UnitedHealth (UNH) 10-Q 6 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information Document	3 Months Ended
	Mar. 31, 2015	Apr. 30, 2015
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Entitiy Registrant Name	UNITEDHEALTH GROUP INC
Entitiy Central Index Key	731766
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		951,904,261

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Current assets:
Cash and cash equivalents	$8,650	$7,495
Short-term investments	1,780	1,741
Accounts receivable, net	5,040	4,252
Other current receivables, net	5,346	5,498
Assets under management	2,921	2,962
Deferred income taxes	405	556
Prepaid expenses and other current assets	2,632	1,052
Total current assets	26,774	23,556
Long-term investments	19,416	18,827
Property, equipment and capitalized software, net	4,245	4,418
Goodwill	32,782	32,940
Other intangible assets, net	3,441	3,669
Other assets	3,061	2,972
Total assets	89,719	86,382
Current liabilities:
Medical costs payable	13,537	12,040
Accounts payable and accrued liabilities	10,518	9,247
Other policy liabilities	6,392	5,965
Commercial paper and current maturities of long-term debt	2,797	1,399
Unearned revenues	1,734	1,972
Total current liabilities	34,978	30,623
Long-term debt, less current maturities	15,577	16,007
Future policy benefits	2,483	2,488
Deferred income taxes	2,056	2,065
Other liabilities	1,295	1,357
Total liabilities	56,389	52,540
Commitments and contingencies (Note 9)
Redeemable noncontrolling interests	1,452	1,388
Shareholders' equity:
Preferred stock, $0.001 par value - 10 shares authorized; no shares issued or outstanding	0	0
Common stock, $0.01 par value - 3,000 shares authorized; 952 and 954 issued and outstanding	10	10
Retained earnings	34,153	33,836
Accumulated other comprehensive loss	-2,285	-1,392
Total shareholders' equity	31,878	32,454
Total liabilities and shareholders’ equity	$89,719	$86,382

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheet (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, except Per Share data, unless otherwise specified
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	3,000	3,000
Common stock, shares issued	952	954
Common stock, shares outstanding	952	954
Preferred stock, par value	$0.00	$0.00
Preferred stock, shares authorized	10	10
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Revenues:
Premiums	$31,674	$28,115
Services	2,706	2,404
Products	1,230	998
Investment and other income	146	191
Total revenues	35,756	31,708
Operating costs:
Medical costs	25,689	23,208
Operating costs	5,949	5,194
Cost of products sold	1,100	892
Depreciation and amortization	378	360
Total operating costs	33,116	29,654
Earnings from operations	2,640	2,054
Interest expense	-150	-160
Earnings before income taxes	2,490	1,894
Provision for income taxes	-1,077	-795
Net earnings	$1,413	$1,099
Earnings per share:
Basic	$1.48	$1.12
Diluted	$1.46	$1.10
Basic weighted-average number of common shares outstanding	954	983
Dilutive effect of common share equivalents	15	13
Diluted weighted-average number of common shares outstanding	969	996
Anti-dilutive shares excluded from the calculation of dilutive effect of common share equivalents	9	9
Cash dividends declared per common share	$0.38	$0.28

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Net earnings	$1,413	$1,099
Other comprehensive (loss) income:
Gross unrealized gains on investment securities during the period	105	166
Income tax effect	-37	-61
Total unrealized gains, net of tax	68	105
Gross reclassification adjustment for net realized gains included in net earnings	-3	-46
Income tax effect	1	17
Total reclassification adjustment, net of tax	-2	-29
Total foreign currency translation (losses) gains	-959	259
Other comprehensive (loss) income	-893	335
Comprehensive income	$520	$1,434

Condesned_Consolidated_Stateme

Condesned Consolidated Statements of Changes in Shareholders' Equity (USD $)	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Net Unrealized Gains on Investments [Member]	Foreign Currency Translation (Losses) Gains
In Millions, unless otherwise specified
Balance at Dec. 31, 2013	$32,149	$10	$0	$33,047	$54	($962)
Balance (in shares) at Dec. 31, 2013		988
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	1,099			1,099
Other comprehensive income (loss)	335				76	259
Issuances of common share, and related tax effects (in shares)		8
Issuances of common share, and related tax effects	-6	0	-6
Share-based compensation, and related tax benefits	159		159
Common share repurchases (in shares)		-12
Common share repurchases	-911	0	-153	-758
Cash dividends paid on common shares	-276			-276
Balance at Mar. 31, 2014	32,549	10	0	33,112	130	-703
Balance (in shares) at Mar. 31, 2014		984
Balance at Dec. 31, 2014	32,454	10	0	33,836	223	-1,615
Balance (in shares) at Dec. 31, 2014	954	954
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	1,413			1,413
Other comprehensive income (loss)	-893				66	-959
Issuances of common share, and related tax effects (in shares)		6
Issuances of common share, and related tax effects	0	0	0
Share-based compensation, and related tax benefits	206		206
Noncontrolling interests fair value and other adjustments	-49		-49
Common share repurchases (in shares)		-8
Common share repurchases	-896	0	-157	-739
Cash dividends paid on common shares	-357			-357
Balance at Mar. 31, 2015	$31,878	$10	$0	$34,153	$289	($2,574)
Balance (in shares) at Mar. 31, 2015	952	952

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Operating activities
Net earnings	$1,413	$1,099
Noncash items:
Depreciation and amortization	378	360
Deferred income taxes	122	99
Share-based compensation	125	105
Other, net	-44	-65
Net change in other operating items, net of effects from acquisitions and changes in AARP balances:
Accounts receivable	-758	-990
Other assets	-2,162	-1,281
Medical costs payable	1,610	387
Accounts payable and other liabilities	1,648	1,665
Other policy liabilities	154	-203
Unearned revenues	-217	232
Cash flows from operating activities	2,269	1,408
Investing activities
Purchases of investments	-1,891	-2,914
Sales of investments	503	2,235
Maturities of investments	843	825
Cash paid for acquisitions, net of cash assumed	-575	-345
Purchases of property, equipment and capitalized software	-373	-353
Other, net	-32	-51
Cash flows used for investing activities	-1,525	-603
Financing activities
Common stock repurchases	-896	-911
Cash dividends paid	-357	-276
Proceeds from common stock issuances	192	216
Repayments of long-term debt	-416	-172
Proceeds from commercial paper, net	1,194	9
Customer funds administered	1,049	818
Other, net	-270	-257
Cash flows from (used for) financing activities	496	-573
Effect of exchange rate changes on cash and cash equivalents	-85	6
Increase in cash and cash equivalents	1,155	238
Cash and cash equivalents, beginning of period	7,495	7,276
Cash and Cash Equivalents, end of period	$8,650	$7,514

Basis_of_Presentation_Notes

Basis of Presentation (Notes)	3 Months Ended
	Mar. 31, 2015
Basis of Presentation and Significant Accounting Policies [Text Block]	UnitedHealth Group Incorporated (individually and together with its subsidiaries, “UnitedHealth Group” and “the Company”) is a diversified health and well-being company dedicated to helping people live healthier lives and making the health system work better for everyone. Through its diversified family of businesses, the Company leverages core competencies in advanced, enabling technology; health care data, information and intelligence; and clinical care management and coordination to help meet the demands of the health system. The Company offers a broad spectrum of products and services through two distinct platforms: UnitedHealthcare, which provides health care coverage and benefits services; and Optum, which provides information and technology-enabled health services.
	The Company has prepared the Condensed Consolidated Financial Statements according to U.S. Generally Accepted Accounting Principles (GAAP) and has included the accounts of UnitedHealth Group and its subsidiaries. The year-end condensed consolidated balance sheet was derived from audited financial statements, but does not include all disclosures required by GAAP. In accordance with the rules and regulations of the U.S. Securities and Exchange Commission (SEC), the Company has omitted certain footnote disclosures that would substantially duplicate the disclosures contained in its annual audited Consolidated Financial Statements. Therefore, these Condensed Consolidated Financial Statements should be read together with the Consolidated Financial Statements and the Notes included in Part II, Item 8, “Financial Statements” of the Company’s Annual Report on Form 10-K for the year ended December 31, 2014 as filed with the SEC (2014 10-K). The accompanying Condensed Consolidated Financial Statements include all normal recurring adjustments necessary to present the interim financial statements fairly.
	Use of Estimates
	These Condensed Consolidated Financial Statements include certain amounts based on the Company’s best estimates and judgments. The Company’s most significant estimates relate to estimates and judgments for medical costs payable and revenues, valuation and impairment analysis of goodwill and other intangible assets, estimates of other policy liabilities and other current receivables, valuations of certain investments, and estimates and judgments related to income taxes and contingent liabilities. Certain of these estimates require the application of complex assumptions and judgments, often because they involve matters that are inherently uncertain and will likely change in subsequent periods. The impact of any change in estimates is included in earnings in the period in which the estimate is adjusted.
	The accounting policies disclosed in Note 2 of Notes to the Consolidated Financial Statements in Part II, Item 8, “Financial Statements” in the 2014 10-K remain unchanged.
	Recently Issued Accounting Standards
	In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standard Update (ASU) No. 2014-09, “Revenue from Contracts with Customers (Topic 606)” (ASU 2014-09). ASU 2014-09 will supersede existing revenue recognition standards with a single model unless those contracts are within the scope of other standards (e.g., an insurance entity’s insurance contracts). The revenue recognition principle in ASU 2014-09 is that an entity should recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In addition, new and enhanced disclosures will be required. Companies can adopt the new standard either using the full retrospective approach, a modified retrospective approach with practical expedients, or a cumulative effect upon adoption approach. In April 2015, the FASB announced its intention to delay ASU 2014-09 for one year and is expected to become effective for annual and interim reporting periods beginning after December 15, 2017. Early adoption at the original effective date, interim and annual periods beginning after December 15, 2016, will be permitted. The Company is currently evaluating the effect of the new revenue recognition guidance.
	The Company has determined that there have been no other recently adopted or issued accounting standards that had, or will have, a material impact on its Condensed Consolidated Financial Statements.

