: Non-credit component of impairments on investments, net of tax expense of $0 and ($2), respectively 1 10 Cash flow hedges: Holding gain, net of tax expense of ($1) and ($1), respectively 2 3 Other: Net change in unrecognized periodic benefit costs for defined benefit pension and postretirement benefit plans, net of tax expense of ($2) and ($4), respectively 8 10 Foreign currency translation adjustment, net of tax benefit of $1 and $0, respectively (6) 1 Net gain recognized in other shareholders’ comprehensive income, net of tax expense of ($56) and ($241), respectively 180 754 Net loss related to noncontrolling interests, net of tax benefit of $1 and $0, respectively (2) — Net gain recognized in other comprehensive income, net of tax expense of ($55) and ($241), respectively $ 178 $ 754 Other comprehensive income (loss) reclassification adjustments for the six months ended June 30, 2021 and 2020 are as follows: Six Months Ended June 30 2021 2020 Investments: Net holding (loss) gains on investment securities arising during the period, net of tax benefit (expense) of $46 and ($23), respectively $ (125) $ 33 Reclassification adjustment for net realized (loss) gains on investment securities, net of tax expense (benefit) of $16 and ($5), respectively (62) 8 Total reclassification adjustment on investments (187) 41 Non-credit component of impairments on investments: Non-credit component of impairments on investments, net of tax (expense) benefit of ($1) and $7, respectively 2 (22) Cash flow hedges: Holding gain, net of tax expense of ($2) and ($2), respectively 6 6 Other: Net change in unrecognized periodic benefit costs for defined benefit pension and postretirement benefit plans, net of tax expense of ($6) and ($7), respectively 18 17 Foreign currency translation adjustment, net of tax benefit of $1 and $0, respectively (6) — Net (loss) gain recognized in other shareholders’ comprehensive income, net of tax benefit (expense) of $54 and ($30), respectively (167) 42 Net loss related to noncontrolling interests, net of tax benefit of $1 and $0, respectively — — Net (loss) gain recognized in other comprehensive income, net of tax benefit (expense) of $55 and ($30), respectively $ (167) $ 42

Earnings Per Share

Earnings Per Share	6 Months Ended
	Jun. 30, 2021
Earnings Per Share [Abstract]
Earnings Per Share	Earnings per Share The denominator for basic and diluted earnings per share for the three and six months ended June 30, 2021 and 2020 is as follows: Three Months Ended Six Months Ended 2021 2020 2021 2020 Denominator for basic earnings per share – weighted-average shares 244.5 252.2 244.8 252.3 Effect of dilutive securities – employee stock options, nonvested restricted stock awards and convertible debentures 2.9 3.2 3.0 3.6 Denominator for diluted earnings per share 247.4 255.4 247.8 255.9 During the three months ended June 30, 2021 and 2020, weighted-average shares related to certain stock options of 0.3 and 1.6, respectively, were excluded from the denominator for diluted earnings per share because the stock options were anti-dilutive. During the six months ended June 30, 2021 and 2020, weighted-average shares related to certain stock options of 0.4 and 1.3, respectively, were excluded from the denominator for diluted earnings per share because the stock options were anti-dilutive. During the three and six months ended June 30, 2021, we issued approximately 0.0 and 0.9 restricted stock units, respectively, under our stock incentive plans, 0.3 of which vesting is contingent upon us meeting specified annual earnings targets for the three year period of 2021 through 2023. During the three and six months ended June 30, 2020, we issued approximately 0.1 and 1.3 restricted stock units, respectively, under our stock incentive plans, 0.2 of which vesting is contingent upon us meeting specified annual earnings targets for the three year period of 2020 through 2022. The contingent restricted stock units have been excluded from the denominator for diluted earnings per share and will be included only if and when the contingency is met.

Segment Information

Segment Information	6 Months Ended
	Jun. 30, 2021
Segment Reporting [Abstract]
Segment Information	Segment Information The results of our operations are described through four reportable segments: Commercial & Specialty Business, Government Business, IngenioRx and Other. Our Commercial & Specialty Business segment offers plans and services to our Individual, Group risk-based, Group fee-based, BlueCard, and Specialty customers. The Commercial & Specialty Business segment offers health products on a full-risk basis; provides a broad array of managed care services to fee-based customers, including claims processing, underwriting, stop loss insurance, actuarial services, provider network access, medical cost management, disease management, wellness programs and other administrative services; and provides an array of specialty and other insurance products and services such as dental, vision, life and disability insurance benefits. Our Government Business segment includes our Medicare and Medicaid businesses, National Government Services (“NGS”), and services provided to the federal government in connection with the FEHB program. Our Medicare business includes services such as Medicare Supplement plans; Medicare Advantage, including Special Needs Plans; Medicare Part D; and dual-eligible programs through Medicare-Medicaid Plans. Medicare Advantage membership also includes Medicare Advantage members in our Group Retiree Solutions business who are retired members of Commercial accounts or retired members of groups who are not affiliated with our Commercial accounts who have selected a Medicare Advantage product through us. Our Medicaid business includes our managed care alternatives through publicly funded healthcare programs, including Medicaid, Medicaid expansion programs related to the Patient Protection and Affordable Care Act and the Health Care and Education Reconciliation Act of 2010, as amended, Temporary Assistance for Needy Families programs, programs for seniors and people with disabilities, Children’s Health Insurance Programs, and specialty programs such as those focused on long-term services and support, HIV/AIDS, foster care, behavioral health and/or substance abuse disorders, and intellectual disabilities or developmental disabilities. NGS acts as a Medicare contractor for the federal government in several regions across the nation. Our IngenioRx segment includes our PBM business, which began its operations during the second quarter of 2019. IngenioRx markets and offers PBM services to our affiliated health plan customers, as well as to external customers outside of the health plans we own. IngenioRx has a comprehensive PBM services portfolio, which includes services such as formulary management, pharmacy networks, prescription drug database, member services and mail order capabilities. Our Other segment includes our Diversified Business Group (“DBG”), which is our integrated health services business, and certain eliminations and corporate expenses not allocated to our other reportable segments. Affiliated revenues represent revenues or cost for services provided by IngenioRx and DBG to our subsidiaries, are recorded at cost or management’s estimate of fair market value, and are eliminated in consolidation. Financial data by reportable segment for the three and six months ended June 30, 2021 and 2020 is as follows: Commercial Government IngenioRx Other Eliminations Total Three Months Ended June 30, 2021 Operating revenue - unaffiliated $ 9,550 $ 20,066 $ 3,042 $ 621 $ — $ 33,279 Operating revenue - affiliated — — 3,177 1,896 (5,073) — Operating gain 791 868 405 17 — 2,081 Three Months Ended June 30, 2020 Operating revenue - unaffiliated $ 8,789 $ 17,242 $ 2,544 $ 603 $ — $ 29,178 Operating revenue - affiliated — — 2,725 849 (3,574) — Operating gain 1,372 1,618 304 66 — 3,360 Six Months Ended June 30, 2021 Operating revenue - unaffiliated $ 19,041 $ 39,349 $ 5,780 $ 1,207 $ — $ 65,377 Operating revenue - affiliated — — 6,301 3,680 (9,981) — Operating gain 2,059 1,346 812 25 — 4,242 Six Months Ended June 30, 2020 Operating revenue - unaffiliated $ 18,150 $ 34,708 $ 4,887 $ 881 $ — $ 58,626 Operating revenue - affiliated — — 5,579 1,598 (7,177) — Operating gain 2,792 2,029 653 80 — 5,554 The major product revenues for each of the reportable segments for the three and six months ended June 30, 2021 and 2020 are as follows: Three Months Ended Six Months Ended 2021 2020 2021 2020 Commercial & Specialty Business Managed care products $ 7,772 $ 7,132 $ 15,461 $ 14,700 Managed care services 1,416 1,263 2,802 2,645 Dental/Vision products and services 335 284 671 599 Other 27 110 107 206 Total Commercial & Specialty Business 9,550 8,789 19,041 18,150 Government Business Managed care products 19,965 17,149 39,147 34,524 Managed care services 101 93 202 184 Total Government Business 20,066 17,242 39,349 34,708 IngenioRx Pharmacy products and services 6,219 5,269 12,081 10,466 Total IngenioRx 6,219 5,269 12,081 10,466 Other Integrated health services 2,366 1,376 4,615 2,325 Other 151 76 272 154 Total Other Business 2,517 1,452 4,887 2,479 Eliminations Eliminations (5,073) (3,574) (9,981) (7,177) Total product revenues $ 33,279 $ 29,178 $ 65,377 $ 58,626 The classification between managed care products and managed care services in the above table primarily distinguishes between the levels of risk assumed. Managed care products represent insurance products where we bear the insurance risk, whereas managed care services represent product offerings where we provide claims adjudication and other administrative services to the customer, but the customer principally bears the insurance risk. A reconciliation of reportable segments’ operating revenue to the amounts of total revenues included in our consolidated statements of income for the three and six months ended June 30, 2021 and 2020 is as follows: Three Months Ended Six Months Ended 2021 2020 2021 2020 Reportable segments’ operating revenue $ 33,279 $ 29,178 $ 65,377 $ 58,626 Net investment income 400 57 691 311 Net realized gains (losses) on financial instruments 172 29 168 (52) Total revenues $ 33,851 $ 29,264 $ 66,236 $ 58,885 A reconciliation of reportable segments’ operating gain to income before income tax expense included in our consolidated statements of income for the three and six months ended June 30, 2021 and 2020 is as follows: Three Months Ended Six Months Ended 2021 2020 2021 2020 Reportable segments’ operating gain $ 2,081 $ 3,360 $ 4,242 $ 5,554 Net investment income 400 57 691 311 Net realized gains (losses) on financial instruments 172 29 168 (52) Interest expense (205) (201) (397) (395) Amortization of other intangible assets (90) (93) (170) (176) Loss on extinguishment of debt (5) (3) (5) (4) Income before income tax expense $ 2,353 $ 3,149 $ 4,529 $ 5,238

Leases

Leases	6 Months Ended
	Jun. 30, 2021
Leases [Abstract]
Leases	Leases We lease office space and certain computer and related equipment using noncancellable operating leases. Our leases have remaining lease terms of 1 year to 13 years. The information related to our leases is as follows: Balance Sheet Location June 30, 2021 December 31, 2020 Operating Leases Right-of-use assets Other noncurrent assets $ 683 $ 646 Lease liabilities, current Other current liabilities 144 110 Lease liabilities, noncurrent Other noncurrent liabilities 833 847 Three Months Ended Six Months Ended 2021 2020 2021 2020 Lease Expense Operating lease expense $ 34 $ 59 $ 63 $ 106 Short-term lease expense 12 14 24 27 Sublease income (1) (4) (2) (7) Total lease expense $ 45 $ 69 $ 85 $ 126 Other information Operating cash paid for amounts included in the measurement of lease liabilities, operating leases $ 36 $ 46 $ 88 $ 90 Right-of-use assets obtained in exchange for new lease liabilities, operating leases $ 145 $ 33 $ 160 $ 356 As of June 30, 2021 and December 31, 2020, the weighted average remaining lease term of our operating leases was 7 years. The lease liabilities reflect a weighted average discount rate of 2.86% at June 30, 2021 and 3.21% at December 31, 2020. Future lease payments for noncancellable operating leases with initial or remaining terms of one year or more are as follows: 2021 (excluding the six months ended June 30, 2021) $ 105 2022 198 2023 175 2024 146 2025 105 Thereafter 324 Total future minimum payments 1,053 Less imputed interest (76) Total lease liabilities $ 977 As of June 30, 2021, we have additional operating leases for building spaces that have not yet commenced, and some building spaces are being constructed by the lessors and their agents. These leases have terms of up to 11 years and are expected to commence on various dates during 2021 when the construction is complete and we take possession of the buildings. The undiscounted lease payments for these leases, which are not included in the tables above, aggregate $65.