Investments_Notes

Investments (Notes)	3 Months Ended
	Mar. 31, 2015
Investments [Abstract]
Investments [Text Block]	Investments
	A summary of short-term and long-term investments by major security type is as follows:
	(in millions)	Amortized			Gross			Gross			Fair
		Cost			Unrealized			Unrealized			Value
					Gains			Losses
	March 31, 2015
	Debt securities - available-for-sale:
	U.S. government and agency obligations	$	1,663		$	19		$	—		$	1,682
	State and municipal obligations	6,464			232			(3		)	6,693
	Corporate obligations	7,668			158			(10		)	7,816
	U.S. agency mortgage-backed securities	2,011			48			(3		)	2,056
	Non-U.S. agency mortgage-backed securities	858			16			(2		)	872
	Total debt securities - available-for-sale	18,664			473			(18		)	19,119
	Equity securities - available-for-sale	1,526			37			(33		)	1,530
	Debt securities - held-to-maturity:
	U.S. government and agency obligations	178			4			—			182
	State and municipal obligations	15			—			—			15
	Corporate obligations	354			—			—			354
	Total debt securities - held-to-maturity	547			4			—			551
	Total investments	$	20,737		$	514		$	(51	)	$	21,200
	December 31, 2014
	Debt securities - available-for-sale:
	U.S. government and agency obligations	$	1,614		$	7		$	(1	)	$	1,620
	State and municipal obligations	6,456			217			(5		)	6,668
	Corporate obligations	7,241			112			(26		)	7,327
	U.S. agency mortgage-backed securities	2,022			39			(5		)	2,056
	Non-U.S. agency mortgage-backed securities	872			12			(4		)	880
	Total debt securities - available-for-sale	18,205			387			(41		)	18,551
	Equity securities - available-for-sale	1,511			36			(25		)	1,522
	Debt securities - held-to-maturity:
	U.S. government and agency obligations	178			2			—			180
	State and municipal obligations	19			—			—			19
	Corporate obligations	298			—			—			298
	Total debt securities - held-to-maturity	495			2			—			497
	Total investments	$	20,211		$	425		$	(66	)	$	20,570
	The amortized cost and fair value of available-for-sale debt securities as of March 31, 2015, by contractual maturity, were as follows:
	(in millions)	Amortized			Fair
		Cost			Value
	Due in one year or less	$	1,856		$	1,862
	Due after one year through five years	6,927			7,035
	Due after five years through ten years	5,205			5,387
	Due after ten years	1,807			1,907
	U.S. agency mortgage-backed securities	2,011			2,056
	Non-U.S. agency mortgage-backed securities	858			872
	Total debt securities - available-for-sale	$	18,664		$	19,119
	The amortized cost and fair value of held-to-maturity debt securities as of March 31, 2015, by contractual maturity, were as follows:
	(in millions)	Amortized			Fair
		Cost			Value
	Due in one year or less	$	127		$	127
	Due after one year through five years	207			209
	Due after five years through ten years	109			110
	Due after ten years	104			105
	Total debt securities - held-to-maturity	$	547		$	551
	The fair value of available-for-sale investments with gross unrealized losses by major security type and length of time that individual securities have been in a continuous unrealized loss position were as follows:
		Less Than 12 Months						12 Months or Greater						Total
	(in millions)	Fair			Gross			Fair			Gross			Fair		Gross
		Value			Unrealized			Value			Unrealized			Value		Unrealized
					Losses						Losses					Losses
	March 31, 2015
	Debt securities - available-for-sale:
	State and municipal obligations	$	481		$	(2	)	$	27		$	(1	)	$	508	$	(3	)
	Corporate obligations	1,509			(7		)	235			(3		)	1,744		(10		)
	U.S. agency mortgage-backed securities	151			(1		)	133			(2		)	284		(3		)
	Non-U.S. agency mortgage-backed securities	186			(2		)	—			—			186		(2		)
Total debt securities - available-for-sale	$	2,327		$	(12	)	$	395		$	(6	)	$	2,722	$	(18	)
Equity securities - available-for-sale	$	76		$	(7	)	$	83		$	(26	)	$	159	$	(33	)
December 31, 2014
Debt securities - available-for-sale:
U.S. government and agency obligations	$	420		$	(1	)	$	—		$	—		$	420	$	(1	)
State and municipal obligations	711			(4		)	99			(1		)	810		(5		)
Corporate obligations	2,595			(17		)	464			(9		)	3,059		(26		)
U.S. agency mortgage-backed securities	—			—			272			(5		)	272		(5		)
Non-U.S. agency mortgage-backed securities	254			(2		)	114			(2		)	368		(4		)
Total debt securities - available-for-sale	$	3,980		$	(24	)	$	949		$	(17	)	$	4,929	$	(41	)
Equity securities - available-for-sale	$	107		$	(6	)	$	88		$	(19	)	$	195	$	(25	)
The Company’s unrealized losses from all securities as of March 31, 2015 were generated from approximately 4,000 positions out of a total of 23,000 positions. The Company believes that it will collect the principal and interest due on its debt securities that have an amortized cost in excess of fair value. The unrealized losses were primarily caused by interest rate increases and not by unfavorable changes in the credit quality associated with these securities. At each reporting period, the Company evaluates securities for impairment when the fair value of the investment is less than its amortized cost. The Company evaluated the underlying credit quality and credit ratings of the issuers, noting neither a significant deterioration since purchase nor other factors leading to an other-than-temporary impairment (OTTI). As of March 31, 2015, the Company did not have the intent to sell any of the securities in an unrealized loss position. Therefore, the Company believes these losses to be temporary.
The Company’s investments in equity securities consist of investments in Brazilian real denominated fixed-income funds, employee savings plan related investments, venture capital funds, and dividend paying stocks. The Company evaluated its investments in equity securities for severity and duration of unrealized loss, overall market volatility and other market factors.
Net realized gains reclassified out of accumulated other comprehensive income were from the following sources:
	Three Months Ended March 31,
(in millions)	2015			2014
Total OTTI	$	(1	)	$	(3	)
Portion of loss recognized in other comprehensive income	—			—
Net OTTI recognized in earnings	(1		)	(3		)
Gross realized losses from sales	(6		)	(10		)
Gross realized gains from sales	10			59
Net realized gains (included in investment and other income on the Condensed Consolidated Statements of Operations)	3			46
Income tax effect (included in provision for income taxes on the Condensed Consolidated Statements of Operations)	(1		)	(17		)
Realized gains, net of taxes	$	2		$	29

Fair_Value_Notes

Fair Value (Notes)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value [Text Block]	Fair Value
	Certain assets and liabilities are measured at fair value in the Condensed Consolidated Financial Statements or have fair values disclosed in the Notes to the Condensed Consolidated Financial Statements. These assets and liabilities are classified into one of three levels of a hierarchy defined by GAAP.
	For a description of the methods and assumptions that are used to estimate the fair value and determine the fair value hierarchy classification of each class of financial instrument, see Note 4 of Notes to the Consolidated Financial Statements in Part II, Item 8, “Financial Statements” in the 2014 10-K.
	The following table presents a summary of fair value measurements by level and carrying values for items measured at fair value on a recurring basis in the Condensed Consolidated Balance Sheets excluding assets and liabilities, related to a Supplemental Health Insurance Program (AARP Program), which are presented in a separate table below:
	(in millions)	Quoted Prices			Other			Unobservable			Total
		in Active			Observable			Inputs			Fair and Carrying
		Markets			Inputs			(Level 3)			Value
		(Level 1)			(Level 2)
	March 31, 2015
	Cash and cash equivalents	$	8,617		$	33		$	—		$	8,650
	Debt securities - available-for-sale:
	U.S. government and agency obligations	1,466			216			—			1,682
	State and municipal obligations	—			6,693			—			6,693
	Corporate obligations	7			7,736			73			7,816
	U.S. agency mortgage-backed securities	—			2,056			—			2,056
	Non-U.S. agency mortgage-backed securities	—			866			6			872
	Total debt securities - available-for-sale	1,473			17,567			79			19,119
	Equity securities - available-for-sale	1,209			12			309			1,530
	Interest rate swap assets	—			230			—			230
	Total assets at fair value	$	11,299		$	17,842		$	388		$	29,529
	Percentage of total assets at fair value	38		%	61		%	1		%	100		%
	Interest rate swap liabilities	$	—		$	1		$	—		$	1
	December 31, 2014
	Cash and cash equivalents	$	7,472		$	23		$	—		$	7,495
	Debt securities - available-for-sale:
	U.S. government and agency obligations	1,427			193			—			1,620
	State and municipal obligations	—			6,668			—			6,668
	Corporate obligations	2			7,257			68			7,327
	U.S. agency mortgage-backed securities	—			2,056			—			2,056
	Non-U.S. agency mortgage-backed securities	—			874			6			880
	Total debt securities - available-for-sale	1,429			17,048			74			18,551
	Equity securities - available-for-sale	1,200			12			310			1,522
	Interest rate swap assets	—			62			—			62
	Total assets at fair value	$	10,101		$	17,145		$	384		$	27,630
	Percentage of total assets at fair value	37		%	62		%	1		%	100		%
	Interest rate swap liabilities	$	—		$	55		$	—		$	55
	Transfers between levels, if any, are recorded as of the beginning of the reporting period in which the transfer occurs; there were no transfers between Levels 1, 2 or 3 of any financial assets or liabilities during the three months ended March 31, 2015 or 2014.
	The following table presents a summary of fair value measurements by level and carrying values for certain financial instruments not measured at fair value on a recurring basis in the Condensed Consolidated Balance Sheets:
	(in millions)	Quoted Prices			Other			Unobservable			Total			Total Carrying Value
		in Active			Observable			Inputs			Fair
		Markets			Inputs			(Level 3)			Value
		(Level 1)			(Level 2)
	March 31, 2015
	Debt securities - held-to-maturity:
	U.S. government and agency obligations	$	182		$	—		$	—		$	182		$	178
	State and municipal obligations	—			—			15			15			15
	Corporate obligations	93			10			251			354			354
	Total debt securities - held-to-maturity	$	275		$	10		$	266		$	551		$	547
	Other assets	$	—		$	490		$	—		$	490		$	489
	Long-term debt and other financing obligations	$	—		$	18,826		$	—		$	18,826		$	16,859
	December 31, 2014
	Debt securities - held-to-maturity:
	U.S. government and agency obligations	$	180		$	—		$	—		$	180		$	178
	State and municipal obligations	—			—			19			19			19
	Corporate obligations	46			10			242			298			298
	Total debt securities - held-to-maturity	$	226		$	10		$	261		$	497		$	495
	Other assets	$	—		$	478		$	—		$	478		$	484
	Long-term debt and other financing obligations	$	—		$	18,863		$	—		$	18,863		$	17,085
	Nonfinancial assets and liabilities or financial assets and liabilities that are measured at fair value on a nonrecurring basis are subject to fair value adjustments only in certain circumstances, such as when the Company records an impairment. There were no significant fair value adjustments for these assets and liabilities recorded during the three months ended March 31, 2015 or 2014.
	The carrying amounts reported on the Condensed Consolidated Balance Sheets for other current financial assets and liabilities approximate fair value because of their short-term nature. These assets and liabilities are not listed in the table above.
	A reconciliation of the beginning and ending balances of assets measured at fair value on a recurring basis using Level 3 inputs is as follows:
		31-Mar-15									31-Mar-14
	(in millions)	Debt			Equity			Total			Debt			Equity			Total
		Securities			Securities						Securities			Securities
Balance at beginning of period	$	74		$	310		$	384		$	42		$	269		$	311
Purchases	4			4			8			3			44			47
Sales	—			(1		)	(1		)	—			(4		)	(4		)
Net unrealized gains (losses) in accumulated other comprehensive income	1			(5		)	(4		)	1			4			5
Net realized gains in investment and other income	—			1			1			—			—			—
Balance at end of period	$	79		$	309		$	388		$	46		$	313		$	359
The following table presents quantitative information regarding unobservable inputs that were significant to the valuation of assets measured at fair value on a recurring basis using Level 3 inputs:
							Range
(in millions)	Fair Value			Valuation Technique		Unobservable Input	Low		High
March 31, 2015
Equity securities - available-for-sale
Venture capital portfolios	$	259		Market approach - comparable companies		Revenue multiple	1		7
						EBITDA multiple	8		10
	50			Market approach - recent transactions		Inactive market transactions	N/A		N/A
Total equity securities	$	309
available-for-sale
Also included in the Company’s assets measured at fair value on a recurring basis using Level 3 inputs were $79 million of available-for-sale debt securities as of March 31, 2015, which were not significant.
The Company elected to measure the entirety of the AARP Program assets under management at fair value pursuant to the fair value option. See Note 2 of Notes to the Consolidated Financial Statements in Part II, Item 8, “Financial Statements” in the Company’s 2014 10-K for further detail on the AARP Program. The following table presents fair value information about the AARP Program-related financial assets and liabilities:
(in millions)	Quoted Prices			Other			Total
	in Active			Observable			Fair and Carrying
	Markets			Inputs			Value
	(Level 1)			(Level 2)
March 31, 2015
Cash and cash equivalents	$	262		$	—		$	262
Debt securities:
U.S. government and agency obligations	407			214			621
State and municipal obligations	—			96			96
Corporate obligations	—			1,279			1,279
U.S. agency mortgage-backed securities	—			375			375
Non-U.S. agency mortgage-backed securities	—			203			203
Total debt securities	407			2,167			2,574
Other investments	—			85			85
Total assets at fair value	$	669		$	2,252		$	2,921
Other liabilities	$	8		$	24		$	32
December 31, 2014
Cash and cash equivalents	$	415		$	—		$	415
Debt securities:
U.S. government and agency obligations	409			245			654
State and municipal obligations	—			95			95
Corporate obligations	—			1,200			1,200
U.S. agency mortgage-backed securities	—			340			340
Non-U.S. agency mortgage-backed securities	—			177			177
Total debt securities	409			2,057			2,466
Other investments	—			81			81
Total assets at fair value	$	824		$	2,138		$	2,962
Other liabilities	$	5		$	13		$	18