Basis of Presentation and Sig_2

Basis of Presentation and Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation: The accompanying unaudited consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial reporting. Accordingly, they do not include all of the information and footnotes required by GAAP for annual financial statements. We have omitted certain footnote disclosures that would substantially duplicate the disclosures in our 2020 Annual Report on Form 10-K, unless the information contained in those disclosures materially changed or is required by GAAP. Certain prior year amounts have been reclassified to conform to the current year presentation. In the opinion of management, all adjustments, including normal recurring adjustments, necessary for a fair statement of the consolidated financial statements as of and for the three and six months ended June 30, 2021 and 2020 have been recorded. The results of operations for the three and six months ended June 30, 2021 are not necessarily indicative of the results that may be expected for the full year ending December 31, 2021, or any other period. These unaudited consolidated financial statements should be read in conjunction with our audited consolidated financial statements as of and for the year ended December 31, 2020 included in our 2020 Annual Report on Form 10-K.
Foreign Currency	Certain of our subsidiaries operate outside of the United States and have functional currencies other than the U.S. dollar (“USD”). We translate the assets and liabilities of those subsidiaries to USD using the exchange rate in effect at the end of the period. We translate the revenues and expenses of those subsidiaries to USD using the average exchange rates in effect during the period. The net effect of these translation adjustments is included in “Foreign currency translation adjustments” in our consolidated statements of comprehensive income.
Cash and Cash Equivalents	Cash and Cash Equivalents: We control a number of bank accounts that are used exclusively to hold customer funds for the administration of customer benefits, and we have cash and cash equivalents on deposit to meet certain regulatory requirements. These amounts totaled $248 and $170 at June 30, 2021 and December 31, 2020, respectively, and are included in the cash and cash equivalents line on our consolidated balance sheets.
Investment, Policy	Investments: We classify fixed maturity securities in our investment portfolio as “available-for-sale” and report those securities at fair value. Certain fixed maturity securities are available to support current operations and, accordingly, we classify such investments as current assets without regard to their contractual maturity. Investments used to satisfy contractual, regulatory or other requirements are classified as long-term, without regard to contractual maturity. If a fixed maturity security is in an unrealized loss position and we have the intent to sell the fixed maturity security, or it is more likely than not that we will have to sell the fixed maturity security before recovery of its amortized cost basis, we write down the fixed maturity security’s cost basis to fair value and record an impairment loss in our consolidated statements of income. For impaired fixed maturity securities that we do not intend to sell or if it is more likely than not that we will not have to sell such securities, but we expect that we will not fully recover the amortized cost basis, we recognize the credit component of the impairment as an allowance for credit loss in our consolidated balance sheets and record an impairment loss in our consolidated statements of income. The non-credit component of the impairment is recognized in accumulated other comprehensive (loss) income. Furthermore, unrealized losses entirely caused by non-credit-related factors related to fixed maturity securities for which we expect to fully recover the amortized cost basis continue to be recognized in accumulated other comprehensive (loss) income. The credit component of an impairment is determined primarily by comparing the net present value of projected future cash flows with the amortized cost basis of the fixed maturity security. The net present value is calculated by discounting our best estimate of projected future cash flows at the effective interest rate implicit in the fixed maturity security at the date of purchase. For mortgage-backed and asset-backed securities, cash flow estimates are based on assumptions regarding the underlying collateral, including prepayment speeds, vintage, type of underlying asset, geographic concentrations, default rates, recoveries and changes in value. For all other securities, cash flow estimates are driven by assumptions regarding probability of default, including changes in credit ratings and estimates regarding timing and amount of recoveries associated with a default. For asset-backed securities included in fixed maturity securities, we recognize income using an effective yield based on anticipated prepayments and the estimated economic life of the securities. When estimates of prepayments change, the effective yield is recalculated to reflect actual payments to date and anticipated future payments. The net investment in the securities is adjusted to the amount that would have existed had the new effective yield been applied since the purchase date of the securities. Such adjustments are reported within net investment income. The changes in fair value of our marketable equity securities are recognized in our results of operations within net realized gains and losses on financial instruments. Certain marketable equity securities are held to satisfy contractual obligations, and are reported under the caption “Other invested assets” in our consolidated balance sheets. We have corporate-owned life insurance policies on certain participants in our deferred compensation plans and other members of management. The cash surrender value of the corporate-owned life insurance policies is reported under the caption “Other invested assets” in our consolidated balance sheets. We use the equity method of accounting for investments in companies in which our ownership interest may enable us to influence the operating or financial decisions of the investee company. Our proportionate share of equity in net income of these unconsolidated affiliates is reported within net investment income. The equity method investments are reported under the caption “Other invested assets” in our consolidated balance sheets. Investment income is recorded when earned. All securities sold resulting in investment gains and losses are recorded on the trade date. Realized gains and losses are determined on the basis of the cost or amortized cost of the specific securities sold. We participate in securities lending programs whereby marketable securities in our investment portfolio are transferred to independent brokers or dealers in exchange for cash and securities collateral. We recognize the collateral as an asset, which is reported under the caption “Other current assets” in our consolidated balance sheets, and we record a corresponding liability for the obligation to return the collateral to the borrower, which is reported under the caption “Other current liabilities” in our consolidated balance sheets. The securities on loan are reported in the applicable investment category on our consolidated balance sheets. Unrealized gains or losses on securities lending collateral are included in accumulated other comprehensive (loss) income as a separate component of shareholders’ equity. The market value of loaned securities and that of the collateral pledged can fluctuate in non-synchronized fashions. To the extent the loaned securities’ value appreciates faster or depreciates slower than the value of the collateral pledged, we are exposed to the risk of the shortfall. As a primary mitigating mechanism, the loaned securities and collateral pledged are marked to market on a daily basis and the shortfall, if any, is collected accordingly. Secondarily, the collateral level is set at 102% of the value of the loaned securities, which provides a cushion before any shortfall arises. The investment of the cash collateral is subject to market risk, which is managed by limiting the investments to higher quality and shorter duration instruments.
Receivable	Receivables: Receivables are reported net of amounts for expected credit losses. The allowance for doubtful accounts is based on historical collection trends, future forecasts and our judgment regarding the ability to collect specific accounts. Premium receivables include the uncollected amounts from insured groups, individuals and government programs. Premium receivables are reported net of an allowance for doubtful accounts of $152 and $146 at June 30, 2021 and December 31, 2020, respectively. Self-funded receivables include administrative fees, claims and other amounts due from self-funded customers. Self-funded receivables are reported net of an allowance for doubtful accounts of $91 and $54 at June 30, 2021 and December 31, 2020, respectively. Other receivables include pharmacy rebates, provider advances, claims recoveries, reinsurance receivables, proceeds due from brokers on investment trades, accrued investment income, and other miscellaneous amounts due to us. These receivables are reported net of an allowance for doubtful accounts of $479 and $374 at June 30, 2021 and December 31, 2020, respectively.
Revenue Recognition	Revenue Recognition: For our fee-based contracts, we had no material contract assets, contract liabilities or deferred contract costs recorded on our consolidated balance sheet at June 30, 2021. For the three and six months ended June 30, 2021, revenue recognized from performance obligations related to prior periods, such as due to changes in transaction price, was not material. For contracts that have an original expected duration of greater than one year, revenue expected to be recognized in future periods related to unfulfilled contractual performance obligations and contracts with variable consideration related to undelivered performance obligations is not material.
New Accounting Pronouncements	Recently Adopted Accounting Guidance: In January 2021, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2021-01, Reference Rate Reform (Topic 848) (“ASU 2021-01”). The amendments in ASU 2021-01 provide optional expedients and exceptions for applying GAAP to contract modifications and hedging relationships, subject to meeting certain criteria, that reference the London Interbank Offered Rate (“LIBOR”) or another reference rate expected to be discontinued because of the reference rate reform. The provisions must be applied at a Topic, Subtopic, or Industry Subtopic level for all transactions other than derivatives, which may be applied at a hedging relationship level. We adopted ASU 2021-01 on January 7, 2021 and the adoption did not have an impact on our consolidated financial position, results of operations or cash flows. In October 2020, the FASB issued Accounting Standards Update No. 2020-08, Codification Improvements to Subtopic 310-20, Receivables—Nonrefundable Fees and Other Costs (“ASU 2020-08”). The amendments in ASU 2020-08 clarify when an entity should assess whether a callable debt security is within the scope of accounting guidance, which impacts the amortization period for nonrefundable fees and other costs. ASU 2020-08 became effective for interim and annual reporting periods beginning after December 15, 2020. The amendments are to be applied on a prospective basis as of the beginning of the period of adoption for existing or newly purchased callable debt securities. We adopted ASU 2020-08 on January 1, 2021, and the adoption did not have an impact on our consolidated financial position, results of operations or cash flows. In December 2019, the FASB issued Accounting Standards Update No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (“ASU 2019-12”). The amendments in ASU 2019-12 remove certain exceptions to the general principles in Accounting Standards Codification Topic 740. The amendments also clarify and amend existing guidance to improve consistent application. The amendments became effective for our annual reporting periods beginning after December 15, 2020. The transition method (retrospective, modified retrospective, or prospective basis) related to the amendments depends on the applicable guidance, and all amendments for which there is no transition guidance specified are to be applied on a prospective basis. We adopted ASU 2019-12 on January 1, 2021, and the adoption did not have an impact on our consolidated financial position, results of operations or cash flows. Recent Accounting Guidance Not Yet Adopted: In November 2020, the FASB issued Accounting Standards Update No. 2020-11, Financial Services—Insurance (Topic 944): Effective Date and Early Application (“ASU 2020-11”). The amendments in ASU 2020-11 make changes to the effective date and early application of Accounting Standards Update No. 2018-12, Financial Services—Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (“ASU 2018-12”), which was issued in November 2018. The amendments in ASU 2020-11 have extended the original effective date by one year, and now the amendments are required for our interim and annual reporting periods beginning after December 15, 2022. The amendments in ASU 2018-12 make changes to a variety of areas to simplify or improve the existing recognition, measurement, presentation and disclosure requirements for long-duration contracts issued by an insurance entity. The amendments require insurers to annually review the assumptions they make about their policyholders and update the liabilities for future policy benefits if the assumptions change. The amendments also simplify the amortization of deferred contract acquisition costs and add new disclosure requirements about the assumptions insurers use to measure their liabilities and how they may affect future cash flows. The amendments related to the liability for future policy benefits for traditional and limited-payment contracts and deferred acquisition costs are to be applied to contracts in force as of the beginning of the earliest period presented, with an option to apply such amendments retrospectively with a cumulative-effect adjustment to the opening balance of retained earnings as of the earliest period presented. The amendments for market risk benefits are to be applied retrospectively. We are currently evaluating the effects the adoption of ASU 2020-11 and ASU 2018-12 will have on our consolidated financial position, results of operations, cash flows, and related disclosures. In August 2020, the FASB issued Accounting Standards Update No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity (“ASU 2020-06”) . The amendments eliminate two of the three accounting models that require separate accounting for convertible features of debt securities, simplify the contract settlement assessment for equity classification, require the use of the if-converted method for all convertible instruments in the diluted earnings per share calculation and expand disclosure requirements. The amendments are effective for our annual and interim reporting periods beginning after December 15, 2021, with early adoption permitted for reporting periods beginning after December 15, 2020. The guidance can be applied on a full retrospective basis to all periods presented or a modified retrospective basis with a cumulative effect adjustment to the opening balance of retained earnings during the period of adoption. We are currently evaluating the effects the adoption of ASU 2020-06 will have on our consolidated financial statements and disclosures.

Business Optimization Initiat_2

Business Optimization Initiatives (Tables)	6 Months Ended
	Jun. 30, 2021
Business Optimization Initiatives [Abstract]
Business Optimization Initiatives	A summary of the activity related to the liability for the employee termination costs during the six months ended June 30, 2021, by reportable segment, is as follows: Commercial & Specialty Business Government Business IngenioRx Other Total 2020 Business Optimization Initiatives Employee termination costs: Liability for employee termination costs at January 1, 2021 $ 92 $ 88 $ 1 $ 6 $ 187 Payments (12) (13) — (1) (26) Liability for employee termination costs at June 30, 2021 $ 80 $ 75 $ 1 $ 5 $ 161

Investments (Tables)

Investments (Tables)	6 Months Ended
	Jun. 30, 2021
Investments [Abstract]
Current and Long-Term Investments, Available-For-Sale	A summary of current and long-term fixed maturity securities, available-for-sale, at June 30, 2021 and December 31, 2020 is as follows: Cost or Non-Credit Gross Gross Unrealized Losses Allowance Estimated Less than 12 Months June 30, 2021 Fixed maturity securities: United States Government securities $ 1,322 $ 10 $ (12) $ — $ — $ 1,320 $ — Government sponsored securities 60 5 — — — 65 — Foreign government securities 344 10 (3) (1) — 350 — States, municipalities and political subdivisions 5,126 360 (2) (1) — 5,483 — Corporate securities 11,661 558 (31) (8) (4) 12,176 — Residential mortgage-backed securities 4,337 117 (12) (8) (2) 4,432 — Commercial mortgage-backed securities 73 3 — (3) — 73 — Other securities 2,506 32 (2) (6) — 2,530 — Total fixed maturity securities $ 25,429 $ 1,095 $ (62) $ (27) $ (6) $ 26,429 $ — December 31, 2020 Fixed maturity securities: United States Government securities $ 765 $ 11 $ (2) $ — $ — $ 774 $ — Government sponsored securities 63 6 — — — 69 — Foreign government securities 290 17 (2) — — 305 — States, municipalities and political subdivisions 5,185 395 (1) — — 5,579 — Corporate securities 10,233 697 (20) (11) (7) 10,892 (1) Residential mortgage-backed securities 4,208 154 (8) (9) — 4,345 (2) Commercial mortgage-backed securities 73 3 (1) (3) — 72 — Other securities 1,937 33 (5) (6) — 1,959 — Total fixed maturity securities $ 22,754 $ 1,316 $ (39) $ (29) $ (7) $ 23,995 $ (3)
Aggregate Fair Value and Gross Unrealized Loss of Fixed Maturity Securities in an Unrealized Loss Position	For fixed maturity securities in an unrealized loss position at June 30, 2021 and December 31, 2020, the following table summarizes the aggregate fair values and gross unrealized losses by length of time those securities have continuously been in an unrealized loss position: Less than 12 Months 12 Months or Greater (Securities are whole amounts) Number of Estimated Gross Number of Estimated Gross June 30, 2021 Fixed maturity securities: United States Government securities 62 $ 766 $ (12) 1 $ 8 $ — Government sponsored securities 1 1 — — — — Foreign government securities 153 114 (3) 22 11 (1) States, municipalities and political subdivisions 132 231 (2) 4 11 (1) Corporate securities 1,158 1,718 (31) 179 204 (8) Residential mortgage-backed securities 385 1,372 (12) 108 147 (8) Commercial mortgage-backed securities — — — 4 8 (3) Other securities 228 665 (2) 58 112 (6) Total fixed maturity securities 2,119 $ 4,867 $ (62) 376 $ 501 $ (27) December 31, 2020 Fixed maturity securities: United States Government securities 27 $ 301 $ (2) — $ — $ — Government sponsored securities — — — 1 — — Foreign government securities 55 35 (2) 9 4 — States, municipalities and political subdivisions 36 57 (1) 1 3 — Corporate securities 646 765 (20) 150 169 (11) Residential mortgage-backed securities 224 442 (8) 90 110 (9) Commercial mortgage-backed securities 6 16 (1) 3 4 (3) Other securities 207 509 (5) 79 179 (6) Total fixed maturity securities 1,201 $ 2,125 $ (39) 333 $ 469 $ (29)
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss	The table below presents a roll-forward by major security type of the allowance for credit losses on fixed maturity securities available-for-sale held at period end for the three and six months ended June 30, 2021 and 2020: Three Months Ended June 30, 2021 Six Months Ended June 30, 2021 Corporate Securities Residential mortgage-backed securities Total Corporate Securities Residential mortgage-backed securities Total Allowance for credit losses: Beginning balance $ 6 $ 2 $ 8 $ 7 $ — $ 7 Additions for securities for which no previous expected credit losses were recognized — — — 1 — 1 Securities sold during the period (2) — (2) (2) — (2) (Decreases) increases to the allowance for credit losses on securities — — — (2) 2 — Total allowance for credit losses, ending balance $ 4 $ 2 $ 6 $ 4 $ 2 $ 6 Three Months Ended June 30, 2020 Six Months Ended June 30, 2020 Corporate Securities Foreign Government Securities Total Corporate Securities Foreign Government Securities Total Allowance for credit losses: Beginning balance $ 51 $ — $ 51 $ — $ — $ — Additions for securities for which no previous expected credit losses were recognized 9 1 10 60 1 61 Securities sold during the period (8) — (8) (8) — (8) Decreases to the allowance for credit losses on securities (29) — (29) (29) — (29) Total allowance for credit losses, ending balance $ 23 $ 1 $ 24 $ 23 $ 1 $ 24
Amortized Cost and Fair Value of Fixed Maturity Securities, By Contractual Maturity	The amortized cost and fair value of fixed maturity securities at June 30, 2021, by contractual maturity, are shown below. Expected maturities may differ from contractual maturities because the issuers of the securities may have the right to prepay obligations. Amortized Estimated Due in one year or less $ 745 $ 749 Due after one year through five years 6,392 6,644 Due after five years through ten years 8,370 8,673 Due after ten years 5,512 5,858 Mortgage-backed securities 4,410 4,505 Total fixed maturity securities $ 25,429 $ 26,429
Proceeds and Realized Gains and Losses from Fixed Maturity Securities	Proceeds from sales, maturities, calls or redemptions of fixed maturity securities during the three and six months ended June 30, 2021 and 2020 are as follows: Three Months Ended June 30 Six Months Ended June 30 2021 2020 2021 2020 Proceeds $ 627 $ 2,618 $ 5,950 $ 4,549
Investments In Equity Securities	A summary of marketable equity securities at June 30, 2021 and December 31, 2020 is as follows: June 30, 2021 December 31, 2020 Equity securities: Exchange traded funds $ 1,596 $ 1,154 Fixed maturity mutual funds — 144 Common equity securities 73 201 Private equity securities 77 60 Total $ 1,746 $ 1,559
Net Realized Gains and Losses on Investments	Net realized investment gains (losses) on investments for the three and six months ended June 30, 2021 and 2020 are as follows: Three Months Ended June 30 Six Months Ended June 30 2021 2020 2021 2020 Net realized gains (losses): Fixed maturity securities: Gross realized gains from sales $ 47 $ 37 $ 103 $ 80 Gross realized losses from sales (12) (50) (24) (70) Impairment recoveries (losses) recognized in income 2 27 1 (24) Net realized gains (losses) from sales of fixed maturity securities 37 14 80 (14) Equity securities: Gross realized gains 23 64 28 65 Gross realized losses (5) (19) (76) (70) Net realized gains (losses) on equity securities 18 45 (48) (5) Other invested assets: Gross realized gains 90 — 95 6 Impairment recoveries (losses) recognized in income 2 (29) (6) (35) Net realized gains (losses) from sales of other investments 92 (29) 89 (29) Net realized gains (losses) on investments $ 147 $ 30 $ 121 $ (48)
Gains (Losses) Related to Equity Securities	The gains and losses related to equity securities for the three and six months ended June 30, 2021 and 2020 are as follows: Three Months Ended June 30 Six Months Ended June 30 2021 2020 2021 2020 Net realized gains (losses) recognized on equity securities $ 18 $ 45 $ (48) $ (5) Less: Net realized gains (losses) recognized on equity securities sold during the period 1 20 (56) 5 Unrealized gains (losses) recognized on equity securities still held at the end of the period $ 17 $ 25 $ 8 $ (10)
Securities Lending Programs	The remaining contractual maturity of our securities lending agreements at June 30, 2021 is as follows: Overnight and Continuous Securities lending collateral Cash $ 1,739 United States Government securities 102 Total $ 1,841