Medicare_Part_D_Pharmacy_Benef

Medicare Part D Pharmacy Benefits (Notes)	3 Months Ended
	Mar. 31, 2015
Condensed Balance Sheet Statements, Captions [Line Items]
Medicare Part D Pharmacy Benefits Contract [Text Block]	Medicare Part D Pharmacy Benefits
	The Condensed Consolidated Balance Sheets include the following amounts associated with the Medicare Part D program:
		March 31, 2015						December 31, 2014
	(in millions)	Subsidies		Drug Discount		Risk-Share		Subsidies		Drug Discount		Risk-Share
	Other current receivables	$	1,448	$	239	$	46	$	1,801	$	719	$	20
	Other policy liabilities	—		—		—		—		302		—
	As of March 31, 2015, the Centers for Medicare and Medicaid Services (CMS) had underfunded the payment for drug discounts and accordingly, the Company recorded a receivable from CMS along with the receivables from pharmaceutical manufacturers. See Note 2 of Notes to the Consolidated Financial Statements in Part II, Item 8, “Financial Statements” in the Company’s 2014 10-K for further detail on Medicare Part D.

Medical_Costs_Reserve_Developm

Medical Costs Reserve Development (Notes)	3 Months Ended
	Mar. 31, 2015
Medical Cost Development Disclosure Text Block	Medical Costs Reserve Development
	Favorable medical cost reserve development was $140 million and $220 million for the three months ended March 31, 2015 and 2014, respectively. In both periods, favorable development was driven by a number of individual factors that were not material.

Health_Insurance_Industry_Tax_

Health Insurance Industry Tax (Notes)	3 Months Ended
	Mar. 31, 2015
Industry Tax [Line Items]
Health Insurance Industry Tax [Text Block]	Health Insurance Industry Tax
	The Patient Protection and Affordable Care Act and a reconciliation measure, the Health Care and Education Reconciliation Act of 2010 (together, Health Reform Legislation) includes an annual, nondeductible insurance industry tax (Health Insurance Industry Tax). As of March 31, 2015, the liability recorded in accounts payable and accrued liabilities related to the Health Insurance Industry Tax was $1.8 billion. The corresponding deferred cost recorded in prepaid expenses and other current assets on the Condensed Consolidated Balance Sheets was $1.4 billion. There was no liability or asset related to the Health Insurance Industry Tax recorded as of December 31, 2014 as the Health Insurance Industry Tax was paid in September 2014. See Note 2 of Notes to the Consolidated Financial Statements in Part II, Item 8, “Financial Statements” in the Company’s 2014 10-K for further detail on the Health Insurance Industry Tax.

Commercial_Paper_and_LongTerm_

Commercial Paper and Long-Term Debt (Notes)	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Commercial Paper and Long-Term Debt [Text Block]	Commercial Paper and Long-Term Debt
	Commercial paper and senior unsecured long-term debt consisted of the following:
			March 31, 2015								December 31, 2014
	(in millions, except percentages)		Par			Carrying			Fair		Par		Carrying		Fair
			Value			Value			Value		Value		Value		Value
	Commercial paper		$	1,515		$	1,515		$	1,515	$	321	$	321	$	321
	4.875% notes due March 2015 (a)		—			—			—		416		419		419
	0.850% notes due October 2015 (a)		625			626			626		625		625		627
	5.375% notes due March 2016 (a)		601			620			627		601		623		634
	1.875% notes due November 2016 (a)		400			400			407		400		397		406
	5.360% notes due November 2016		95			95			102		95		95		103
	6.000% notes due June 2017 (a)		441			467			488		441		466		489
	1.400% notes due October 2017 (a)		625			624			631		625		616		624
	6.000% notes due November 2017 (a)		156			165			175		156		164		175
	1.400% notes due December 2017 (a)		750			755			756		750		745		749
	6.000% notes due February 2018 (a)		1,100			1,120			1,245		1,100		1,106		1,238
	1.625% notes due March 2019 (a)		500			506			501		500		496		493
	2.300% notes due December 2019 (a)		500			508			510		500		496		502
	3.875% notes due October 2020 (a)		450			463			492		450		450		477
	4.700% notes due February 2021 (a)		400			424			456		400		413		450
	3.375% notes due November 2021 (a)		500			512			534		500		496		519
	2.875% notes due December 2021 (a)		750			773			770		750		748		759
	2.875% notes due March 2022 (a)		1,100			1,082			1,119		1,100		1,042		1,104
	0.000% notes due November 2022		15			10			11		15		10		11
	2.750% notes due February 2023 (a)		625			628			631		625		604		613
	2.875% notes due March 2023 (a)		750			806			768		750		777		745
	5.800% notes due March 2036		850			845			1,096		850		845		1,052
	6.500% notes due June 2037		500			495			703		500		495		670
	6.625% notes due November 2037		650			646			927		650		646		888
	6.875% notes due February 2038		1,100			1,085			1,584		1,100		1,085		1,544
	5.700% notes due October 2040		300			298			387		300		298		378
	5.950% notes due February 2041		350			348			471		350		348		455
	4.625% notes due November 2041		600			593			677		600		593		646
	4.375% notes due March 2042		502			486			553		502		486		536
	3.950% notes due October 2042		625			611			640		625		611		621
	4.250% notes due March 2043		750			740			811		750		740		786
	Total commercial paper and long-term debt		$	18,125		$	18,246		$	20,213	$	17,347	$	17,256	$	19,034
	(a)	Fixed-rate debt instruments hedged with interest rate swap contracts. See below for more information on the Company’s interest rate swaps.
	The Company’s long-term debt obligations also included $128 million and $150 million of other financing obligations, of which $36 million and $34 million were current as of March 31, 2015 and December 31, 2014, respectively.
	Commercial Paper and Bank Credit Facilities
	Commercial paper consists of short-duration, senior unsecured debt privately placed on a discount basis through broker-dealers. As of March 31, 2015, the Company’s outstanding commercial paper had a weighted-average annual interest rate of 0.3%.
	The Company has $3.0 billion five-year and $1.0 billion 364-day revolving bank credit facilities with 23 banks, which mature in November 2019 and November 2015, respectively. These facilities provide liquidity support for the Company’s commercial paper program and are available for general corporate purposes. There were no amounts outstanding under these facilities as of March 31, 2015. The interest rates on borrowings are variable based on term and are calculated based on the London Interbank Offered Rate (LIBOR) plus a credit spread based on the Company’s senior unsecured credit ratings. As of March 31, 2015, the annual interest rates on the bank credit facilities, had they been drawn, would have ranged from 1.0% to 1.2%.
	On May 1, 2015, the Company entered into an additional $2.0 billion 364-day revolving bank credit facility to provide liquidity support for the Company’s commercial paper program. In addition, on the same date, the Company entered into a $1.5 billion delayed draw term loan. The commercial paper and term loan proceeds will be used to fund a portion of the purchase of Catamaran Corporation (Catamaran). No amounts have been drawn on the $2.0 billion bank credit facility or the $1.5 billion term loan. For more information on the purchase of Catamaran, see Note 9.
	Debt Covenants
	The Company’s bank credit facilities contain various covenants including requiring the Company to maintain a debt to debt-plus-equity ratio of not more than 50%. The Company was in compliance with its debt covenants as of March 31, 2015.
	Interest Rate Swap Contracts
	The Company uses interest rate swap contracts to convert a portion of its interest rate exposure from fixed rates to floating rates to more closely align interest expense with interest income received on its variable rate financial assets. The floating rates are benchmarked to LIBOR. The swaps are designated as fair value hedges on the Company’s fixed-rate debt. Since the critical terms of the swaps match those of the debt being hedged, they are considered to be highly effective hedges and all changes in the fair values of the swaps are recorded as adjustments to the carrying value of the related debt with no net impact recorded on the Condensed Consolidated Statements of Operations. Both the hedge fair value changes and the offsetting debt adjustments are recorded in interest expense on the Condensed Consolidated Statements of Operations. The following table summarizes the location and fair value of the interest rate swap fair value hedges on the Company’s Condensed Consolidated Balance Sheet:
	Type of Fair Value Hedge		Notional Amount			Fair Value			Balance Sheet Location
			(in billions)			(in millions)
	March 31, 2015
	Interest rate swap contracts		$	10.3		$	2		Prepaid expenses and other current assets
						228			Other assets
						1			Other liabilities
	31-Dec-14
	Interest rate swap contracts		$	10.7		$	62		Other assets
						55			Other liabilities
	The following table provides a summary of the effect of changes in fair value of fair value hedges on the Company’s Condensed Consolidated Statements of Operations:
			Three Months Ended March 31,
	(in millions)		2015			2014
	Hedge - interest rate swap gain recognized in interest expense		$	222		$	66
	Hedged item - long-term debt loss recognized in interest expense		(222		)	(66		)
	Net impact on the Company’s Condensed Consolidated Statements of Operations		$	—		$	—

ShareBased_Compensation_Notes

Share-Based Compensation (Notes)	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]	Share-Based Compensation
	The Company’s outstanding share-based awards consist mainly of nonqualified stock options, stock-settled stock appreciation rights (SARs) and restricted stock and restricted stock units (collectively, restricted shares).
	Stock Options and SARs
	Stock option and SAR activity for the three months ended March 31, 2015 is summarized in the table below:
		Shares			Weighted-				Weighted-	Aggregate
					Average				Average	Intrinsic Value
					Exercise				Remaining
					Price				Contractual Life
		(in millions)							(in years)	(in millions)
	Outstanding at beginning of period	33			$	53
	Granted	8			109
	Exercised	(4	)		52
	Outstanding at end of period	37			66				6.3	$	1,959
	Exercisable at end of period	19			47				3.8	1,368
	Vested and expected to vest, end of period	36			65				6.2	1,920
	Restricted Shares
	Restricted share activity for the three months ended March 31, 2015 is summarized in the table below:
	(shares in millions)		Shares			Weighted-Average
						Grant Date
						Fair Value
						per Share
	Nonvested at beginning of period		9			$	61
	Granted		2			109
	Vested		(4	)		57
	Nonvested at end of period		7			78
	Other Share-Based Compensation Data
	(in millions, except per share amounts)		Three Months Ended
			March 31,
			2015				2014
	Stock Options and SARs
	Weighted-average grant date fair value of shares granted, per share		$	23			$	22
	Total intrinsic value of stock options and SARs exercised		221				212
	Restricted Shares
	Weighted-average grant date fair value of shares granted, per share		109				70
	Total fair value of restricted shares vested		395				414
	Share-Based Compensation Items
	Share-based compensation expense, before tax		125				105
	Share-based compensation expense, net of tax effects		101				86
	Income tax benefit realized from share-based award exercises		138				119
	(in millions, except years)		March 31, 2015
	Unrecognized compensation expense related to share awards		$	618
	Weighted-average years to recognize compensation expense		1.1
	Share-Based Compensation Recognition and Estimates
	The principal assumptions the Company used in calculating grant-date fair value for stock options and SARs were as follows:
			Three Months Ended March 31,
			2015		2014
	Risk-free interest rate		1.60%		1.70%
	Expected volatility		24.10%		39.60%
	Expected dividend yield		1.40%		1.60%
	Forfeiture rate		5.00%		5.00%
	Expected life in years		6.1		5.4

Commitments_and_Contingencies_

Commitments and Contingencies (Notes)	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies Disclosure [Text Block]	Commitments and Contingencies
	Pending Acquisition
	In March 2015, the Company entered into an agreement to acquire Catamaran. Catamaran offers retail pharmacy network management, mail service pharmacy, pharmacy claims management and patient-centric specialty pharmacy services to a broad client portfolio, including health plans and employers, serving 35 million people and provides health care information technology solutions to the pharmacy benefits management industry. The Company will acquire for $12.8 billion in cash all of Catamaran’s outstanding common stock and assume Catamaran’s outstanding debt, net of acquired cash. The transaction is expected to close during the fourth quarter of 2015, subject to Catamaran shareholder approval, regulatory approvals and other customary closing conditions.
	Legal Matters
	Because of the nature of its businesses, the Company is frequently made party to a variety of legal actions and regulatory inquiries, including class actions and suits brought by members, care providers, consumer advocacy organizations, customers and regulators, relating to the Company’s businesses, including management and administration of health benefit plans and other services. These matters include medical malpractice, employment, intellectual property, antitrust, privacy and contract claims, and claims related to health care benefits coverage and other business practices.
	The Company records liabilities for its estimates of probable costs resulting from these matters where appropriate. Estimates of costs resulting from legal and regulatory matters involving the Company are inherently difficult to predict, particularly where the matters: involve indeterminate claims for monetary damages or may involve fines, penalties or punitive damages; present novel legal theories or represent a shift in regulatory policy; involve a large number of claimants or regulatory bodies; are in the early stages of the proceedings; or could result in a change in business practices. Accordingly, the Company is often unable to estimate the losses or ranges of losses for those matters where there is a reasonable possibility or it is probable that a loss may be incurred.
	Litigation Matters
	California Claims Processing Matter. On January 25, 2008, the California Department of Insurance (CDI) issued an Order to Show Cause to PacifiCare Life and Health Insurance Company, a subsidiary of the Company, alleging violations of certain insurance statutes and regulations related to an alleged failure to include certain language in standard claims correspondence, timeliness and accuracy of claims processing, interest payments, care provider contract implementation, care provider dispute resolution and other related matters. Although the Company believes that CDI had never before issued a fine in excess of $8 million, CDI advocated a fine of approximately $325 million in this matter. The matter was the subject of an administrative hearing before a California administrative law judge beginning in December 2009, and in August 2013, the administrative law judge issued a nonbinding proposed decision recommending a fine of $11.5 million. The California Insurance Commissioner rejected the administrative law judge’s recommendation and on June 9, 2014, issued his own decision imposing a fine of approximately $174 million. On July 10, 2014, the Company filed a lawsuit in California state court challenging the Commissioner’s decision. The Company cannot reasonably estimate the range of loss, if any, that may result from this matter given the procedural status of the dispute, the wide range of possible outcomes, the legal issues presented (including the legal basis for the majority of the alleged violations), the inherent difficulty in predicting a regulatory fine in the event of a remand, and the various remedies and levels of judicial review that remain available to the Company.
	Government Investigations, Audits and Reviews
	The Company has been involved or is currently involved in various governmental investigations, audits and reviews. These include routine, regular and special investigations, audits and reviews by CMS, state insurance and health and welfare departments, the Brazilian national regulatory agency for private health insurance and plans (the Agência Nacional de Saúde Suplementar), state attorneys general, the Office of the Inspector General, the Office of Personnel Management, the Office of Civil Rights, the Government Accountability Office, the Federal Trade Commission, U.S. Congressional committees, the U.S. Department of Justice, the SEC, the Internal Revenue Service, the Brazilian federal revenue service (the Secretaria da Receita Federal), the U.S. Department of Labor, the Federal Deposit Insurance Corporation, the Defense Contract Audit Agency and other governmental authorities. Certain of the Company’s businesses have been reviewed or are currently under review, including for, among other things, compliance with coding and other requirements under the Medicare risk-adjustment model.
	In February 2012, CMS announced a final Risk Adjustment Data Validation (RADV) audit and payment adjustment methodology and that it will conduct RADV audits beginning with the 2011 payment year. These audits involve a review of medical records maintained by care providers and may result in retrospective adjustments to payments made to health plans. CMS has not communicated how the final payment adjustment under its methodology will be implemented.
	The Company cannot reasonably estimate the range of loss, if any, that may result from any material government investigations, audits and reviews in which it is currently involved given the inherent difficulty in predicting regulatory action, fines and penalties, if any, and the various remedies and levels of judicial review available to the Company in the event of an adverse finding.
	Guaranty Fund Assessments
	Under state guaranty fund laws, certain insurance companies can be assessed (up to prescribed limits) for certain obligations to the policyholders and claimants of insolvent insurance companies. In 2009, the Pennsylvania Insurance Commissioner placed long term care insurer Penn Treaty Network America Insurance Company and its subsidiary (Penn Treaty), neither of which is affiliated with the Company, in rehabilitation and petitioned a state court for approval to liquidate Penn Treaty. In 2012, the court denied the liquidation petition and ordered the Insurance Commissioner to submit a rehabilitation plan. In December 2014, the court set a hearing for July 2015 to consider the latest proposed rehabilitation plan.
	If the current proposed rehabilitation plan, which contemplates the partial liquidation of Penn Treaty, is approved by the court, the Company’s insurance entities and other insurers may be required to pay a portion of Penn Treaty’s policyholder claims through state guaranty association assessments in future periods. The Company intends to vigorously challenge the proposed rehabilitation plan. The Company is currently unable to estimate losses or ranges of losses because the Company cannot predict whether, when or to what extent Penn Treaty will ultimately be declared insolvent, the amount of the insolvency, if any, the amount and timing of any associated guaranty fund assessments or the availability and amount of any premium tax and other potential offsets.

Segment_Financial_Information_

Segment Financial Information (Notes)	3 Months Ended
	Mar. 31, 2015
Segment Reporting [Abstract]
Segment Financial Information [Text Block]	Segment Financial Information
	The Company’s four reportable segments are UnitedHealthcare, OptumHealth, OptumInsight and OptumRx. For more information on the Company’s segments see Part I, Item I, “Business” and Note 13 of Notes to the Consolidated Financial Statements in Part II, Item 8, “Financial Statements” in the Company's 2014 10-K.
	The following table presents the reportable segment financial information:
				Optum
	(in millions)	UnitedHealthcare		OptumHealth		OptumInsight		OptumRx		Optum Eliminations			Optum		Corporate and			Consolidated
															Eliminations
	Three Months Ended
	March 31, 2015
	Revenues - external customers:
	Premiums	$	30,905	$	769	$	—	$	—	$	—		$	769	$	—		$	31,674
	Services	1,603		521		559		23		—			1,103		—			2,706
	Products	—		5		20		1,205		—			1,230		—			1,230
	Total revenues - external customers	32,508		1,295		579		1,228		—			3,102		—			35,610
	Total revenues - intersegment	—		1,963		811		7,067		(159		)	9,682		(9,682		)	—
	Investment and other income	115		31		—		—		—			31		—			146
	Total revenues	$	32,623	$	3,289	$	1,390	$	8,295	$	(159	)	$	12,815	$	(9,682	)	$	35,756
	Earnings from operations	$	1,898	$	234	$	222	$	286	$	—		$	742	$	—		$	2,640
	Interest expense	—		—		—		—		—			—		(150		)	(150		)
	Earnings before income taxes	$	1,898	$	234	$	222	$	286	$	—		$	742	$	(150	)	$	2,490
	Three Months Ended
	31-Mar-14
	Revenues - external customers:
	Premiums	$	27,511	$	604	$	—	$	—	$	—		$	604	$	—		$	28,115
	Services	1,586		263		525		30		—			818		—			2,404
	Products	1		7		26		964		—			997		—			998
	Total revenues - external customers	29,098		874		551		994		—			2,419		—			31,517
	Total revenues - intersegment	—		1,671		696		6,464		(115		)	8,716		(8,716		)	—
	Investment and other income	156		35		—		—		—			35		—			191
	Total revenues	$	29,254	$	2,580	$	1,247	$	7,458	$	(115	)	$	11,170	$	(8,716	)	$	31,708
	Earnings from operations	$	1,404	$	211	$	197	$	242	$	—		$	650	$	—		$	2,054
	Interest expense	—		—		—		—		—			—		(160		)	(160		)
	Earnings before income taxes	$	1,404	$	211	$	197	$	242	$	—		$	650	$	(160	)	$	1,894