Fair Value (Tables)

Fair Value (Tables)	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements By Level For Assets Measured At Fair Value On A Recurring Basis	A summary of fair value measurements by level for assets and liabilities measured at fair value on a recurring basis at June 30, 2021 and December 31, 2020 is as follows: Level I Level II Level III Total June 30, 2021 Assets: Cash equivalents $ 2,044 $ — $ — $ 2,044 Fixed maturity securities, available-for-sale: United States Government securities — 1,320 — 1,320 Government sponsored securities — 65 — 65 Foreign government securities — 350 — 350 States, municipalities and political subdivisions, tax-exempt — 5,483 — 5,483 Corporate securities — 11,825 351 12,176 Residential mortgage-backed securities — 4,430 2 4,432 Commercial mortgage-backed securities — 73 — 73 Other securities — 2,523 7 2,530 Total fixed maturity securities, available-for-sale — 26,069 360 26,429 Equity securities: Exchange traded funds 1,596 — — 1,596 Common equity securities 6 67 — 73 Private equity securities — — 77 77 Total equity securities 1,602 67 77 1,746 Other invested assets - common equity securities 184 — — 184 Securities lending collateral — 1,841 — 1,841 Derivatives — 91 — 91 Total assets $ 3,830 $ 28,068 $ 437 $ 32,335 Liabilities: Derivatives $ — $ (31) $ — $ (31) Total liabilities $ — $ (31) $ — $ (31) December 31, 2020 Assets: Cash equivalents $ 3,163 $ — $ — $ 3,163 Fixed maturity securities, available-for-sale: United States Government securities — 774 — 774 Government sponsored securities — 69 — 69 Foreign government securities — 305 — 305 States, municipalities and political subdivisions, tax-exempt — 5,579 — 5,579 Corporate securities — 10,567 325 10,892 Residential mortgage-backed securities — 4,343 2 4,345 Commercial mortgage-backed securities — 72 — 72 Other securities — 1,954 5 1,959 Total fixed maturity securities, available-for-sale — 23,663 332 23,995 Equity securities: Exchange traded funds 1,154 — — 1,154 Fixed maturity mutual funds — 144 — 144 Common equity securities 171 30 — 201 Private equity securities — — 60 60 Total equity securities 1,325 174 60 1,559 Securities lending collateral — 1,199 — 1,199 Derivatives — 43 — 43 Total assets $ 4,488 $ 25,079 $ 392 $ 29,959 Liabilities: Derivatives $ — $ (5) $ — $ (5) Total liabilities $ — $ (5) $ — $ (5)
Reconciliation Of The Beginning And Ending Balances Of Assets Measured At Fair Value On A Recurring Basis Using Level III Inputs	A reconciliation of the beginning and ending balances of assets measured at fair value on a recurring basis using Level III inputs for the three months ended June 30, 2021 and 2020 is as follows: Corporate Residential Other Equity Total Three Months Ended June 30, 2021 Beginning balance at April 1, 2021 $ 324 $ 2 $ 5 $ 65 $ 396 Total gains: Recognized in net income — — — 5 5 Recognized in accumulated other comprehensive (loss) income 3 — — — 3 Purchases 65 — 2 8 75 Sales (9) — — (1) (10) Settlements (32) — — — (32) Ending balance at June 30, 2021 $ 351 $ 2 $ 7 $ 77 $ 437 Change in unrealized losses included in net income related to assets still held at June 30, 2021 $ — $ — $ — $ 5 $ 5 Three Months Ended June 30, 2020 Beginning balance at April 1, 2020 $ 316 $ 2 $ 5 $ 82 $ 405 Total gains (losses): Recognized in net income 1 — — (10) (9) Recognized in accumulated other comprehensive (loss) income (7) — — — (7) Purchases 14 — — 3 17 Sales (1) — — (13) (14) Settlements (9) — — — (9) Ending balance at June 30, 2020 $ 314 $ 2 $ 5 $ 62 $ 383 Change in unrealized losses included in net income related to assets still held at June 30, 2020 $ — $ — $ — $ (10) $ (10) A reconciliation of the beginning and ending balances of assets measured at fair value on a recurring basis using Level III inputs for the six months ended June 30, 2021 and 2020 is as follows: Corporate Residential Other Equity Total Six Months Ended June 30, 2021 Beginning balance at January 1, 2021 $ 325 $ 2 $ 5 $ 60 $ 392 Total gains: Recognized in net income — — — 13 13 Recognized in accumulated other comprehensive (loss) income 6 — — — 6 Purchases 104 — 2 8 114 Sales (11) — — (4) (15) Settlements (73) — — — (73) Ending balance at June 30, 2021 $ 351 $ 2 $ 7 $ 77 $ 437 Change in unrealized losses included in net income related to assets still held at June 30, 2021 $ — $ — $ — $ 13 $ 13 Six Months Ended June 30, 2020 Beginning balance at January 1, 2020 $ 303 $ 2 $ 7 $ 85 $ 397 Total losses: Recognized in net income (1) — — (16) (17) Recognized in accumulated other comprehensive (loss) income (17) — — — (17) Purchases 39 — — 15 54 Sales (4) — — (22) (26) Settlements (19) — (2) — (21) Transfers into Level III 13 — — — 13 Ending balance at June 30, 2020 $ 314 $ 2 $ 5 $ 62 $ 383 Change in unrealized losses included in net income related to assets still held at June 30, 2020 $ — $ — $ — $ (17) $ (17)
Carrying And Fair Values By Level Of Financial Instruments Not Recorded At Fair Value On Consolidated Balance Sheet	A summary of the estimated fair values by level of each class of financial instrument that is recorded at its carrying value on our consolidated balance sheets at June 30, 2021 and December 31, 2020 is as follows: Carrying Estimated Fair Value Level I Level II Level III Total June 30, 2021 Assets: Other invested assets $ 4,733 $ — $ — $ 4,733 $ 4,733 Liabilities: Debt: Short-term borrowings 175 — 175 — 175 Commercial paper 550 — 550 — 550 Notes 22,439 — 25,425 — 25,425 Convertible debentures 77 — 610 — 610 December 31, 2020 Assets: Other invested assets $ 4,285 $ — $ — $ 4,285 $ 4,285 Liabilities: Debt: Commercial paper 250 — 250 — 250 Notes 19,677 — 23,307 — 23,307 Convertible debentures 108 — 712 — 712

Medical Claims Payable (Tables)

Medical Claims Payable (Tables)	6 Months Ended
	Jun. 30, 2021
Liability for Claims and Claims Adjustment Expense [Abstract]
Reconciliation Of The Beginning And Ending Balances For Medical Claims Payable	A reconciliation of the beginning and ending balances for medical claims payable, by segment (see Note 15, “Segment Information”), for the six months ended June 30, 2021 is as follows: Commercial Government Other Total Gross medical claims payable, beginning of period $ 3,294 $ 7,646 $ 195 $ 11,135 Ceded medical claims payable, beginning of period (13) (33) — (46) Net medical claims payable, beginning of period 3,281 7,613 195 11,089 Business combinations and purchase adjustments — 375 45 420 Net incurred medical claims: Current period 13,360 34,232 751 48,343 Prior periods redundancies (570) (1,190) (12) (1,772) Total net incurred medical claims 12,790 33,042 739 46,571 Net payments attributable to: Current period medical claims 10,295 26,647 591 37,533 Prior periods medical claims 2,154 5,455 158 7,767 Total net payments 12,449 32,102 749 45,300 Net medical claims payable, end of period 3,622 8,928 230 12,780 Ceded medical claims payable, end of period 11 30 — 41 Gross medical claims payable, end of period $ 3,633 $ 8,958 $ 230 $ 12,821 At June 30, 2021, the total of net incurred but not reported liabilities plus expected development on reported claims for the Commercial & Specialty Business was $71, $486 and $3,065 for the claim years 2019 and prior, 2020 and 2021, respectively. At June 30, 2021, the total of net incurred but not reported liabilities plus expected development on reported claims for the Government Business was $105, $862 and $7,961 for the claim years 2019 and prior, 2020 and 2021, respectively. At June 30, 2021, the total of net incurred but not reported liabilities plus expected development on reported claims for Other was $0, $25 and $205 for the claim years 2019 and prior, 2020 and 2021, respectively. A reconciliation of the beginning and ending balances for medical claims payable, by segment (see Note 15, “Segment Information”), for the six months ended June 30, 2020 is as follows: Commercial Government Other Total Gross medical claims payable, beginning of period $ 3,039 $ 5,608 $ — $ 8,647 Ceded medical claims payable, beginning of period (14) (19) — (33) Net medical claims payable, beginning of period 3,025 5,589 — 8,614 Business combinations and purchase adjustments — 141 198 339 Net incurred medical claims: Current period 11,318 28,162 498 39,978 Prior periods redundancies (374) (326) — (700) Total net incurred medical claims 10,944 27,836 498 39,278 Net payments attributable to: Current period medical claims 9,014 22,115 496 31,625 Prior periods medical claims 2,218 4,823 — 7,041 Total net payments 11,232 26,938 496 38,666 Net medical claims payable, end of period 2,737 6,628 200 9,565 Ceded medical claims payable, end of period 62 28 — 90 Gross medical claims payable, end of period $ 2,799 $ 6,656 $ 200 $ 9,655 The favorable development recognized in the six months ended June 30, 2021 and 2020 resulted primarily from trend factors in late 2020 and late 2019, respectively, developing more favorably than originally expected. Favorable development in the completion factors resulting from the latter parts of 2020 and 2019, respectively, developing faster than expected also contributed to the favorability. The impact from COVID-19 on healthcare utilization and medical claims submission patterns continues to provide increased estimation uncertainty on our incurred but not reported liability at June 30, 2021.
Reconciliation of Net Incurred Medical Claims to Benefit Expense	The reconciliation of net incurred medical claims to benefit expense included in our consolidated statements of income for periods in 2021 is as follows: Three Months Ended Six Months Ended March 31, 2021 June 30, 2021 Net incurred medical claims: Commercial & Specialty Business $ 6,072 $ 6,718 $ 12,790 Government Business 16,319 16,723 33,042 Other 336 403 739 Total net incurred medical claims 22,727 23,844 46,571 Quality improvement and other claims expense 972 919 1,891 Benefit expense $ 23,699 $ 24,763 $ 48,462 The reconciliation of net incurred medical claims to benefit expense included in our consolidated statements of income for periods in 2020 is as follows: Three Months Ended Six Months Ended March 31, 2020 June 30, 2020 Net incurred medical claims: Commercial & Specialty Business $ 5,797 $ 5,147 $ 10,944 Government Business 14,603 13,233 27,836 Other 130 368 498 Total net incurred medical claims 20,530 18,748 39,278 Quality improvement and other claims expense 959 799 1,758 Benefit expense $ 21,489 $ 19,547 $ 41,036
Reconciliation of Short Duration Medical Claims Payable to the Consolidated Medical Claims Payable	The reconciliation of the medical claims payable reflected in the tables above to the consolidated ending balance for medical claims payable included in the consolidated balance sheet, as of June 30, 2021, is as follows: Commercial Government Other Total Net medical claims payable, end of period $ 3,622 $ 8,928 $ 230 $ 12,780 Ceded medical claims payable, end of period 11 30 — 41 Insurance lines other than short duration — 255 — 255 Gross medical claims payable, end of period $ 3,633 $ 9,213 $ 230 $ 13,076

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2021
Debt Disclosure [Abstract]
Convertible Debenture Terms	The following table summarizes at June 30, 2021 the related balances, conversion rate and conversion price of the Debentures: Outstanding principal amount $ 113 Unamortized debt discount $ 35 Net debt carrying amount $ 78 Equity component carrying amount $ 41 Conversion rate (shares of common stock per $1,000 of principal amount) 14.1462 Effective conversion price (per $1,000 of principal amount) $ 70.6904

Capital Stock (Tables)

Capital Stock (Tables)	6 Months Ended
	Jun. 30, 2021
Banking Regulation, Total Capital [Abstract]
Summary of Cash Dividend Activity	A summary of our cash dividend activity for the six months ended June 30, 2021 and 2020 is as follows: Declaration Date Record Date Payment Date Cash Dividend per Share Total Six Months Ended June 30, 2021 January 26, 2021 March 10, 2021 March 25, 2021 $1.13 $ 277 April 20, 2021 June 10, 2021 June 25, 2021 $1.13 $ 278 Six Months Ended June 30, 2020 January 28, 2020 March 16, 2020 March 27, 2020 $0.95 $ 240 April 28, 2020 June 10, 2020 June 25, 2020 $0.95 $ 242
Summary of Share Repurchases	A summary of common stock repurchases for the six months ended June 30, 2021 and 2020 is as follows: Six Months Ended June 30 2021 2020 Shares repurchased 2.7 2.1 Average price per share $ 346.47 $ 273.72 Aggregate cost $ 927 $ 584 Authorization remaining at the end of the period $ 5,165 $ 3,208
Summary of Stock Option Activity	A summary of stock option activity for the six months ended June 30, 2021 is as follows: Number of Weighted- Weighted- Aggregate Outstanding at January 1, 2021 3.1 $ 230.00 Granted 0.7 312.33 Exercised (0.6) 193.55 Forfeited or expired (0.1) 286.70 Outstanding at June 30, 2021 3.1 253.91 7.23 $ 402 Exercisable at June 30, 2021 1.6 215.56 5.94 $ 270
Summary of Nonvested Restricted Stock Activity Including Restricted Stock Units	A summary of the nonvested restricted stock activity, including restricted stock units, for the six months ended June 30, 2021 is as follows: Restricted Weighted- Nonvested at January 1, 2021 1.3 $ 272.51 Granted 0.9 312.50 Vested (0.8) 244.24 Forfeited (0.1) 287.67 Nonvested at June 30, 2021 1.3 295.57
Summary of Weighted-Average Assumptions Used to Estimate the Fair Value of Options Granted During the Periods	The following weighted-average assumptions were used to estimate the fair values of options granted during the six months ended June 30, 2021 and 2020: Six Months Ended June 30 2021 2020 Risk-free interest rate 1.44 % 1.30 % Volatility factor 30.00 % 26.00 % Quarterly dividend yield 0.360 % 0.350 % Weighted-average expected life (years) 5.50 4.30
Schedule of Weighted-Average Fair Values Determined for the Periods	The following weighted-average fair values per option or share were determined for the six months ended June 30, 2021 and 2020: Six Months Ended June 30 2021 2020 Options granted during the period $ 79.22 $ 54.04 Restricted stock awards granted during the period 312.50 272.14

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Tables)	6 Months Ended
	Jun. 30, 2021
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Components Of Accumulated Other Comprehensive Loss	A reconciliation of the components of accumulated other comprehensive loss at June 30, 2021 and 2020 is as follows: June 30 2021 2020 Investments: Gross unrealized gains $ 1,095 $ 974 Gross unrealized losses (89) (229) Net pre-tax unrealized gains 1,006 745 Deferred tax liability (240) (183) Adjustment for noncontrolling interest (4) — Net unrealized gains on investments 762 562 Non-credit components of impairments on investments: Gross unrealized losses — (32) Deferred tax asset — 8 Net unrealized non-credit component of impairments on investments — (24) Cash flow hedges: Gross unrealized losses (308) (323) Deferred tax asset 64 67 Net unrealized losses on cash flow hedges (244) (256) Defined benefit pension plans: Deferred net actuarial loss (723) (707) Deferred prior service credits — (1) Deferred tax asset 184 181 Net unrecognized periodic benefit costs for defined benefit pension plans (539) (527) Postretirement benefit plans: Deferred net actuarial loss (3) (25) Deferred prior service costs 10 16 Deferred tax (liability) asset (2) 2 Net unrecognized periodic benefit credit (costs) for postretirement benefit plans 5 (7) Foreign currency translation adjustments: Gross unrealized losses (1) (3) Deferred tax asset — 1 Net unrealized losses on foreign currency translation adjustments (1) (2) Accumulated other comprehensive loss $ (17) $ (254)
Other Comprehensive Income (Loss) Reclassification Adjustments	Other comprehensive income (loss) reclassification adjustments for the three months ended June 30, 2021 and 2020 are as follows: Three Months Ended June 30 2021 2020 Investments: Net holding gains on investment securities arising during the period, net of tax expense of ($61) and ($238), respectively $ 201 $ 741 Reclassification adjustment for net realized gains on investment securities, net of tax expense of $7 and $4, respectively (26) (11) Total reclassification adjustment on investments 175 730 Non-credit component of impairments on investments: Non-credit component of impairments on investments, net of tax expense of $0 and ($2), respectively 1 10 Cash flow hedges: Holding gain, net of tax expense of ($1) and ($1), respectively 2 3 Other: Net change in unrecognized periodic benefit costs for defined benefit pension and postretirement benefit plans, net of tax expense of ($2) and ($4), respectively 8 10 Foreign currency translation adjustment, net of tax benefit of $1 and $0, respectively (6) 1 Net gain recognized in other shareholders’ comprehensive income, net of tax expense of ($56) and ($241), respectively 180 754 Net loss related to noncontrolling interests, net of tax benefit of $1 and $0, respectively (2) — Net gain recognized in other comprehensive income, net of tax expense of ($55) and ($241), respectively $ 178 $ 754 Other comprehensive income (loss) reclassification adjustments for the six months ended June 30, 2021 and 2020 are as follows: Six Months Ended June 30 2021 2020 Investments: Net holding (loss) gains on investment securities arising during the period, net of tax benefit (expense) of $46 and ($23), respectively $ (125) $ 33 Reclassification adjustment for net realized (loss) gains on investment securities, net of tax expense (benefit) of $16 and ($5), respectively (62) 8 Total reclassification adjustment on investments (187) 41 Non-credit component of impairments on investments: Non-credit component of impairments on investments, net of tax (expense) benefit of ($1) and $7, respectively 2 (22) Cash flow hedges: Holding gain, net of tax expense of ($2) and ($2), respectively 6 6 Other: Net change in unrecognized periodic benefit costs for defined benefit pension and postretirement benefit plans, net of tax expense of ($6) and ($7), respectively 18 17 Foreign currency translation adjustment, net of tax benefit of $1 and $0, respectively (6) — Net (loss) gain recognized in other shareholders’ comprehensive income, net of tax benefit (expense) of $54 and ($30), respectively (167) 42 Net loss related to noncontrolling interests, net of tax benefit of $1 and $0, respectively — — Net (loss) gain recognized in other comprehensive income, net of tax benefit (expense) of $55 and ($30), respectively $ (167) $ 42

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2021
Earnings Per Share [Abstract]
Denominator for Basic and Diluted Earnings Per Share	The denominator for basic and diluted earnings per share for the three and six months ended June 30, 2021 and 2020 is as follows: Three Months Ended Six Months Ended 2021 2020 2021 2020 Denominator for basic earnings per share – weighted-average shares 244.5 252.2 244.8 252.3 Effect of dilutive securities – employee stock options, nonvested restricted stock awards and convertible debentures 2.9 3.2 3.0 3.6 Denominator for diluted earnings per share 247.4 255.4 247.8 255.9

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Jun. 30, 2021
Segment Reporting [Abstract]
Financial Data By Reportable Segment	Financial data by reportable segment for the three and six months ended June 30, 2021 and 2020 is as follows: Commercial Government IngenioRx Other Eliminations Total Three Months Ended June 30, 2021 Operating revenue - unaffiliated $ 9,550 $ 20,066 $ 3,042 $ 621 $ — $ 33,279 Operating revenue - affiliated — — 3,177 1,896 (5,073) — Operating gain 791 868 405 17 — 2,081 Three Months Ended June 30, 2020 Operating revenue - unaffiliated $ 8,789 $ 17,242 $ 2,544 $ 603 $ — $ 29,178 Operating revenue - affiliated — — 2,725 849 (3,574) — Operating gain 1,372 1,618 304 66 — 3,360 Six Months Ended June 30, 2021 Operating revenue - unaffiliated $ 19,041 $ 39,349 $ 5,780 $ 1,207 $ — $ 65,377 Operating revenue - affiliated — — 6,301 3,680 (9,981) — Operating gain 2,059 1,346 812 25 — 4,242 Six Months Ended June 30, 2020 Operating revenue - unaffiliated $ 18,150 $ 34,708 $ 4,887 $ 881 $ — $ 58,626 Operating revenue - affiliated — — 5,579 1,598 (7,177) — Operating gain 2,792 2,029 653 80 — 5,554
Major Product Revenue by Segment	The major product revenues for each of the reportable segments for the three and six months ended June 30, 2021 and 2020 are as follows: Three Months Ended Six Months Ended 2021 2020 2021 2020 Commercial & Specialty Business Managed care products $ 7,772 $ 7,132 $ 15,461 $ 14,700 Managed care services 1,416 1,263 2,802 2,645 Dental/Vision products and services 335 284 671 599 Other 27 110 107 206 Total Commercial & Specialty Business 9,550 8,789 19,041 18,150 Government Business Managed care products 19,965 17,149 39,147 34,524 Managed care services 101 93 202 184 Total Government Business 20,066 17,242 39,349 34,708 IngenioRx Pharmacy products and services 6,219 5,269 12,081 10,466 Total IngenioRx 6,219 5,269 12,081 10,466 Other Integrated health services 2,366 1,376 4,615 2,325 Other 151 76 272 154 Total Other Business 2,517 1,452 4,887 2,479 Eliminations Eliminations (5,073) (3,574) (9,981) (7,177) Total product revenues $ 33,279 $ 29,178 $ 65,377 $ 58,626
Reconciliation Of Reportable Segments Operating Revenues To Total Revenues Reported In The Consolidated Statements Of Income	A reconciliation of reportable segments’ operating revenue to the amounts of total revenues included in our consolidated statements of income for the three and six months ended June 30, 2021 and 2020 is as follows: Three Months Ended Six Months Ended 2021 2020 2021 2020 Reportable segments’ operating revenue $ 33,279 $ 29,178 $ 65,377 $ 58,626 Net investment income 400 57 691 311 Net realized gains (losses) on financial instruments 172 29 168 (52) Total revenues $ 33,851 $ 29,264 $ 66,236 $ 58,885
Reconciliation Of Reportable Segments Operating Gain To Income Before Income Tax Expense Included In The Consolidated Statements Of Income	A reconciliation of reportable segments’ operating gain to income before income tax expense included in our consolidated statements of income for the three and six months ended June 30, 2021 and 2020 is as follows: Three Months Ended Six Months Ended 2021 2020 2021 2020 Reportable segments’ operating gain $ 2,081 $ 3,360 $ 4,242 $ 5,554 Net investment income 400 57 691 311 Net realized gains (losses) on financial instruments 172 29 168 (52) Interest expense (205) (201) (397) (395) Amortization of other intangible assets (90) (93) (170) (176) Loss on extinguishment of debt (5) (3) (5) (4) Income before income tax expense $ 2,353 $ 3,149 $ 4,529 $ 5,238

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2021
Leases [Abstract]
Lessee, Operating Lease, Disclosure [Table Text Block]	The information related to our leases is as follows: Balance Sheet Location June 30, 2021 December 31, 2020 Operating Leases Right-of-use assets Other noncurrent assets $ 683 $ 646 Lease liabilities, current Other current liabilities 144 110 Lease liabilities, noncurrent Other noncurrent liabilities 833 847 Three Months Ended Six Months Ended 2021 2020 2021 2020 Lease Expense Operating lease expense $ 34 $ 59 $ 63 $ 106 Short-term lease expense 12 14 24 27 Sublease income (1) (4) (2) (7) Total lease expense $ 45 $ 69 $ 85 $ 126 Other information Operating cash paid for amounts included in the measurement of lease liabilities, operating leases $ 36 $ 46 $ 88 $ 90 Right-of-use assets obtained in exchange for new lease liabilities, operating leases $ 145 $ 33 $ 160 $ 356
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	Future lease payments for noncancellable operating leases with initial or remaining terms of one year or more are as follows: 2021 (excluding the six months ended June 30, 2021) $ 105 2022 198 2023 175 2024 146 2025 105 Thereafter 324 Total future minimum payments 1,053 Less imputed interest (76) Total lease liabilities $ 977

Organization (Details)

Organization (Details) medical_member in Millions	Jun. 30, 2021medical_membercountystates
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of Medical Members | medical_member	44
Number of counties in the Kansas City area the Company does not serve | county	30
Number of states in which the Company is licensed to conduct insurance operations | states	50

Basis of Presentation and Signf

Basis of Presentation and Signficant Accounting Policies Basis of Presentation and Significant Acconting Policies (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Accounting Policies [Abstract]
Customer funds and cash and cash equivalents on deposit for regulatory requirements	$ 248	$ 170
Securities lending transactions, initial collateral percentage value	102.00%
Premium receivable, allowance for doubtful accounts	$ 152	146
Self-funded receivables, allowance for doubtful accounts	91	54
Allowance for doubtful accounts, Other Receivables, current	$ 479	$ 374