Basis_of_Presentation_Policies

Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2015
Basis of presentation [Abstract]
Basis of Accounting, Policy [Policy Text Block]	The Company has prepared the Condensed Consolidated Financial Statements according to U.S. Generally Accepted Accounting Principles (GAAP) and has included the accounts of UnitedHealth Group and its subsidiaries. The year-end condensed consolidated balance sheet was derived from audited financial statements, but does not include all disclosures required by GAAP. In accordance with the rules and regulations of the U.S. Securities and Exchange Commission (SEC), the Company has omitted certain footnote disclosures that would substantially duplicate the disclosures contained in its annual audited Consolidated Financial Statements. Therefore, these Condensed Consolidated Financial Statements should be read together with the Consolidated Financial Statements and the Notes included in Part II, Item 8, “Financial Statements” of the Company’s Annual Report on Form 10-K for the year ended December 31, 2014 as filed with the SEC (2014 10-K). The accompanying Condensed Consolidated Financial Statements include all normal recurring adjustments necessary to present the interim financial statements fairly.
Use of Estimates, Policy [Policy Text Block]	Use of Estimates
	These Condensed Consolidated Financial Statements include certain amounts based on the Company’s best estimates and judgments. The Company’s most significant estimates relate to estimates and judgments for medical costs payable and revenues, valuation and impairment analysis of goodwill and other intangible assets, estimates of other policy liabilities and other current receivables, valuations of certain investments, and estimates and judgments related to income taxes and contingent liabilities. Certain of these estimates require the application of complex assumptions and judgments, often because they involve matters that are inherently uncertain and will likely change in subsequent periods. The impact of any change in estimates is included in earnings in the period in which the estimate is adjusted.
New Accounting Pronouncements, Policy [Policy Text Block]	In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standard Update (ASU) No. 2014-09, “Revenue from Contracts with Customers (Topic 606)” (ASU 2014-09). ASU 2014-09 will supersede existing revenue recognition standards with a single model unless those contracts are within the scope of other standards (e.g., an insurance entity’s insurance contracts). The revenue recognition principle in ASU 2014-09 is that an entity should recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In addition, new and enhanced disclosures will be required. Companies can adopt the new standard either using the full retrospective approach, a modified retrospective approach with practical expedients, or a cumulative effect upon adoption approach. In April 2015, the FASB announced its intention to delay ASU 2014-09 for one year and is expected to become effective for annual and interim reporting periods beginning after December 15, 2017. Early adoption at the original effective date, interim and annual periods beginning after December 15, 2016, will be permitted. The Company is currently evaluating the effect of the new revenue recognition guidance.

Investments_Tables

Investments (Tables)	3 Months Ended
	Mar. 31, 2015
Short-Term and Long-Term Investments [Table Text Block]	A summary of short-term and long-term investments by major security type is as follows:
	(in millions)	Amortized			Gross			Gross			Fair
		Cost			Unrealized			Unrealized			Value
					Gains			Losses
	March 31, 2015
	Debt securities - available-for-sale:
	U.S. government and agency obligations	$	1,663		$	19		$	—		$	1,682
	State and municipal obligations	6,464			232			(3		)	6,693
	Corporate obligations	7,668			158			(10		)	7,816
	U.S. agency mortgage-backed securities	2,011			48			(3		)	2,056
	Non-U.S. agency mortgage-backed securities	858			16			(2		)	872
	Total debt securities - available-for-sale	18,664			473			(18		)	19,119
	Equity securities - available-for-sale	1,526			37			(33		)	1,530
	Debt securities - held-to-maturity:
	U.S. government and agency obligations	178			4			—			182
	State and municipal obligations	15			—			—			15
	Corporate obligations	354			—			—			354
	Total debt securities - held-to-maturity	547			4			—			551
	Total investments	$	20,737		$	514		$	(51	)	$	21,200
	December 31, 2014
	Debt securities - available-for-sale:
	U.S. government and agency obligations	$	1,614		$	7		$	(1	)	$	1,620
	State and municipal obligations	6,456			217			(5		)	6,668
	Corporate obligations	7,241			112			(26		)	7,327
	U.S. agency mortgage-backed securities	2,022			39			(5		)	2,056
	Non-U.S. agency mortgage-backed securities	872			12			(4		)	880
	Total debt securities - available-for-sale	18,205			387			(41		)	18,551
	Equity securities - available-for-sale	1,511			36			(25		)	1,522
	Debt securities - held-to-maturity:
	U.S. government and agency obligations	178			2			—			180
	State and municipal obligations	19			—			—			19
	Corporate obligations	298			—			—			298
	Total debt securities - held-to-maturity	495			2			—			497
	Total investments	$	20,211		$	425		$	(66	)	$	20,570
Fair Value of Available-for-Sale Investments with Gross Unrealized Losses by Investment Type and Length of Time that Individual Securities have been in a Continuous Unrealized Loss Position [Table Text Block]	The fair value of available-for-sale investments with gross unrealized losses by major security type and length of time that individual securities have been in a continuous unrealized loss position were as follows:
		Less Than 12 Months						12 Months or Greater						Total
	(in millions)	Fair			Gross			Fair			Gross			Fair		Gross
		Value			Unrealized			Value			Unrealized			Value		Unrealized
					Losses						Losses					Losses
	March 31, 2015
	Debt securities - available-for-sale:
	State and municipal obligations	$	481		$	(2	)	$	27		$	(1	)	$	508	$	(3	)
	Corporate obligations	1,509			(7		)	235			(3		)	1,744		(10		)
	U.S. agency mortgage-backed securities	151			(1		)	133			(2		)	284		(3		)
	Non-U.S. agency mortgage-backed securities	186			(2		)	—			—			186		(2		)
	Total debt securities - available-for-sale	$	2,327		$	(12	)	$	395		$	(6	)	$	2,722	$	(18	)
	Equity securities - available-for-sale	$	76		$	(7	)	$	83		$	(26	)	$	159	$	(33	)
	December 31, 2014
	Debt securities - available-for-sale:
	U.S. government and agency obligations	$	420		$	(1	)	$	—		$	—		$	420	$	(1	)
	State and municipal obligations	711			(4		)	99			(1		)	810		(5		)
	Corporate obligations	2,595			(17		)	464			(9		)	3,059		(26		)
	U.S. agency mortgage-backed securities	—			—			272			(5		)	272		(5		)
	Non-U.S. agency mortgage-backed securities	254			(2		)	114			(2		)	368		(4		)
	Total debt securities - available-for-sale	$	3,980		$	(24	)	$	949		$	(17	)	$	4,929	$	(41	)
	Equity securities - available-for-sale	$	107		$	(6	)	$	88		$	(19	)	$	195	$	(25	)
Net Realized Gains, Included in Investment and Other Income [Table Text Block]	Net realized gains reclassified out of accumulated other comprehensive income were from the following sources:
		Three Months Ended March 31,
	(in millions)	2015			2014
	Total OTTI	$	(1	)	$	(3	)
	Portion of loss recognized in other comprehensive income	—			—
	Net OTTI recognized in earnings	(1		)	(3		)
	Gross realized losses from sales	(6		)	(10		)
	Gross realized gains from sales	10			59
	Net realized gains (included in investment and other income on the Condensed Consolidated Statements of Operations)	3			46
	Income tax effect (included in provision for income taxes on the Condensed Consolidated Statements of Operations)	(1		)	(17		)
	Realized gains, net of taxes	$	2		$	29
Available-for-sale Securities [Member]
Investments by Contractual Maturity [Table Text Block]	The amortized cost and fair value of available-for-sale debt securities as of March 31, 2015, by contractual maturity, were as follows:
	(in millions)	Amortized			Fair
		Cost			Value
	Due in one year or less	$	1,856		$	1,862
	Due after one year through five years	6,927			7,035
	Due after five years through ten years	5,205			5,387
	Due after ten years	1,807			1,907
	U.S. agency mortgage-backed securities	2,011			2,056
	Non-U.S. agency mortgage-backed securities	858			872
	Total debt securities - available-for-sale	$	18,664		$	19,119
Held-to-maturity Securities [Member]
Investments by Contractual Maturity [Table Text Block]	The amortized cost and fair value of held-to-maturity debt securities as of March 31, 2015, by contractual maturity, were as follows:
	(in millions)	Amortized			Fair
		Cost			Value
	Due in one year or less	$	127		$	127
	Due after one year through five years	207			209
	Due after five years through ten years	109			110
	Due after ten years	104			105
	Total debt securities - held-to-maturity	$	547		$	551