Business Acquisitions Business

Business Acquisitions Business Acquisition (Assets Liabilities Acquired) (Details) individuals in Millions, $ in Millions	6 Months Ended
	Jun. 30, 2021USD ($)states	Apr. 28, 2021states	Dec. 31, 2020USD ($)	Feb. 28, 2020individualsstates
Business Acquisition [Line Items]
Number of States in which Company Operates | states	50
Goodwill	$ 24,399		$ 21,691
myNEXUS [Member]
Business Acquisition [Line Items]
Number of States in which Company Operates | states		20
myNEXUS [Member] | Other Segment [Member]
Business Acquisition [Line Items]
Goodwill	520
Other intangible assets	284
Beacon Health Options [Member]
Business Acquisition [Line Items]
Number of States in which Company Operates | states				50
Number Of Lives Served | individuals				34
Beacon Health Options [Member] | Other Segment [Member]
Business Acquisition [Line Items]
Goodwill	1,081		$ 1,072
Goodwill, Purchase Accounting Adjustments	9
Other intangible assets	752
MMM Holdings [Member] | Government Business Segment [Member]
Business Acquisition [Line Items]
Goodwill	2,171
Other intangible assets	$ 968
Minimum [Member] | myNEXUS [Member] | Other Segment [Member] | Customer relationships and provider networks
Business Acquisition [Line Items]
Intangible assets amortization period, years	2 years
Minimum [Member] | Beacon Health Options [Member] | Other Segment [Member] | Customer relationships and provider networks
Business Acquisition [Line Items]
Intangible assets amortization period, years	8 years
Maximum [Member] | myNEXUS [Member] | Other Segment [Member] | Customer relationships and provider networks
Business Acquisition [Line Items]
Intangible assets amortization period, years	17 years
Maximum [Member] | Beacon Health Options [Member] | Other Segment [Member] | Customer relationships and provider networks
Business Acquisition [Line Items]
Intangible assets amortization period, years	25 years

Business Optimization Initiat_3

Business Optimization Initiatives (Employee Termination Costs) (Details) - Employee Severance [Member] $ in Millions	6 Months Ended
	Jun. 30, 2021USD ($)
Business Optimization Initiatives [Line Items]
Liability for employee terminations costs, beginning	$ 187
Payments	(26)
Liability for employee terminations costs, ending	161
IngenioRx Segment [Member]
Business Optimization Initiatives [Line Items]
Liability for employee terminations costs, beginning	1
Payments	0
Liability for employee terminations costs, ending	1
Other Segment [Member]
Business Optimization Initiatives [Line Items]
Liability for employee terminations costs, beginning	6
Payments	(1)
Liability for employee terminations costs, ending	5
Government Business Segment [Member]
Business Optimization Initiatives [Line Items]
Liability for employee terminations costs, beginning	88
Payments	(13)
Liability for employee terminations costs, ending	75
Commercial Specialty Business Segment [Member]
Business Optimization Initiatives [Line Items]
Liability for employee terminations costs, beginning	92
Payments	(12)
Liability for employee terminations costs, ending	$ 80

Investments (Current And Long-T

Investments (Current And Long-Term Fixed Maturity Securities, Available-For-Sale) (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019
Investments [Line Items]
Gross Unrealized Gains	$ 1,095			$ 974
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss	6	$ 7	$ 8	24	$ 51	$ 0
Corporate Securities [Member]
Investments [Line Items]
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss	4	7	6	23	51	0
Residential Mortgage-Backed Securities [Member]
Investments [Line Items]
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss	2	0	$ 2	$ 1	$ 0	$ 0
Fixed Maturities [Member]
Investments [Line Items]
Cost or Amortized Cost	25,429	22,754
Gross Unrealized Gains	1,095	1,316
Gross Unrealized Losses, Less than 12 Months	(62)	(39)
Gross Unrealized Losses, 12 Months or Greater	(27)	(29)
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss	(6)	(7)
Available-for-sale Securities	26,429	23,995
Non-Credit Component of Other-Than-Temporary Impairments Recognized in Accumulated Other Comprehensive Loss	0	(3)
Fixed Maturities [Member] | United States Government Securities [Member]
Investments [Line Items]
Cost or Amortized Cost	1,322	765
Gross Unrealized Gains	10	11
Gross Unrealized Losses, Less than 12 Months	(12)	(2)
Gross Unrealized Losses, 12 Months or Greater	0	0
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss	0	0
Available-for-sale Securities	1,320	774
Non-Credit Component of Other-Than-Temporary Impairments Recognized in Accumulated Other Comprehensive Loss	0	0
Fixed Maturities [Member] | Government Sponsored Securities [Member]
Investments [Line Items]
Cost or Amortized Cost	60	63
Gross Unrealized Gains	5	6
Gross Unrealized Losses, Less than 12 Months	0	0
Gross Unrealized Losses, 12 Months or Greater	0	0
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss	0	0
Available-for-sale Securities	65	69
Non-Credit Component of Other-Than-Temporary Impairments Recognized in Accumulated Other Comprehensive Loss	0	0
Fixed Maturities [Member] | Foreign Government Securities [Member]
Investments [Line Items]
Cost or Amortized Cost	344	290
Gross Unrealized Gains	10	17
Gross Unrealized Losses, Less than 12 Months	(3)	(2)
Gross Unrealized Losses, 12 Months or Greater	(1)	0
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss	0	0
Available-for-sale Securities	350	305
Non-Credit Component of Other-Than-Temporary Impairments Recognized in Accumulated Other Comprehensive Loss	0	0
Fixed Maturities [Member] | States, Municipalities And Political Subdivisions [Member]
Investments [Line Items]
Cost or Amortized Cost	5,126	5,185
Gross Unrealized Gains	360	395
Gross Unrealized Losses, Less than 12 Months	(2)	(1)
Gross Unrealized Losses, 12 Months or Greater	(1)	0
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss	0	0
Available-for-sale Securities	5,483	5,579
Non-Credit Component of Other-Than-Temporary Impairments Recognized in Accumulated Other Comprehensive Loss	0	0
Fixed Maturities [Member] | Corporate Securities [Member]
Investments [Line Items]
Cost or Amortized Cost	11,661	10,233
Gross Unrealized Gains	558	697
Gross Unrealized Losses, Less than 12 Months	(31)	(20)
Gross Unrealized Losses, 12 Months or Greater	(8)	(11)
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss	(4)	(7)
Available-for-sale Securities	12,176	10,892
Non-Credit Component of Other-Than-Temporary Impairments Recognized in Accumulated Other Comprehensive Loss	0	(1)
Fixed Maturities [Member] | Residential Mortgage-Backed Securities [Member]
Investments [Line Items]
Cost or Amortized Cost	4,337	4,208
Gross Unrealized Gains	117	154
Gross Unrealized Losses, Less than 12 Months	(12)	(8)
Gross Unrealized Losses, 12 Months or Greater	(8)	(9)
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss	(2)	0
Available-for-sale Securities	4,432	4,345
Non-Credit Component of Other-Than-Temporary Impairments Recognized in Accumulated Other Comprehensive Loss	0	(2)
Fixed Maturities [Member] | Commercial Mortgage-Backed Securities [Member]
Investments [Line Items]
Cost or Amortized Cost	73	73
Gross Unrealized Gains	3	3
Gross Unrealized Losses, Less than 12 Months	0	(1)
Gross Unrealized Losses, 12 Months or Greater	(3)	(3)
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss	0	0
Available-for-sale Securities	73	72
Non-Credit Component of Other-Than-Temporary Impairments Recognized in Accumulated Other Comprehensive Loss	0	0
Fixed Maturities [Member] | Other Securities [Member]
Investments [Line Items]
Cost or Amortized Cost	2,506	1,937
Gross Unrealized Gains	32	33
Gross Unrealized Losses, Less than 12 Months	(2)	(5)
Gross Unrealized Losses, 12 Months or Greater	(6)	(6)
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss	0	0
Available-for-sale Securities	2,530	1,959
Non-Credit Component of Other-Than-Temporary Impairments Recognized in Accumulated Other Comprehensive Loss	$ 0	$ 0

Investments (Aggregate Fair Val

Investments (Aggregate Fair Value And Gross Unrealized Loss Of Fixed Maturity Securities In An Unrealized Loss Position) (Details) - Fixed Maturities [Member] $ in Millions	Jun. 30, 2021USD ($)securities	Dec. 31, 2020USD ($)securities
Schedule of Investments [Line Items]
Number of securities, less than 12 months | securities	2,119	1,201
Estimated fair value, less than 12 months	$ 4,867	$ 2,125
Gross unrealized loss, less than 12 months	$ (62)	$ (39)
Number of securities, 12 months or greater | securities	376	333
Estimated fair value, 12 months or greater	$ 501	$ 469
Gross unrealized loss, 12 months or greater	$ (27)	$ (29)
United States Government Securities [Member]
Schedule of Investments [Line Items]
Number of securities, less than 12 months | securities	62	27
Estimated fair value, less than 12 months	$ 766	$ 301
Gross unrealized loss, less than 12 months	$ (12)	$ (2)
Number of securities, 12 months or greater | securities	1	0
Estimated fair value, 12 months or greater	$ 8	$ 0
Gross unrealized loss, 12 months or greater	$ 0	$ 0
Government Sponsored Securities [Member]
Schedule of Investments [Line Items]
Number of securities, less than 12 months | securities	1	0
Estimated fair value, less than 12 months	$ 1	$ 0
Gross unrealized loss, less than 12 months	$ 0	$ 0
Number of securities, 12 months or greater | securities	0	1
Estimated fair value, 12 months or greater	$ 0	$ 0
Gross unrealized loss, 12 months or greater	$ 0	$ 0
Foreign Government Securities [Member]
Schedule of Investments [Line Items]
Number of securities, less than 12 months | securities	153	55
Estimated fair value, less than 12 months	$ 114	$ 35
Gross unrealized loss, less than 12 months	$ (3)	$ (2)
Number of securities, 12 months or greater | securities	22	9
Estimated fair value, 12 months or greater	$ 11	$ 4
Gross unrealized loss, 12 months or greater	$ (1)	$ 0
States, Municipalities And Political Subdivisions [Member]
Schedule of Investments [Line Items]
Number of securities, less than 12 months | securities	132	36
Estimated fair value, less than 12 months	$ 231	$ 57
Gross unrealized loss, less than 12 months	$ (2)	$ (1)
Number of securities, 12 months or greater | securities	4	1
Estimated fair value, 12 months or greater	$ 11	$ 3
Gross unrealized loss, 12 months or greater	$ (1)	$ 0
Corporate Securities [Member]
Schedule of Investments [Line Items]
Number of securities, less than 12 months | securities	1,158	646
Estimated fair value, less than 12 months	$ 1,718	$ 765
Gross unrealized loss, less than 12 months	$ (31)	$ (20)
Number of securities, 12 months or greater | securities	179	150
Estimated fair value, 12 months or greater	$ 204	$ 169
Gross unrealized loss, 12 months or greater	$ (8)	$ (11)
Residential Mortgage-Backed Securities [Member]
Schedule of Investments [Line Items]
Number of securities, less than 12 months | securities	385	224
Estimated fair value, less than 12 months	$ 1,372	$ 442
Gross unrealized loss, less than 12 months	$ (12)	$ (8)
Number of securities, 12 months or greater | securities	108	90
Estimated fair value, 12 months or greater	$ 147	$ 110
Gross unrealized loss, 12 months or greater	$ (8)	$ (9)
Commercial Mortgage-Backed Securities [Member]
Schedule of Investments [Line Items]
Number of securities, less than 12 months | securities	0	6
Estimated fair value, less than 12 months	$ 0	$ 16
Gross unrealized loss, less than 12 months	$ 0	$ (1)
Number of securities, 12 months or greater | securities	4	3
Estimated fair value, 12 months or greater	$ 8	$ 4
Gross unrealized loss, 12 months or greater	$ (3)	$ (3)
Other Securities [Member]
Schedule of Investments [Line Items]
Number of securities, less than 12 months | securities	228	207
Estimated fair value, less than 12 months	$ 665	$ 509
Gross unrealized loss, less than 12 months	$ (2)	$ (5)
Number of securities, 12 months or greater | securities	58	79
Estimated fair value, 12 months or greater	$ 112	$ 179
Gross unrealized loss, 12 months or greater	$ (6)	$ (6)

Investments (Allowance For Cred

Investments (Allowance For Credit Loss Rollforward) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss, Beginning Balance	$ 8	$ 51	$ 7	$ 0
Additions for securities for which no previous expected credit losses were recognized	0	10	1	61
Allowance for credit loss, securities sold	(2)	(8)	(2)	(8)
Increase (decrease) to the allowance for credit losses on securities	0	(29)	0	(29)
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss, Ending Balance	6	24	6	24
Corporate Securities [Member]
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss, Beginning Balance	6	51	7	0
Additions for securities for which no previous expected credit losses were recognized	0	9	1	60
Allowance for credit loss, securities sold	(2)	(8)	(2)	(8)
Increase (decrease) to the allowance for credit losses on securities	0	(29)	(2)	(29)
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss, Ending Balance	4	23	4	23
Residential Mortgage-Backed Securities [Member]
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss, Beginning Balance	2	0	0	0
Additions for securities for which no previous expected credit losses were recognized	0	1	0	1
Increase (decrease) to the allowance for credit losses on securities	0	0	2	0
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss, Ending Balance	$ 2	$ 1	$ 2	$ 1

Investments (Amortized Cost And

Investments (Amortized Cost And Fair Value Of Fixed Maturity Securities, By Contractual Maturity) (Details) - Fixed Maturities [Member] - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Schedule of Investments [Line Items]
Due in one year or less, Amortized Cost	$ 745
Due after one year through five years, Amortized Cost	6,392
Due after five years through ten years, Amortized Cost	8,370
Due after ten years, Amortized Cost	5,512
Mortgage-backed securities, Amortized Cost	4,410
Available-for-sale securities, Amortized Cost	25,429	$ 22,754
Due in one year or less, Estimated Fair Value	749
Due after one year through five years, Estimated Fair Value	6,644
Due after five years through ten years, Estimated Fair Value	8,673
Due after ten years, Estimated Fair Value	5,858
Mortgage-backed securities, Estimated Fair Value	4,505
Available-for-sale securities, Estimated Fair Value	$ 26,429	$ 23,995

Proceeds (Details)

Proceeds (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Fixed Maturities [Member]
Schedule of Investments [Line Items]
Proceeds from Sale of Available-for-sale Securities	$ 627	$ 2,618	$ 5,950	$ 4,549

Investments (Current Equity Sec

Investments (Current Equity Securities) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Marketable Securities [Line Items]
Equity Securities	$ 1,746	$ 1,559
Exchange Traded Funds [Member]
Marketable Securities [Line Items]
Equity Securities	1,596	1,154
Fixed Maturity Mutual Funds [Member]
Marketable Securities [Line Items]
Equity Securities	0	144
Common Equity Securities [Member]
Marketable Securities [Line Items]
Equity Securities	73	201
Private Equity Funds [Member]
Marketable Securities [Line Items]
Equity Securities	$ 77	$ 60

Investments (Net Realized Inves

Investments (Net Realized Investment Gains/Losses) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Investment [Line Items]
Net realized gains (losses) on investments	$ 147	$ 30	$ 121	$ (48)
Fixed Maturities [Member]
Investment [Line Items]
Gross realized gains from sales	47	37	103	80
Gross realized losses from sales	(12)	(50)	(24)	(70)
Impairment recoveries (losses) recognized in income	2	27	1	(24)
Net realized gains (losses) from sales	37	14	80	(14)
Equity Securities [Member]
Investment [Line Items]
Gross realized gains from sales	23	64	28	65
Gross realized losses from sales	(5)	(19)	(76)	(70)
Net realized gains (losses) from sales	18	45	(48)	(5)
Other Investments [Member]
Investment [Line Items]
Impairment recoveries (losses) recognized in income	2	(29)	(6)	(35)
Gross realized gains from sales	90	0	95	6
Net realized gains (losses) from sales of other investments	$ 92	$ (29)	$ 89	$ (29)

Investments (Gains and Losses R

Investments (Gains and Losses Recognized on Equity Securities) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Schedule of losses and gains related to equity securities [Line Items]
Net realized gains (losses) on financial instruments	$ 172	$ 29	$ 168	$ (52)
Equity Securities [Member]
Schedule of losses and gains related to equity securities [Line Items]
Net realized gains (losses) on financial instruments	18	45	(48)	(5)
Equity Securities, Realized Gains (Losses) on Sales	1	20	(56)	5
Unrealized (losses) gains recognized on equity securities still held	$ 17	$ 25	$ 8	$ (10)

Investments (Securities Lending

Investments (Securities Lending Programs) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Fair Value of Collateral	$ 1,841	$ 1,199
Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Collateral received for securities loaned, at carrying value	1,841
Overnight and Continuous [Member] | Cash [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Collateral received for securities loaned, at carrying value	1,739
Overnight and Continuous [Member] | United States Government Securities [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Collateral received for securities loaned, at carrying value	$ 102

Investments (Narrative) (Detail

Investments (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Schedule of Investments [Line Items]
Accrued investment income receivable	$ 195	$ 188
Fair value of collateral received at time of securities lending transactions	$ 1,841	$ 1,199
Securities Lending Transactions Ratio of Fair Value of Collateral Held To Securities On Loan	102.00%

Derivative Financial Instrume_2

Derivative Financial Instruments (Financial Statement Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosures [Line Items]
AOCI, Cash Flow Hedge, Cumulative Gain (Loss), after Tax	$ (244)	$ (256)	$ (244)	$ (256)
Derivative, Gain (Loss) Recognized	25	$ (1)	47	$ (4)
Cash Flow Hedging [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
AOCI, Cash Flow Hedge, Cumulative Gain (Loss), after Tax	$ (244)		$ (244)		$ (250)

Fair Value (Fair Value Measurem

Fair Value (Fair Value Measurements By Level For Assets Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 2,044	$ 3,163
Equity Securities	1,746	1,559
Other invested assets	4,917	4,285
Securities lending collateral	1,841	1,199
Total assets	32,335	29,959
Total liabilities	(31)	(5)
Exchange Traded Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities	1,596	1,154
Fixed Maturity Mutual Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities	0	144
Common Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities	73	201
Private Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities	77	60
Fixed Maturities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	26,429	23,995
Fixed Maturities [Member] | United States Government Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	1,320	774
Fixed Maturities [Member] | Government Sponsored Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	65	69
Fixed Maturities [Member] | Foreign Government Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	350	305
Fixed Maturities [Member] | States, Municipalities And Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	5,483	5,579
Fixed Maturities [Member] | Corporate Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	12,176	10,892
Fixed Maturities [Member] | Residential Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	4,432	4,345
Fixed Maturities [Member] | Commercial Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	73	72
Fixed Maturities [Member] | Other Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	2,530	1,959
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities	1,746	1,559
Equity Securities [Member] | Exchange Traded Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities	1,596	1,154
Equity Securities [Member] | Fixed Maturity Mutual Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities		144
Equity Securities [Member] | Common Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities	73	201
Equity Securities [Member] | Private Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities	77	60
Other Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	4,733	4,285
Other Investments [Member] | Common Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	184
Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	91	43
Derivative liabilities	(31)	(5)
Level I [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	2,044	3,163
Securities lending collateral	0	0
Total assets	3,830	4,488
Total liabilities	0	0
Level I [Member] | Fixed Maturities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Level I [Member] | Fixed Maturities [Member] | United States Government Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Level I [Member] | Fixed Maturities [Member] | Government Sponsored Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Level I [Member] | Fixed Maturities [Member] | Foreign Government Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Level I [Member] | Fixed Maturities [Member] | States, Municipalities And Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Level I [Member] | Fixed Maturities [Member] | Corporate Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Level I [Member] | Fixed Maturities [Member] | Residential Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Level I [Member] | Fixed Maturities [Member] | Commercial Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Level I [Member] | Fixed Maturities [Member] | Other Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Level I [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities	1,602	1,325
Level I [Member] | Equity Securities [Member] | Exchange Traded Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities	1,596	1,154
Level I [Member] | Equity Securities [Member] | Fixed Maturity Mutual Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities		0
Level I [Member] | Equity Securities [Member] | Common Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities	6	171
Level I [Member] | Equity Securities [Member] | Private Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities	0	0
Level I [Member] | Other Investments [Member] | Common Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	184
Level I [Member] | Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Level II [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Securities lending collateral	1,841	1,199
Total assets	28,068	25,079
Total liabilities	(31)	(5)
Level II [Member] | Fixed Maturities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	26,069	23,663
Level II [Member] | Fixed Maturities [Member] | United States Government Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	1,320	774
Level II [Member] | Fixed Maturities [Member] | Government Sponsored Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	65	69
Level II [Member] | Fixed Maturities [Member] | Foreign Government Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	350	305
Level II [Member] | Fixed Maturities [Member] | States, Municipalities And Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	5,483	5,579
Level II [Member] | Fixed Maturities [Member] | Corporate Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	11,825	10,567
Level II [Member] | Fixed Maturities [Member] | Residential Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	4,430	4,343
Level II [Member] | Fixed Maturities [Member] | Commercial Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	73	72
Level II [Member] | Fixed Maturities [Member] | Other Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	2,523	1,954
Level II [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities	67	174
Level II [Member] | Equity Securities [Member] | Exchange Traded Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities	0	0
Level II [Member] | Equity Securities [Member] | Fixed Maturity Mutual Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities		144
Level II [Member] | Equity Securities [Member] | Common Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities	67	30
Level II [Member] | Equity Securities [Member] | Private Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities	0	0
Level II [Member] | Other Investments [Member] | Common Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0
Level II [Member] | Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	91	43
Derivative liabilities	(31)	(5)
Level III [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Securities lending collateral	0	0
Total assets	437	392
Total liabilities	0	0
Level III [Member] | Fixed Maturities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	360	332
Level III [Member] | Fixed Maturities [Member] | United States Government Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Level III [Member] | Fixed Maturities [Member] | Government Sponsored Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Level III [Member] | Fixed Maturities [Member] | Foreign Government Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Level III [Member] | Fixed Maturities [Member] | States, Municipalities And Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Level III [Member] | Fixed Maturities [Member] | Corporate Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	351	325
Level III [Member] | Fixed Maturities [Member] | Residential Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	2	2
Level III [Member] | Fixed Maturities [Member] | Commercial Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Level III [Member] | Fixed Maturities [Member] | Other Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	7	5
Level III [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities	77	60
Level III [Member] | Equity Securities [Member] | Exchange Traded Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities	0	0
Level III [Member] | Equity Securities [Member] | Fixed Maturity Mutual Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities		0
Level III [Member] | Equity Securities [Member] | Common Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities	0	0
Level III [Member] | Equity Securities [Member] | Private Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities	77	60
Level III [Member] | Other Investments [Member] | Common Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0
Level III [Member] | Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	$ 0	$ 0

Fair Value (Reconciliation Of T

Fair Value (Reconciliation Of The Beginning And Ending Balances Of Assets Measured At Fair Value On A Recurring Basis Using Level III Inputs) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 396	$ 405	$ 392	$ 397
Total gains (losses) recognized in net income	5	(9)	13	(17)
Total gains (losses) recognized in accumulated other comprehensive loss	3	(7)	6	(17)
Purchases	75	17	114	54
Sales	(10)	(14)	(15)	(26)
Settlements	(32)	(9)	(73)	(21)
Transfers into Level III				13
Ending balance	437	383	437	383
Change in unrealized gains (losses) included in net income related to assets still held	5	(10)	13	(17)
Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	324	316	325	303
Total gains (losses) recognized in net income	0	1	0	(1)
Total gains (losses) recognized in accumulated other comprehensive loss	3	(7)	6	(17)
Purchases	65	14	104	39
Sales	(9)	(1)	(11)	(4)
Settlements	(32)	(9)	(73)	(19)
Transfers into Level III				13
Ending balance	351	314	351	314
Change in unrealized gains (losses) included in net income related to assets still held	0	0	0	0
Residential Mortgage-Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	2	2	2	2
Total gains (losses) recognized in net income	0	0	0	0
Total gains (losses) recognized in accumulated other comprehensive loss	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements	0	0	0	0
Transfers into Level III				0
Ending balance	2	2	2	2
Change in unrealized gains (losses) included in net income related to assets still held	0	0	0	0
Other Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	5	5	5	7
Total gains (losses) recognized in net income	0	0	0	0
Total gains (losses) recognized in accumulated other comprehensive loss	0	0	0	0
Purchases	2	0	2	0
Sales	0	0	0	0
Settlements	0	0	0	(2)
Transfers into Level III				0
Ending balance	7	5	7	5
Change in unrealized gains (losses) included in net income related to assets still held	0	0	0	0
Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	65	82	60	85
Total gains (losses) recognized in net income	5	(10)	13	(16)
Total gains (losses) recognized in accumulated other comprehensive loss	0	0	0	0
Purchases	8	3	8	15
Sales	(1)	(13)	(4)	(22)
Settlements	0	0	0	0
Transfers into Level III				0
Ending balance	77	62	77	62
Change in unrealized gains (losses) included in net income related to assets still held	$ 5	$ (10)	$ 13	$ (17)

Fair Value (Carrying And Estima

Fair Value (Carrying And Estimated Fair Values by Level Of Financial Instruments Not Recorded At Fair Value On Consolidated Balance Sheet) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	$ 4,917	$ 4,285
Short-term borrowings	175	0
Commercial paper	550	250
Notes	25,425	23,307
Convertible debentures	610	712
Fair Value, Recurring [Member] | Level III [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term borrowings	0
Commercial paper	0	0
Notes	0	0
Convertible debentures	0	0
Fair Value, Recurring [Member] | Level II [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets		0
Short-term borrowings	175
Commercial paper	550	250
Notes	25,425	23,307
Convertible debentures	610	712
Fair Value, Recurring [Member] | Level I [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term borrowings	0
Commercial paper	0	0
Notes	0	0
Convertible debentures	0	0
Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term borrowings	175
Commercial paper	550	250
Notes	22,439	19,677
Convertible debentures	77	108
Other Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	4,733	4,285
Other Investments [Member] | Fair Value, Recurring [Member] | Level III [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	4,733	4,285
Other Investments [Member] | Fair Value, Recurring [Member] | Level II [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0
Other Investments [Member] | Fair Value, Recurring [Member] | Level I [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Other Investments [Member] | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	$ 4,733	$ 4,285

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income tax expense	$ 552	$ 873	$ 1,061	$ 1,439
Effective tax rate	23.50%	27.70%	23.40%	27.50%
Income taxes receivable	$ 156		$ 156		$ 262