Fair_Value_Tables

Fair Value (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets and Liabilities, Measured at Fair Value Recurring Basis [Table Text Block]	The following table presents a summary of fair value measurements by level and carrying values for items measured at fair value on a recurring basis in the Condensed Consolidated Balance Sheets excluding assets and liabilities, related to a Supplemental Health Insurance Program (AARP Program), which are presented in a separate table below:
	(in millions)	Quoted Prices			Other			Unobservable			Total
		in Active			Observable			Inputs			Fair and Carrying
		Markets			Inputs			(Level 3)			Value
		(Level 1)			(Level 2)
	March 31, 2015
	Cash and cash equivalents	$	8,617		$	33		$	—		$	8,650
	Debt securities - available-for-sale:
	U.S. government and agency obligations	1,466			216			—			1,682
	State and municipal obligations	—			6,693			—			6,693
	Corporate obligations	7			7,736			73			7,816
	U.S. agency mortgage-backed securities	—			2,056			—			2,056
	Non-U.S. agency mortgage-backed securities	—			866			6			872
	Total debt securities - available-for-sale	1,473			17,567			79			19,119
	Equity securities - available-for-sale	1,209			12			309			1,530
	Interest rate swap assets	—			230			—			230
	Total assets at fair value	$	11,299		$	17,842		$	388		$	29,529
	Percentage of total assets at fair value	38		%	61		%	1		%	100		%
	Interest rate swap liabilities	$	—		$	1		$	—		$	1
	December 31, 2014
	Cash and cash equivalents	$	7,472		$	23		$	—		$	7,495
	Debt securities - available-for-sale:
	U.S. government and agency obligations	1,427			193			—			1,620
	State and municipal obligations	—			6,668			—			6,668
	Corporate obligations	2			7,257			68			7,327
	U.S. agency mortgage-backed securities	—			2,056			—			2,056
	Non-U.S. agency mortgage-backed securities	—			874			6			880
	Total debt securities - available-for-sale	1,429			17,048			74			18,551
	Equity securities - available-for-sale	1,200			12			310			1,522
	Interest rate swap assets	—			62			—			62
	Total assets at fair value	$	10,101		$	17,145		$	384		$	27,630
	Percentage of total assets at fair value	37		%	62		%	1		%	100		%
	Interest rate swap liabilities	$	—		$	55		$	—		$	55
Fair Value Measurements, Nonrecurring [Table Text Block]	The following table presents a summary of fair value measurements by level and carrying values for certain financial instruments not measured at fair value on a recurring basis in the Condensed Consolidated Balance Sheets:
	(in millions)	Quoted Prices			Other			Unobservable			Total			Total Carrying Value
		in Active			Observable			Inputs			Fair
		Markets			Inputs			(Level 3)			Value
		(Level 1)			(Level 2)
	March 31, 2015
	Debt securities - held-to-maturity:
	U.S. government and agency obligations	$	182		$	—		$	—		$	182		$	178
	State and municipal obligations	—			—			15			15			15
	Corporate obligations	93			10			251			354			354
	Total debt securities - held-to-maturity	$	275		$	10		$	266		$	551		$	547
	Other assets	$	—		$	490		$	—		$	490		$	489
	Long-term debt and other financing obligations	$	—		$	18,826		$	—		$	18,826		$	16,859
	December 31, 2014
	Debt securities - held-to-maturity:
	U.S. government and agency obligations	$	180		$	—		$	—		$	180		$	178
	State and municipal obligations	—			—			19			19			19
	Corporate obligations	46			10			242			298			298
	Total debt securities - held-to-maturity	$	226		$	10		$	261		$	497		$	495
	Other assets	$	—		$	478		$	—		$	478		$	484
	Long-term debt and other financing obligations	$	—		$	18,863		$	—		$	18,863		$	17,085
Reconciliation of Assets Measured at Fair Value on a Recurring Basis Using Level 3 Inputs [Table Text Block]	A reconciliation of the beginning and ending balances of assets measured at fair value on a recurring basis using Level 3 inputs is as follows:
		31-Mar-15									31-Mar-14
	(in millions)	Debt			Equity			Total			Debt			Equity			Total
		Securities			Securities						Securities			Securities
	Balance at beginning of period	$	74		$	310		$	384		$	42		$	269		$	311
	Purchases	4			4			8			3			44			47
	Sales	—			(1		)	(1		)	—			(4		)	(4		)
	Net unrealized gains (losses) in accumulated other comprehensive income	1			(5		)	(4		)	1			4			5
	Net realized gains in investment and other income	—			1			1			—			—			—
	Balance at end of period	$	79		$	309		$	388		$	46		$	313		$	359
Fair Value Inputs, Assets, Quantitative Information [Table Text Block]	The following table presents quantitative information regarding unobservable inputs that were significant to the valuation of assets measured at fair value on a recurring basis using Level 3 inputs:
								Range
	(in millions)	Fair Value			Valuation Technique		Unobservable Input	Low		High
	March 31, 2015
	Equity securities - available-for-sale
	Venture capital portfolios	$	259		Market approach - comparable companies		Revenue multiple	1		7
							EBITDA multiple	8		10
		50			Market approach - recent transactions		Inactive market transactions	N/A		N/A
	Total equity securities	$	309
	available-for-sale
AARP Program [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Assets and Liabilities, Measured at Fair Value Recurring Basis [Table Text Block]	The following table presents fair value information about the AARP Program-related financial assets and liabilities:
	(in millions)	Quoted Prices			Other			Total
		in Active			Observable			Fair and Carrying
		Markets			Inputs			Value
		(Level 1)			(Level 2)
	March 31, 2015
	Cash and cash equivalents	$	262		$	—		$	262
	Debt securities:
	U.S. government and agency obligations	407			214			621
	State and municipal obligations	—			96			96
	Corporate obligations	—			1,279			1,279
	U.S. agency mortgage-backed securities	—			375			375
	Non-U.S. agency mortgage-backed securities	—			203			203
	Total debt securities	407			2,167			2,574
	Other investments	—			85			85
	Total assets at fair value	$	669		$	2,252		$	2,921
	Other liabilities	$	8		$	24		$	32
	December 31, 2014
	Cash and cash equivalents	$	415		$	—		$	415
	Debt securities:
	U.S. government and agency obligations	409			245			654
	State and municipal obligations	—			95			95
	Corporate obligations	—			1,200			1,200
	U.S. agency mortgage-backed securities	—			340			340
	Non-U.S. agency mortgage-backed securities	—			177			177
	Total debt securities	409			2,057			2,466
	Other investments	—			81			81
	Total assets at fair value	$	824		$	2,138		$	2,962
	Other liabilities	$	5		$	13		$	18

Medicare_Part_D_Pharmacy_Benef1

Medicare Part D Pharmacy Benefits (Tables)	3 Months Ended
	Mar. 31, 2015
Schedule of Other Current Receivables and Other Policy Liabilities Associated with Medicare Part D Program [Table Text Block]	The Condensed Consolidated Balance Sheets include the following amounts associated with the Medicare Part D program:
		March 31, 2015						December 31, 2014
	(in millions)	Subsidies		Drug Discount		Risk-Share		Subsidies		Drug Discount		Risk-Share
	Other current receivables	$	1,448	$	239	$	46	$	1,801	$	719	$	20
	Other policy liabilities	—		—		—		—		302		—

Commercial_Paper_and_LongTerm_1

Commercial Paper and Long-Term Debt (Tables)	3 Months Ended
	Mar. 31, 2015
Debt Instrument [Line Items]
Commercial Paper and Long-Term Debt [Table Text Block]	Commercial paper and senior unsecured long-term debt consisted of the following:
			March 31, 2015								December 31, 2014
	(in millions, except percentages)		Par			Carrying			Fair		Par		Carrying		Fair
			Value			Value			Value		Value		Value		Value
	Commercial paper		$	1,515		$	1,515		$	1,515	$	321	$	321	$	321
	4.875% notes due March 2015 (a)		—			—			—		416		419		419
	0.850% notes due October 2015 (a)		625			626			626		625		625		627
	5.375% notes due March 2016 (a)		601			620			627		601		623		634
	1.875% notes due November 2016 (a)		400			400			407		400		397		406
	5.360% notes due November 2016		95			95			102		95		95		103
	6.000% notes due June 2017 (a)		441			467			488		441		466		489
	1.400% notes due October 2017 (a)		625			624			631		625		616		624
	6.000% notes due November 2017 (a)		156			165			175		156		164		175
	1.400% notes due December 2017 (a)		750			755			756		750		745		749
	6.000% notes due February 2018 (a)		1,100			1,120			1,245		1,100		1,106		1,238
	1.625% notes due March 2019 (a)		500			506			501		500		496		493
	2.300% notes due December 2019 (a)		500			508			510		500		496		502
	3.875% notes due October 2020 (a)		450			463			492		450		450		477
	4.700% notes due February 2021 (a)		400			424			456		400		413		450
	3.375% notes due November 2021 (a)		500			512			534		500		496		519
	2.875% notes due December 2021 (a)		750			773			770		750		748		759
	2.875% notes due March 2022 (a)		1,100			1,082			1,119		1,100		1,042		1,104
	0.000% notes due November 2022		15			10			11		15		10		11
	2.750% notes due February 2023 (a)		625			628			631		625		604		613
	2.875% notes due March 2023 (a)		750			806			768		750		777		745
	5.800% notes due March 2036		850			845			1,096		850		845		1,052
	6.500% notes due June 2037		500			495			703		500		495		670
	6.625% notes due November 2037		650			646			927		650		646		888
	6.875% notes due February 2038		1,100			1,085			1,584		1,100		1,085		1,544
	5.700% notes due October 2040		300			298			387		300		298		378
	5.950% notes due February 2041		350			348			471		350		348		455
	4.625% notes due November 2041		600			593			677		600		593		646
	4.375% notes due March 2042		502			486			553		502		486		536
	3.950% notes due October 2042		625			611			640		625		611		621
	4.250% notes due March 2043		750			740			811		750		740		786
	Total commercial paper and long-term debt		$	18,125		$	18,246		$	20,213	$	17,347	$	17,256	$	19,034
	(a)	Fixed-rate debt instruments hedged with interest rate swap contracts. See below for more information on the Company’s interest rate swaps.
Schedule of Derivatives Instruments Statements of Financial Performance and Financial Position, Location [Table Text Block]	The following table summarizes the location and fair value of the interest rate swap fair value hedges on the Company’s Condensed Consolidated Balance Sheet:
	Type of Fair Value Hedge		Notional Amount			Fair Value			Balance Sheet Location
			(in billions)			(in millions)
	March 31, 2015
	Interest rate swap contracts		$	10.3		$	2		Prepaid expenses and other current assets
						228			Other assets
						1			Other liabilities
	31-Dec-14
	Interest rate swap contracts		$	10.7		$	62		Other assets
						55			Other liabilities
Derivative Instruments, Gain (Loss) [Table Text Block]	The following table provides a summary of the effect of changes in fair value of fair value hedges on the Company’s Condensed Consolidated Statements of Operations:
			Three Months Ended March 31,
	(in millions)		2015			2014
	Hedge - interest rate swap gain recognized in interest expense		$	222		$	66
	Hedged item - long-term debt loss recognized in interest expense		(222		)	(66		)
	Net impact on the Company’s Condensed Consolidated Statements of Operations		$	—		$	—

ShareBased_Compensation_Tables

Share-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Option and SAR Activity [Table Text Block]	Stock option and SAR activity for the three months ended March 31, 2015 is summarized in the table below:
		Shares			Weighted-				Weighted-	Aggregate
					Average				Average	Intrinsic Value
					Exercise				Remaining
					Price				Contractual Life
		(in millions)							(in years)	(in millions)
	Outstanding at beginning of period	33			$	53
	Granted	8			109
	Exercised	(4	)		52
	Outstanding at end of period	37			66				6.3	$	1,959
	Exercisable at end of period	19			47				3.8	1,368
	Vested and expected to vest, end of period	36			65				6.2	1,920
Restricted Share Activity [Table Text Block]	Restricted share activity for the three months ended March 31, 2015 is summarized in the table below:
	(shares in millions)		Shares			Weighted-Average
						Grant Date
						Fair Value
						per Share
	Nonvested at beginning of period		9			$	61
	Granted		2			109
	Vested		(4	)		57
	Nonvested at end of period		7			78
Other Share-Based Compensation Data [Table Text Block]	Other Share-Based Compensation Data
	(in millions, except per share amounts)		Three Months Ended
			March 31,
			2015				2014
	Stock Options and SARs
	Weighted-average grant date fair value of shares granted, per share		$	23			$	22
	Total intrinsic value of stock options and SARs exercised		221				212
	Restricted Shares
	Weighted-average grant date fair value of shares granted, per share		109				70
	Total fair value of restricted shares vested		395				414
	Share-Based Compensation Items
	Share-based compensation expense, before tax		125				105
	Share-based compensation expense, net of tax effects		101				86
	Income tax benefit realized from share-based award exercises		138				119
	(in millions, except years)		March 31, 2015
	Unrecognized compensation expense related to share awards		$	618
	Weighted-average years to recognize compensation expense		1.1
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	The principal assumptions the Company used in calculating grant-date fair value for stock options and SARs were as follows:
			Three Months Ended March 31,
			2015		2014
	Risk-free interest rate		1.60%		1.70%
	Expected volatility		24.10%		39.60%
	Expected dividend yield		1.40%		1.60%
	Forfeiture rate		5.00%		5.00%
	Expected life in years		6.1		5.4