Medical Claims Payable (Reconci

Medical Claims Payable (Reconciliation Of The Beginning And Ending Balances For Medical Claims Payable By Segment) (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Medical Claims Payable [Line Items]
Gross medical claims payable, beginning of period		$ 11,135		$ 8,647	$ 11,135	$ 8,647
Ceded medical claims payable, beginning of period		(46)		(33)	(46)	(33)
Net medical claims payable, beginning of period		11,089		8,614	11,089	8,614
Business combinations and purchase adjustments	$ 420		$ 339		420	339
Current period net incurred medical claims					48,343	39,978
Prior periods redundancies					(1,772)	(700)
Total net incurred medical claims	23,844	22,727	18,748	20,530	46,571	39,278
Net payments attributable to current period medical claims					37,533	31,625
Net payments attributable to prior periods medical claims					7,767	7,041
Total net payments					45,300	38,666
Net medical claims payable, end of period	12,780		9,565		12,780	9,565
Ceded medical claims payable, end of period	41		90		41	90
Gross medical claims payable, end of period	12,821		9,655		12,821	9,655
Commercial Specialty Business Segment [Member]
Medical Claims Payable [Line Items]
Gross medical claims payable, beginning of period		3,294		3,039	3,294	3,039
Ceded medical claims payable, beginning of period		(13)		(14)	(13)	(14)
Net medical claims payable, beginning of period		3,281		3,025	3,281	3,025
Business combinations and purchase adjustments	0		0		0	0
Current period net incurred medical claims					13,360	11,318
Prior periods redundancies					(570)	(374)
Total net incurred medical claims	6,718	6,072	5,147	5,797	12,790	10,944
Net payments attributable to current period medical claims					10,295	9,014
Net payments attributable to prior periods medical claims					2,154	2,218
Total net payments					12,449	11,232
Net medical claims payable, end of period	3,622		2,737		3,622	2,737
Ceded medical claims payable, end of period	11		62		11	62
Gross medical claims payable, end of period	3,633		2,799		3,633	2,799
Government Business Segment [Member]
Medical Claims Payable [Line Items]
Gross medical claims payable, beginning of period		7,646		5,608	7,646	5,608
Ceded medical claims payable, beginning of period		(33)		(19)	(33)	(19)
Net medical claims payable, beginning of period		7,613		5,589	7,613	5,589
Business combinations and purchase adjustments	375		141		375	141
Current period net incurred medical claims					34,232	28,162
Prior periods redundancies					(1,190)	(326)
Total net incurred medical claims	16,723	16,319	13,233	14,603	33,042	27,836
Net payments attributable to current period medical claims					26,647	22,115
Net payments attributable to prior periods medical claims					5,455	4,823
Total net payments					32,102	26,938
Net medical claims payable, end of period	8,928		6,628		8,928	6,628
Ceded medical claims payable, end of period	30		28		30	28
Gross medical claims payable, end of period	8,958		6,656		8,958	6,656
Other Segment [Member]
Medical Claims Payable [Line Items]
Gross medical claims payable, beginning of period		195		0	195	0
Ceded medical claims payable, beginning of period		0		0	0	0
Net medical claims payable, beginning of period		195		0	195	0
Business combinations and purchase adjustments	45		198		45	198
Current period net incurred medical claims					751	498
Prior periods redundancies					(12)	0
Total net incurred medical claims	403	$ 336	368	$ 130	739	498
Net payments attributable to current period medical claims					591	496
Net payments attributable to prior periods medical claims					158	0
Total net payments					749	496
Net medical claims payable, end of period	230		200		230	200
Ceded medical claims payable, end of period	0		0		0	0
Gross medical claims payable, end of period	$ 230		$ 200		$ 230	$ 200

Medical Claims Payable (Recon_2

Medical Claims Payable (Reconciliation Of Net Incurred Medical Claims To Benefit Expense) (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Reconciliation of net incurred medical claims to benefit expense [Line Items]
Total net incurred medical claims	$ 23,844	$ 22,727	$ 18,748	$ 20,530	$ 46,571	$ 39,278
Quality improvement and other claims expense	919	972	799	959	1,891	1,758
Benefit expense	24,763	23,699	19,547	21,489	48,462	41,036
Commercial Specialty Business Segment [Member]
Reconciliation of net incurred medical claims to benefit expense [Line Items]
Total net incurred medical claims	6,718	6,072	5,147	5,797	12,790	10,944
Government Business Segment [Member]
Reconciliation of net incurred medical claims to benefit expense [Line Items]
Total net incurred medical claims	16,723	16,319	13,233	14,603	33,042	27,836
Other Segment [Member]
Reconciliation of net incurred medical claims to benefit expense [Line Items]
Total net incurred medical claims	$ 403	$ 336	$ 368	$ 130	$ 739	$ 498

Medical Claims Payable Medical

Medical Claims Payable Medical Claims Payable (Reconciliation of the Claims Development to the Claims Liability) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net medical claims payable, end of period	$ 12,780	$ 11,089		$ 8,614
Ceded medical claims payable end of period	41	46	$ 90	33
Insurance lines other than short duration	255
Gross medical claims payable, end of period	13,076	11,359
Commercial Specialty Business Segment [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net medical claims payable, end of period	3,622	3,281		3,025
Ceded medical claims payable end of period	11	13	62	14
Insurance lines other than short duration	0
Gross medical claims payable, end of period	3,633
Government Business Segment [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net medical claims payable, end of period	8,928	7,613		5,589
Ceded medical claims payable end of period	30	33	28	19
Insurance lines other than short duration	255
Gross medical claims payable, end of period	9,213
Other Segment [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net medical claims payable, end of period	230	195		0
Ceded medical claims payable end of period	0	$ 0	$ 0	$ 0
Insurance lines other than short duration	0
Gross medical claims payable, end of period	$ 230

Medical Claims Payable (Narrati

Medical Claims Payable (Narrative) (Details) $ in Millions	Jun. 30, 2021USD ($)
Short-Duration Insurance Contract, Accident Year 2019 [Member] | Commercial Specialty Business Segment [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 71
Short-Duration Insurance Contract, Accident Year 2019 [Member] | Government Business Segment [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	105
Short-Duration Insurance Contract, Accident Year 2019 [Member] | Other Segment [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	0
Short-Duration Insurance Contract, Accident Year 2020 [Member] | Commercial Specialty Business Segment [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	486
Short-Duration Insurance Contract, Accident Year 2020 [Member] | Government Business Segment [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	862
Short-Duration Insurance Contract, Accident Year 2020 [Member] | Other Segment [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	25
Short-Duration Insurance Contract, Accident Year 2021 [Member] | Commercial Specialty Business Segment [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	3,065
Short-Duration Insurance Contract, Accident Year 2021 [Member] | Government Business Segment [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	7,961
Short-Duration Insurance Contract, Accident Year 2021 [Member] | Other Segment [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 205

Debt (Convertible Debenture Det

Debt (Convertible Debenture Details) (Details) $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2021USD ($)$ / shares	Dec. 31, 2020USD ($)
Debt Instrument [Line Items]
Net debt carrying amount	$ 610	$ 712
Convertible Debt [Member]
Debt Instrument [Line Items]
Outstanding principal amount	113
Unamortized debt discount	35
Net debt carrying amount	78
Equity component carrying amount	$ 41
Conversion rate (shares of common stock per $1,000 of principal)	14.1462
Effective conversion price (per $1,000 of principal amount) per share | $ / shares	$ 70.6904

Debt (Narrative) (Details)

Debt (Narrative) (Details) - USD ($) $ in Millions	May 15, 2021	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Mar. 17, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Repayments of Long-term Debt				$ 952	$ 155
Loss on extinguishment of debt		$ 5	$ 3	5	$ 4
Short-term borrowings		175		175			$ 0
Commercial paper		550		$ 550			250
One Point Five Zero Percent Due Two Thousand Twenty Six [Member]
Debt Instrument [Line Items]
Debt instrument interest rate						1.50%
Debt Instrument, Face Amount						$ 750
Two Point Five Five Zero Percent Due Two Thousand Thirty One [Member]
Debt Instrument [Line Items]
Debt instrument interest rate						2.55%
Debt Instrument, Face Amount						$ 1,000
Three Point Six Zero Percent Due Two Thousand Fifty One [Member]
Debt Instrument [Line Items]
Debt instrument interest rate						3.60%
Debt Instrument, Face Amount						$ 1,250
Zero Point Four Five Zero Percent Due Two Thousand Twenty Three [Member]
Debt Instrument [Line Items]
Debt instrument interest rate						0.45%
Debt Instrument, Face Amount						$ 500
Three Point Seven Zero Zero Percent Due Two Thousand Twenty One [Member]
Debt Instrument [Line Items]
Debt instruments, repurchased face amount	$ 700
Debt instrument interest rate	3.70%
Debt Instrument, Redemption, Description	at a redemption price equal to 100% of the aggregate principal amount of the notes being redeemed, plus accrued and unpaid interest.
Senior Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Covenant description				Our ability to borrow under these Credit Facilities is subject to compliance with certain covenants, including covenants requiring us to maintain a defined debt-to-capital ratio of not more than 60%, subject to increase in certain circumstances set forth in the applicable credit agreement.
Covenant compliance				As of June 30, 2021, our debt-to-capital ratio, as defined and calculated under the Credit Facilities, was 39.9%. We do not believe the restrictions contained in any of our Credit Facility covenants materially affect our financial or operating flexibility. As of June 30, 2021, we were in compliance with all of the debt covenants under these Credit Facilities.
Convertible Debt [Member]
Debt Instrument [Line Items]
Loss on extinguishment of debt		5		$ 5
Extinguishment of Debt, Amount		46		46
Payment for Debt Extinguishment or Debt Prepayment Cost		252		253
Lines of Credit [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		300		300
Federal Home Loan Bank Advances [Member]
Debt Instrument [Line Items]
Federal Home Loan Bank, advances, short-term		175		175			0
Surplus Notes [Member]
Debt Instrument [Line Items]
Long-term Debt		25		25			25
Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Long-term Debt		22,414		22,414			19,652
Commercial Paper Program
Debt Instrument [Line Items]
Commercial paper authorized		3,500		3,500
Commercial paper		550		550			$ 250
New 364-Day Facility [Member] | Senior Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		1,000		1,000
5-Year Facility [Member] | Senior Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 2,500		$ 2,500

Commitments And Contingencies (

Commitments And Contingencies (Details) $ in Millions	6 Months Ended
	Jun. 30, 2021USD ($)states	Mar. 31, 2021USD ($)	Dec. 31, 2020USD ($)
Commitments And Contingencies [Line Items]
Gross premium tax rate, state of California	2.35%
Merger agreement, termination fee		$ 1,850
Long-term purchase commitment, amount	$ 1,166
Minimum [Member]
Commitments And Contingencies [Line Items]
Estimate of possible loss on loss contingencies	0
Maximum [Member]
Commitments And Contingencies [Line Items]
Estimate of possible loss on loss contingencies	$ 250
BCBS Antitrust Litigation [Member]
Commitments And Contingencies [Line Items]
Number of states action filed | states	28
Estimate of possible loss on loss contingencies	$ 507		$ 594
Anthem, Inc. v. Express Scripts, Inc. [Member]
Commitments And Contingencies [Line Items]
Proceeds originally received at time of divestiture	4,675
Anthem, Inc. v. Express Scripts, Inc. [Member] | Damages for Pharmacy Pricing [Member]
Commitments And Contingencies [Line Items]
Approximate amount of damages sought for breaches	14,800
Anthem, Inc. v. Express Scripts, Inc. [Member] | Damages for Operational Breaches [Member]
Commitments And Contingencies [Line Items]
Approximate amount of damages sought for breaches	$ 158

Capital Stock (Summary of Cash

Capital Stock (Summary of Cash Dividend Activity) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Banking Regulation, Total Capital [Abstract]
Declaration date	Apr. 20, 2021	Jan. 26, 2021	Apr. 28, 2020	Jan. 28, 2020
Record date	Jun. 10, 2021	Mar. 10, 2021	Jun. 10, 2020	Mar. 16, 2020
Payment date	Jun. 25, 2021	Mar. 25, 2021	Jun. 25, 2020	Mar. 27, 2020
Cash dividends per share	$ 1.13	$ 1.13	$ 0.95	$ 0.95
Total payment	$ 278	$ 277	$ 242	$ 240	$ 555	$ 482

Capital Stock (Summary of Share

Capital Stock (Summary of Share Repurchases) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Equity, Class of Treasury Stock [Line Items]
Shares repurchased					2.7	2.1
Average price per share					$ 346.47	$ 273.72
Aggregate cost	$ 480	$ 447	$ 55	$ 529	$ 927	$ 584
Authorization remaining at the end of the period	$ 5,165		$ 3,208		$ 5,165	$ 3,208

Capital Stock (Summary of Stock

Capital Stock (Summary of Stock Option Activity) (Details) $ / shares in Units, shares in Millions, $ in Millions	6 Months Ended
	Jun. 30, 2021USD ($)$ / sharesshares
Number of Shares [Roll Forward]
Outstanding at beginning of period, Number of Shares | shares	3.1
Granted, Number of Shares | shares	0.7
Exercised, Number of Shares | shares	(0.6)
Forfeited or expired, Number of Shares | shares	(0.1)
Outstanding at end of period, Number of Shares | shares	3.1
Exercisable at end of period, Number of Shares | shares	1.6
Weighted-Average Option Price Per Share [Roll Forward]
Outstanding at beginning of period, Weighted-Average Option Price per Share | $ / shares	$ 230
Granted, Weighted-Average Option Price per Share | $ / shares	312.33
Exercised, Weighted-Average Option Price per Share | $ / shares	193.55
Forfeited or expired, Weighted-Average Option Price per Share | $ / shares	286.70
Outstanding at end of period, Weighted-Average Option Price per Share | $ / shares	253.91
Exercisable at end of period, Weighted-Average Option Price per Share | $ / shares	$ 215.56
Outstanding at end of period, Weighted-Average Remaining Contractual Life	7 years 2 months 23 days
Exercisable at end of period, Weighted-Average Remaining Contractual Life	5 years 11 months 8 days
Outstanding at end of period, Aggregate Intrinsic Value | $	$ 402
Exercisable at end of period, Aggregate Intrinsic Value | $	$ 270

Capital Stock (Nonvested Restri

Capital Stock (Nonvested Restricted Stock Activity Including Restricted Stock Units) (Details) - $ / shares shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Restricted Stock Shares and Units [Roll Forward]
Nonvested at Beginning Balance, Restricted Stock Shares and Units			1.3
Granted, Restricted Stock Shares and Units	0	0.1	0.9	1.3
Vested, Restricted Stock Shares And Units			(0.8)
Forfeited, Restricted Stock Shares And Units			(0.1)
Nonvested at Ending Balance, Restricted Stock Shares and Units	1.3		1.3
Weighted-Average Grant Date Fair Value Per Share [Roll Forward]
Nonvested at Beginning Balance, Weighted-Average Grant Date Fair Value per Share			$ 272.51
Granted, Weighted-Average Grant Date Fair Value per Share			312.50	$ 272.14
Vested, Weighted-Average Grant Date Fair Value per Share			244.24
Forfeited, Weighted-Average Grant Date Fair Value per Share			287.67
Nonvested at Ending Balance, Weighted-Average Grant Date Fair Value per Share	$ 295.57		$ 295.57

Capital Stock (Fair Values of O

Capital Stock (Fair Values of Options Granted During The Period Estimated Using Weighted-Average Assumptions) (Details)	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Banking Regulation, Total Capital [Abstract]
Risk-free interest rate	1.44%	1.30%
Volatility factor	30.00%	26.00%
Quarterly dividend yield	0.36%	0.35%
Weighted-average expected life (years)	5 years 6 months	4 years 3 months 18 days

Capital Stock (Schedule Of Weig

Capital Stock (Schedule Of Weighted-Average Fair Values Determined For The Periods) (Details) - $ / shares	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Banking Regulation, Total Capital [Abstract]
Options granted during the period	$ 79.22	$ 54.04
Restricted stock awards granted during the period	$ 312.50	$ 272.14

Capital Stock (Narrative) (Deta

Capital Stock (Narrative) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	Sep. 24, 2021	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jul. 20, 2021	Jan. 26, 2021
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Dividends Payable, Date to be Paid		Jun. 25, 2021	Mar. 25, 2021	Jun. 25, 2020	Mar. 27, 2020
Dividends Payable, Date of Record		Jun. 10, 2021	Mar. 10, 2021	Jun. 10, 2020	Mar. 16, 2020
Increase In Stock Repurchase Program Authorization								$ 5,000
Subsequent Event [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Dividends Payable, Amount Per Share							$ 1.13
Dividends Payable, Date to be Paid	Sep. 24, 2021
Dividends Payable, Date of Record	Sep. 10, 2021
2021 to 2023 [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross						0.3
2018 to 2020 [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross						0.3

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss (Reconciliation Of The Components Of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Investments, Accumulated Gross Unrealized Gain, before Tax	$ 1,095	$ 974
Investments, Accumulated Gross Unrealized Loss, before Tax	(89)	(229)
Investments, Accumulated Gross Unrealized Gain (Loss), before Tax	1,006	745
Deferred tax (liability) asset	(240)	(183)
Investments, Accumulated Adjustment for Noncontrolling Interest	(4)	0
Investments, Accumulated Net Unrealized Gains (Losses), after Tax	762	562
Accumulated other comprehensive income (loss), non-credit component of impairments on investments	0	(32)
Non-Credit Component of Impairments on Investments In Accumulated Other Comprehensive Income Deferred Tax Liability Asset	0	8
Accumulated Other Comprehensive Income Loss Non-Credit Component of Impairment Loss on Investments Net Of Tax	0	(24)
Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss)	(308)	(323)
Cash flow hedges, deferred tax asset	64	67
AOCI, Cash Flow Hedge, Cumulative Gain (Loss), after Tax	(244)	(256)
Defined benefit pension plans, deferred net actuarial loss	(723)	(707)
Defined benefit pension plans, deferred prior service credits	0	(1)
Defined benefit pension plans, deferred tax asset	184	181
Defined Benefit Plan Accumulated Other Comprehensive Income Adjustments Net Of Tax	(539)	(527)
Postretirement benefit plans, deferred net actuarial loss	(3)	(25)
Deferred Prior Service Cost (Credit) Postretirement Benefit Plans	10	16
Deferred Tax Liability, Postretirement Benefits	(2)
Postretirement benefit plans, deferred tax asset		2
Net unrecognized periodic benefit credit (costs) for postretirement benefit plans	5	(7)
Foreign currency translation adjustments, gross unrealized losses	(1)	(3)
Deferred Tax Liabilities, Unrealized Currency Transaction Gains	0
Foreign currency translation adjustments, deferred tax asset		1
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	(1)	(2)
Accumulated other comprehensive loss	$ (17)	$ (254)	$ 150

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Income (Other Comprehensive Income (Loss) Reclassification Adjustments) (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Change in net unrealized gains/losses on investments	$ 201		$ 741		$ (125)	$ 33
Reclassification adjustment for net realized loss (gain) on investment securities, net of tax	(26)		(11)		(62)	8
Total reclassification adjustment on investments	175		730		(187)	41
Change in non-credit component of impairment losses on investments net of tax	1		10		2	(22)
Cash flow hedges, holding gain (loss), net of tax	2		3		6	6
Net change in unrecognized periodic benefit costs for defined benefit pension and postretirement benefit plans, net of tax	8		10		18	17
Foreign currency translation adjustment, net of tax	(6)		1		(6)	0
Other comprehensive income (loss)	180	$ (347)	754	$ (712)	(167)	42
Other comprehensive income attributable to noncontrolling interests	(2)		0		0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent, Total	$ 178		$ 754		$ (167)	$ 42

Accumulated Other Comprehensi_5

Accumulated Other Comprehensive Income (Loss) Accumulated Other Comprehensive Income Reclassification Adjustments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Accumulated Other Comprehensive Income (Loss) Reclassification Adjustments (Parantheticals) [Abstract]
Net holding gain (loss) on investment securities arising during the period, tax (expense) benefit	$ (61)	$ (238)	$ 46	$ (23)
Reclassification adjustment for net realized loss (gain) on investment securities, tax (benefit) expense	7	4	16	(5)
Tax (expense) benefit of non credit impairment on available-for-sale securities recognized in other comprehensive income (loss)	0	(2)	(1)	7
Cash flow hedges, holding gain (loss), tax (expense) benefit	(1)	(1)	(2)	(2)
Net change in unrecognized periodic benefit costs for defined benefit pension and postretirement benefit plans, tax expense	(2)	(4)	(6)	(7)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	1	0	1	0
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	(56)	(241)	54	(30)
Other Comprehensive Income (Loss), Tax, Portion Attributable to Noncontrolling Interest	1	0	1	0
Net gain (loss) recognized in other comprehensive income, tax (expense) benefit	$ (55)	$ (241)	$ 55	$ (30)

Earnings Per Share (Denominator

Earnings Per Share (Denominator For Basic And Diluted Earnings Per Share) (Details) - shares shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Denominator for basic earnings per share - weighted-average shares	244.5	252.2	244.8	252.3
Effect of dilutive securities – employee stock options, nonvested restricted stock awards and convertible debentures	2.9	3.2	3	3.6
Denominator for diluted earnings per share	247.4	255.4	247.8	255.9

Earnings Per Share (Narrative)

Earnings Per Share (Narrative) (Details) - shares shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Weighted average shares excluded from denominator for diluted earnings per share because the stock options were anti-dilutive	0.3	1.6	0.4	1.3
Restricted stock units issued under stock incentive plan	0	0.1	0.9	1.3
Restricted stock units excluded from the denominator for diluted earnings per share			0.3	0.2

Segment Information (Financial

Segment Information (Financial Data By Reportable Segment) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Segment Reporting Information [Line Items]
Reportable segments operating revenues	$ 33,279	$ 29,178	$ 65,377	$ 58,626
Operating gain (loss)	2,081	3,360	4,242	5,554
Commercial & Specialty [Member]
Segment Reporting Information [Line Items]
Operating gain (loss)	791	1,372	2,059	2,792
Government Business [Member]
Segment Reporting Information [Line Items]
Operating gain (loss)	868	1,618	1,346	2,029
IngenioRx Segment [Member]
Segment Reporting Information [Line Items]
Operating gain (loss)	405	304	812	653
Other [Member]
Segment Reporting Information [Line Items]
Operating gain (loss)	17	66	25	80
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Reportable segments operating revenues	(5,073)	(3,574)	(9,981)	(7,177)
Unaffiliated
Segment Reporting Information [Line Items]
Reportable segments operating revenues	33,279	29,178	65,377	58,626
Unaffiliated | Commercial & Specialty [Member]
Segment Reporting Information [Line Items]
Reportable segments operating revenues	9,550	8,789	19,041	18,150
Unaffiliated | Government Business [Member]
Segment Reporting Information [Line Items]
Reportable segments operating revenues	20,066	17,242	39,349	34,708
Unaffiliated | IngenioRx Segment [Member]
Segment Reporting Information [Line Items]
Reportable segments operating revenues	3,042	2,544	5,780	4,887
Unaffiliated | Other [Member]
Segment Reporting Information [Line Items]
Reportable segments operating revenues	621	603	1,207	881
Affiliated [Member]
Segment Reporting Information [Line Items]
Reportable segments operating revenues	0	0	0	0
Affiliated [Member] | Commercial & Specialty [Member]
Segment Reporting Information [Line Items]
Reportable segments operating revenues		0	0	0
Affiliated [Member] | Government Business [Member]
Segment Reporting Information [Line Items]
Reportable segments operating revenues		0	0	0
Affiliated [Member] | IngenioRx Segment [Member]
Segment Reporting Information [Line Items]
Reportable segments operating revenues	3,177	2,725	6,301	5,579
Affiliated [Member] | Other [Member]
Segment Reporting Information [Line Items]
Reportable segments operating revenues	$ 1,896	$ 849	$ 3,680	$ 1,598

Segment Information Segment Inf

Segment Information Segment Information (Major Product Revenues for Each Reportable Segment) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Major Product Revenue By Segment [Line Items]
Insurance Services Revenue	$ 33,279	$ 29,178	$ 65,377	$ 58,626
Commercial Specialty Business Segment [Member]
Major Product Revenue By Segment [Line Items]
Insurance Services Revenue	9,550	8,789	19,041	18,150
Government Business Segment [Member]
Major Product Revenue By Segment [Line Items]
Insurance Services Revenue	20,066	17,242	39,349	34,708
IngenioRx Segment [Member]
Major Product Revenue By Segment [Line Items]
Insurance Services Revenue	6,219	5,269	12,081	10,466
Other Segment [Member]
Major Product Revenue By Segment [Line Items]
Insurance Services Revenue	2,517	1,452	4,887	2,479
Segment Eliminations [Member]
Major Product Revenue By Segment [Line Items]
Insurance Services Revenue	(5,073)	(3,574)	(9,981)	(7,177)
Managed Care Products [Member] | Commercial Specialty Business Segment [Member]
Major Product Revenue By Segment [Line Items]
Insurance Services Revenue	7,772	7,132	15,461	14,700
Managed Care Products [Member] | Government Business Segment [Member]
Major Product Revenue By Segment [Line Items]
Insurance Services Revenue	19,965	17,149	39,147	34,524
Managed Care Services [Member] | Commercial Specialty Business Segment [Member]
Major Product Revenue By Segment [Line Items]
Insurance Services Revenue	1,416	1,263	2,802	2,645
Managed Care Services [Member] | Government Business Segment [Member]
Major Product Revenue By Segment [Line Items]
Insurance Services Revenue	101	93	202	184
Dental Vision Products And Services [Member] | Commercial Specialty Business Segment [Member]
Major Product Revenue By Segment [Line Items]
Insurance Services Revenue	335	284	671	599
Other Products [Member] | Commercial Specialty Business Segment [Member]
Major Product Revenue By Segment [Line Items]
Insurance Services Revenue	27	110	107	206
Other Products [Member] | Other Segment [Member]
Major Product Revenue By Segment [Line Items]
Insurance Services Revenue	151	76	272	154
Pharmacy products and services [Member] | IngenioRx Segment [Member]
Major Product Revenue By Segment [Line Items]
Insurance Services Revenue	6,219	5,269	12,081	10,466
Integrated health services | Other Segment [Member]
Major Product Revenue By Segment [Line Items]
Insurance Services Revenue	$ 2,366	$ 1,376	$ 4,615	$ 2,325

Segment Information (Reconcilia

Segment Information (Reconciliation Of Reportable Segments Operating Revenues To Total Revenues Reported In The Consolidated Statements Of Income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Segment Reporting [Abstract]
Reportable segments operating revenues	$ 33,279	$ 29,178	$ 65,377	$ 58,626
Net investment income	400	57	691	311
Net realized gains (losses) on financial instruments	172	29	168	(52)
Total revenues	$ 33,851	$ 29,264	$ 66,236	$ 58,885

Segment Information (Reconcil_2

Segment Information (Reconciliation Of Reportable Segments Operating Gain To Income Before Income Tax Expense Included In The Consolidated Statements Of Income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Segment Reporting [Abstract]
Reportable segments operating gain	$ 2,081	$ 3,360	$ 4,242	$ 5,554
Net investment income	400	57	691	311
Net realized gains (losses) on financial instruments	172	29	168	(52)
Interest expense	(205)	(201)	(397)	(395)
Amortization of other intangible assets	(90)	(93)	(170)	(176)
(Loss) gain on extinguishment of debt	(5)	(3)	(5)	(4)
Income before income tax expense	$ 2,353	$ 3,149	$ 4,529	$ 5,238

Segment Information Segment I_2

Segment Information Segment Information (Narrative) (Details)	6 Months Ended
	Jun. 30, 2021segment
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Number of Reportable Segments	4

Leases (Lease and Other Informa

Leases (Lease and Other Information) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Operating Lease, Cost	$ 34	$ 59	$ 63	$ 106
Short-term Lease, Cost	12	14	24	27
Sublease Income	(1)	(4)	(2)	(7)
Lease, Cost	45	69	85	126
Operating Lease, Payments	36	46	88	90
Right-of-use assets obtained in exchange for new operating lease liabilities	145	$ 33	160	$ 356
Other Noncurrent Assets [Member]
Operating Lease, Right-of-Use Asset	683		683		$ 646
Other Current Liabilities [Member]
Operating Lease, Liability, Current	144		144		110
Other Noncurrent Liabilities [Member]
Operating Lease, Liability, Noncurrent	$ 833		$ 833		$ 847

Leases (Reconciliation of Futur

Leases (Reconciliation of Future Lease Payments to Total Lease Liabilities) (Details) $ in Millions	Jun. 30, 2021USD ($)
Leases (Reconciliation of Future Lease Payments to Total Lease Liabilities) [Abstract]
Operating lease payments, 2021; excluding the six months ended June 30, 2021	$ 105
Operating lease payments, 2022	198
Operating lease payments, 2023	175
Operating lease payments, 2024	146
Operating lease payments, 2025	105
Operating lease payments, Thereafter	324
Total future minimum payments	1,053
Imputed Interest, Leases	(76)
Operating Lease Liabilities	$ 977

Leases (Narrative) (Details)

Leases (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Operating Lease, Weighted Average Remaining Lease Term	7 years	7 years
Weighted Average Discount Rate, Percent	2.86%	3.21%
Lessee, Operating Lease, Not yet Commenced, Description [Abstract]
Lessee, Operating Lease, Lease Not yet Commenced, Term of Contract	11 years
Lessee, Operating Lease, Lease Not yet Commenced, Description	are expected to commence on various dates during 2021 when the construction is complete and we take possession of the buildings
Lessee, Operating Lease, Lease Not Yet Commenced Expense	$ 65
Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	1 year
Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	13 years