Segment_Financial_Information_1

Segment Financial Information (Tables)	3 Months Ended
	Mar. 31, 2015
Segment Reporting [Abstract]
Segment Financial Information [Table Text Block]	The following table presents the reportable segment financial information:
				Optum
	(in millions)	UnitedHealthcare		OptumHealth		OptumInsight		OptumRx		Optum Eliminations			Optum		Corporate and			Consolidated
															Eliminations
	Three Months Ended
	March 31, 2015
	Revenues - external customers:
	Premiums	$	30,905	$	769	$	—	$	—	$	—		$	769	$	—		$	31,674
	Services	1,603		521		559		23		—			1,103		—			2,706
	Products	—		5		20		1,205		—			1,230		—			1,230
	Total revenues - external customers	32,508		1,295		579		1,228		—			3,102		—			35,610
	Total revenues - intersegment	—		1,963		811		7,067		(159		)	9,682		(9,682		)	—
	Investment and other income	115		31		—		—		—			31		—			146
	Total revenues	$	32,623	$	3,289	$	1,390	$	8,295	$	(159	)	$	12,815	$	(9,682	)	$	35,756
	Earnings from operations	$	1,898	$	234	$	222	$	286	$	—		$	742	$	—		$	2,640
	Interest expense	—		—		—		—		—			—		(150		)	(150		)
	Earnings before income taxes	$	1,898	$	234	$	222	$	286	$	—		$	742	$	(150	)	$	2,490
	Three Months Ended
	31-Mar-14
	Revenues - external customers:
	Premiums	$	27,511	$	604	$	—	$	—	$	—		$	604	$	—		$	28,115
	Services	1,586		263		525		30		—			818		—			2,404
	Products	1		7		26		964		—			997		—			998
	Total revenues - external customers	29,098		874		551		994		—			2,419		—			31,517
	Total revenues - intersegment	—		1,671		696		6,464		(115		)	8,716		(8,716		)	—
	Investment and other income	156		35		—		—		—			35		—			191
	Total revenues	$	29,254	$	2,580	$	1,247	$	7,458	$	(115	)	$	11,170	$	(8,716	)	$	31,708
	Earnings from operations	$	1,404	$	211	$	197	$	242	$	—		$	650	$	—		$	2,054
	Interest expense	—		—		—		—		—			—		(160		)	(160		)
	Earnings before income taxes	$	1,404	$	211	$	197	$	242	$	—		$	650	$	(160	)	$	1,894

Investments_Narrative_Details

Investments (Narrative) (Details)	Mar. 31, 2015
	positions
Investment [Line Items]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	4,000
Total number of security positions	23,000

Investments_ShortTerm_and_Long

Investments (Short-Term and Long-Term Investments) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Schedule of Investments [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	$18,664	$18,205
Securities, Available for sale Debt Securities, Gross Unrealized Gains	473	387
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	-18	-41
Available-for-sale Securities, Debt Securities	19,119	18,551
Available-for-sale Equity Securities, Amortized Cost Basis	1,526	1,511
Securities, Available for sale Equity Securities, Gross Unrealized Gains	37	36
Securities, Available for sale Equity Securities, Gross Unrealized Losses	-33	-25
Available-for-sale Securities, Equity Securities	1,530	1,522
Held-to-maturity securities, Amortized Cost	547	495
Securities, Held to maturity, Unrecognized Holding Gain	4	2
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0	0
Held-to-maturity Securities, Fair Value	551	497
Total investments, Amortized Cost	20,737	20,211
Total investments, Gross Unrealized Gains	514	425
Total investments, Gross Unrealized Losses	-51	-66
Investments, Fair Value Disclosure	21,200	20,570
Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Debt Securities	19,119	18,551
U.S. Government and Agency Obligations [Member]
Schedule of Investments [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	1,663	1,614
Securities, Available for sale Debt Securities, Gross Unrealized Gains	19	7
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	0	-1
Available-for-sale Securities, Debt Securities	1,682	1,620
Held-to-maturity securities, Amortized Cost	178	178
Securities, Held to maturity, Unrecognized Holding Gain	4	2
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0	0
Held-to-maturity Securities, Fair Value	182	180
State and Municipal Obligations [Member]
Schedule of Investments [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	6,464	6,456
Securities, Available for sale Debt Securities, Gross Unrealized Gains	232	217
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	-3	-5
Available-for-sale Securities, Debt Securities	6,693	6,668
Held-to-maturity securities, Amortized Cost	15	19
Securities, Held to maturity, Unrecognized Holding Gain	0	0
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0	0
Held-to-maturity Securities, Fair Value	15	19
Corporate Obligations [Member]
Schedule of Investments [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	7,668	7,241
Securities, Available for sale Debt Securities, Gross Unrealized Gains	158	112
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	-10	-26
Available-for-sale Securities, Debt Securities	7,816	7,327
Held-to-maturity securities, Amortized Cost	354	298
Securities, Held to maturity, Unrecognized Holding Gain	0	0
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0	0
Held-to-maturity Securities, Fair Value	354	298
U.S. Agency Mortgage-Backed Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	2,011	2,022
Securities, Available for sale Debt Securities, Gross Unrealized Gains	48	39
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	-3	-5
Available-for-sale Securities, Debt Securities	2,056	2,056
Non-U.S. Agency Mortgage-Backed Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	858	872
Securities, Available for sale Debt Securities, Gross Unrealized Gains	16	12
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	-2	-4
Available-for-sale Securities, Debt Securities	$872	$880

Investments_Amortized_Cost_and

Investments (Amortized Cost and Fair Value of Available-for-Sale Debt Securities by Contractual Maturity) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Schedule of Investments [Line Items]
Due in one year or less, Amortized Cost	$1,856
Due after one year through five years, Amortized Cost	6,927
Due after five years through ten years, Amortized Cost	5,205
Due after ten years, Amortized Cost	1,807
Total debt securities - available-for-sale, Amortized Cost	18,664	18,205
Due in one year or less, Fair Value	1,862
Due after one year through five years, Fair Value	7,035
Due after five years through ten years, Fair Value	5,387
Due after ten years, Fair Value	1,907
Available-for-sale Securities, Debt Securities	19,119	18,551
U.S. Agency Mortgage-Backed Securities [Member]
Schedule of Investments [Line Items]
Mortgage-backed securities, Amortized Cost	2,011
Total debt securities - available-for-sale, Amortized Cost	2,011	2,022
Mortgage-backed securities, Fair Value	2,056
Available-for-sale Securities, Debt Securities	2,056	2,056
Non-U.S. Agency Mortgage-Backed Securities [Member]
Schedule of Investments [Line Items]
Mortgage-backed securities, Amortized Cost	858
Total debt securities - available-for-sale, Amortized Cost	858	872
Mortgage-backed securities, Fair Value	872
Available-for-sale Securities, Debt Securities	$872	$880

Investments_Amortized_Cost_and1

Investments (Amortized Cost and Fair Value of Held-To-Maturity Debt Securities by Contractual Maturity) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Schedule of Held-to-maturity Securities [Line Items]
Due in one year or less, Amortized Cost	$127
Due after one year through five years, Amortized Cost	207
Due after five years through ten years, Amortized Cost	109
Due after ten years, Amortized Cost	104
Held-to-maturity securities, Amortized Cost	547	495
Due in one year or less, Fair Value	127
Due after one year through five years, Fair Value	209
Due after five years through ten years, Fair Value	110
Due after ten years, Fair Value	105
Total debt securities - held-to-maturity, Fair Value	$551	$497

Investments_Fair_Value_of_Avai

Investments (Fair Value of Available-For-Sale Investments with Gross Unrealized Losses by Investment Type and Length of Time That Individual Securities Have Been in a Continuous Unrealized Loss Position) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Debt Securities [Member]
Schedule of Investments [Line Items]
Less Than 12 Months, Fair Value	$2,327	$3,980
Less Than 12 Months, Gross Unrealized Losses	-12	-24
Greater Than 12 Months, Fair Value	395	949
Greater Than 12 Months, Gross Unrealized Losses	-6	-17
Total, Fair Value	2,722	4,929
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	-18	-41
U.S. Government and Agency Obligations [Member]
Schedule of Investments [Line Items]
Less Than 12 Months, Fair Value		420
Less Than 12 Months, Gross Unrealized Losses		-1
Total, Fair Value		420
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		-1
State and Municipal Obligations [Member]
Schedule of Investments [Line Items]
Less Than 12 Months, Fair Value	481	711
Less Than 12 Months, Gross Unrealized Losses	-2	-4
Greater Than 12 Months, Fair Value	27	99
Greater Than 12 Months, Gross Unrealized Losses	-1	-1
Total, Fair Value	508	810
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	-3	-5
Corporate Obligations [Member]
Schedule of Investments [Line Items]
Less Than 12 Months, Fair Value	1,509	2,595
Less Than 12 Months, Gross Unrealized Losses	-7	-17
Greater Than 12 Months, Fair Value	235	464
Greater Than 12 Months, Gross Unrealized Losses	-3	-9
Total, Fair Value	1,744	3,059
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	-10	-26
U.S. Agency Mortgage-Backed Securities [Member]
Schedule of Investments [Line Items]
Less Than 12 Months, Fair Value	151
Less Than 12 Months, Gross Unrealized Losses	-1
Greater Than 12 Months, Fair Value	133	272
Greater Than 12 Months, Gross Unrealized Losses	-2	-5
Total, Fair Value	284	272
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	-3	-5
Non-U.S. Agency Mortgage-Backed Securities [Member]
Schedule of Investments [Line Items]
Less Than 12 Months, Fair Value	186	254
Less Than 12 Months, Gross Unrealized Losses	-2	-2
Greater Than 12 Months, Fair Value		114
Greater Than 12 Months, Gross Unrealized Losses		-2
Total, Fair Value	186	368
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	-2	-4
Equity Securities [Member]
Schedule of Investments [Line Items]
Less Than 12 Months, Fair Value	76	107
Less Than 12 Months, Gross Unrealized Losses	-7	-6
Greater Than 12 Months, Fair Value	83	88
Greater Than 12 Months, Gross Unrealized Losses	-26	-19
Total, Fair Value	159	195
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	($33)	($25)

Investments_Net_Realized_Gains

Investments (Net Realized Gains) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Income tax effect (included in Provision for Income Taxes on the Condensed Consolidated Statements of Operations)	($1,077)	($795)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Schedule of Available-for-sale Securities [Line Items]
Total OTTI	-1	-3
Portion of loss recognized in other comprehensive income	0	0
Net OTTI recognized in earnings	-1	-3
Gross realized losses from sales	-6	-10
Gross realized gains from sales	10	59
Net realized gains (included in investment and other income on the Condensed Consolidated Statements of Operations)	3	46
Income tax effect (included in Provision for Income Taxes on the Condensed Consolidated Statements of Operations)	-1	-17
Realized gains, net of taxes	$2	$29

Fair_Value_Narrative_Details

Fair Value (Narrative) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Fair Value [Line Items]
Transfers from level 1 to level 2-Assets	$0	$0
Transfers from level 1 to level 2-Liabilities	0	0
Transfer from level 2 to level 1-Assets	0	0
Transfer from level 2 to level 1-Liabilities	0	0
Transfers Into Level 3	0	0
Transfers out of Level 3	0	0
Fair Value, Measurements, Nonrecurring [Member]
Fair Value [Line Items]
Significant fair value adjustments for assets and liabilities measured on a nonrecurring basis	0	0
Fair Value, Measurements, Recurring [Member] | Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value [Line Items]
Available-for-sale Securities	$79

Fair_Value_Financial_Assets_an

Fair Value (Financial Assets and Liabilities, Excluding AARP, Measured at Fair Value on a Recurring Basis) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$8,650	$7,495
Available-for-sale Securities, Debt Securities	19,119	18,551
Available-for-sale Securities, Equity Securities	1,530	1,522
Interest rate swap assets	230	62
Total assets at fair value	29,529	27,630
Percentage of total assets at fair value	100.00%	100.00%
Interest rate swap liabilities	1	55
Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	19,119	18,551
U.S. Government and Agency Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	1,682	1,620
State and Municipal Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	6,693	6,668
Corporate Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	7,816	7,327
U.S. Agency Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	2,056	2,056
Non-U.S. Agency Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	872	880
Quoted Prices in Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	8,617	7,472
Available-for-sale Securities, Equity Securities	1,209	1,200
Interest rate swap assets	0	0
Total assets at fair value	11,299	10,101
Percentage of total assets at fair value	38.00%	37.00%
Interest rate swap liabilities	0	0
Quoted Prices in Active Markets (Level 1) [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	1,473	1,429
Quoted Prices in Active Markets (Level 1) [Member] | U.S. Government and Agency Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	1,466	1,427
Quoted Prices in Active Markets (Level 1) [Member] | State and Municipal Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	0	0
Quoted Prices in Active Markets (Level 1) [Member] | Corporate Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	7	2
Quoted Prices in Active Markets (Level 1) [Member] | U.S. Agency Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	0	0
Quoted Prices in Active Markets (Level 1) [Member] | Non-U.S. Agency Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	0	0
Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	33	23
Available-for-sale Securities, Equity Securities	12	12
Interest rate swap assets	230	62
Total assets at fair value	17,842	17,145
Percentage of total assets at fair value	61.00%	62.00%
Interest rate swap liabilities	1	55
Other Observable Inputs (Level 2) [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	17,567	17,048
Other Observable Inputs (Level 2) [Member] | U.S. Government and Agency Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	216	193
Other Observable Inputs (Level 2) [Member] | State and Municipal Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	6,693	6,668
Other Observable Inputs (Level 2) [Member] | Corporate Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	7,736	7,257
Other Observable Inputs (Level 2) [Member] | U.S. Agency Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	2,056	2,056
Other Observable Inputs (Level 2) [Member] | Non-U.S. Agency Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	866	874
Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Available-for-sale Securities, Equity Securities	309	310
Interest rate swap assets	0	0
Total assets at fair value	388	384
Percentage of total assets at fair value	1.00%	1.00%
Interest rate swap liabilities	0	0
Unobservable Inputs (Level 3) [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	79	74
Unobservable Inputs (Level 3) [Member] | U.S. Government and Agency Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	0	0
Unobservable Inputs (Level 3) [Member] | State and Municipal Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	0	0
Unobservable Inputs (Level 3) [Member] | Corporate Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	73	68
Unobservable Inputs (Level 3) [Member] | U.S. Agency Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	0	0
Unobservable Inputs (Level 3) [Member] | Non-U.S. Agency Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	$6	$6

Fair_Value_Financial_Assets_an1

Fair Value (Financial Assets and Liabilities, Excluding AARP, Not Measured at Fair Value on a Recurring Basis) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	$551	$497
Debt securities - held-to-maturity	547	495
Long-term Debt, Gross	18,246	17,256
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	551	497
Fair Value, Measurements, Nonrecurring [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	275	226
Fair Value, Measurements, Nonrecurring [Member] | Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	10	10
Fair Value, Measurements, Nonrecurring [Member] | Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	266	261
U.S. Government and Agency Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	182	180
U.S. Government and Agency Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	182	180
U.S. Government and Agency Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member] | Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	0	0
U.S. Government and Agency Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member] | Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	0	0
State and Municipal Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	15	19
State and Municipal Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	0	0
State and Municipal Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member] | Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	0	0
State and Municipal Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member] | Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	15	19
Corporate Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	354	298
Corporate Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	93	46
Corporate Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member] | Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	10	10
Corporate Obligations [Member] | Fair Value, Measurements, Nonrecurring [Member] | Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	251	242
Long-term debt and other financing obligations | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	18,826	18,863
Long-term debt and other financing obligations | Fair Value, Measurements, Nonrecurring [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	0	0
Long-term debt and other financing obligations | Fair Value, Measurements, Nonrecurring [Member] | Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	18,826	18,863
Long-term debt and other financing obligations | Fair Value, Measurements, Nonrecurring [Member] | Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	0	0
Other Assets [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	490	478
Other Assets [Member] | Fair Value, Measurements, Nonrecurring [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	0	0
Other Assets [Member] | Fair Value, Measurements, Nonrecurring [Member] | Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	490	478
Other Assets [Member] | Fair Value, Measurements, Nonrecurring [Member] | Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	0	0
Reported Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities - held-to-maturity	547	495
Reported Value Measurement [Member] | U.S. Government and Agency Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities - held-to-maturity	178	178
Reported Value Measurement [Member] | State and Municipal Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities - held-to-maturity	15	19
Reported Value Measurement [Member] | Corporate Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities - held-to-maturity	354	298
Reported Value Measurement [Member] | Long-term debt and other financing obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Gross	16,859	17,085
Reported Value Measurement [Member] | Other Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	$489	$484

Fair_Value_Reconciliation_of_A

Fair Value (Reconciliation of Assets Measured at Fair Value on a Recurring Basis Using Level 3 Inputs) (Details) (Fair Value, Measurements, Recurring [Member], USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$384	$311
Purchases	8	47
Sales	-1	-4
Net unrealized gains (losses) in accumulated other comprehensive income	-4	5
Net realized gains in investment and other income	1	0
Balance at end of period	388	359
Debt Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	74	42
Purchases	4	3
Sales	0	0
Net unrealized gains (losses) in accumulated other comprehensive income	1	1
Net realized gains in investment and other income	0	0
Balance at end of period	79	46
Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	310	269
Purchases	4	44
Sales	-1	-4
Net unrealized gains (losses) in accumulated other comprehensive income	-5	4
Net realized gains in investment and other income	1	0
Balance at end of period	$309	$313

Fair_Value_Fair_Value_Inputs_A

Fair Value Fair Value Inputs Assets Quantitative Information (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015
Venture Capital Funds [Member] | Market Approach Valuation Technique [Member] | Comparable Companies [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	259
Venture Capital Funds [Member] | Market Approach Valuation Technique [Member] | Recent Transactions [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	50
Minimum [Member] | Market Approach Valuation Technique [Member] | Comparable Companies [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Revenue Multiple	1
Fair Value Inputs, Earnings before Interest, Taxes, Depreciation, and Amortization Multiple	8
Maximum [Member] | Market Approach Valuation Technique [Member] | Comparable Companies [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Revenue Multiple	7
Fair Value Inputs, Earnings before Interest, Taxes, Depreciation, and Amortization Multiple	10
Unobservable Inputs (Level 3) [Member] | Equity Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	309

Fair_Value_Assets_and_Liabilit

Fair Value (Assets and Liabilities measured at fair value on a recurring basis) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$8,650	$7,495
Available-for-sale Securities, Debt Securities	19,119	18,551
Total assets at fair value	29,529	27,630
Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	19,119	18,551
U.S. Government and Agency Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	1,682	1,620
State and Municipal Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	6,693	6,668
Corporate Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	7,816	7,327
U.S. Agency Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	2,056	2,056
Non-U.S. Agency Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	872	880
Quoted Prices in Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	8,617	7,472
Total assets at fair value	11,299	10,101
Quoted Prices in Active Markets (Level 1) [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	1,473	1,429
Quoted Prices in Active Markets (Level 1) [Member] | U.S. Government and Agency Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	1,466	1,427
Quoted Prices in Active Markets (Level 1) [Member] | State and Municipal Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	0	0
Quoted Prices in Active Markets (Level 1) [Member] | Corporate Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	7	2
Quoted Prices in Active Markets (Level 1) [Member] | U.S. Agency Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	0	0
Quoted Prices in Active Markets (Level 1) [Member] | Non-U.S. Agency Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	0	0
Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	33	23
Total assets at fair value	17,842	17,145
Other Observable Inputs (Level 2) [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	17,567	17,048
Other Observable Inputs (Level 2) [Member] | U.S. Government and Agency Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	216	193
Other Observable Inputs (Level 2) [Member] | State and Municipal Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	6,693	6,668
Other Observable Inputs (Level 2) [Member] | Corporate Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	7,736	7,257
Other Observable Inputs (Level 2) [Member] | U.S. Agency Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	2,056	2,056
Other Observable Inputs (Level 2) [Member] | Non-U.S. Agency Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	866	874
Fair Value, Measurements, Recurring [Member] | AARP Program [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	262	415
Other Investments	85	81
Total assets at fair value	2,921	2,962
Other liabilities	32	18
Fair Value, Measurements, Recurring [Member] | Debt Securities [Member] | AARP Program [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	2,574	2,466
Fair Value, Measurements, Recurring [Member] | U.S. Government and Agency Obligations [Member] | AARP Program [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	621	654
Fair Value, Measurements, Recurring [Member] | State and Municipal Obligations [Member] | AARP Program [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	96	95
Fair Value, Measurements, Recurring [Member] | Corporate Obligations [Member] | AARP Program [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	1,279	1,200
Fair Value, Measurements, Recurring [Member] | U.S. Agency Mortgage-Backed Securities [Member] | AARP Program [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	375	340
Fair Value, Measurements, Recurring [Member] | Non-U.S. Agency Mortgage-Backed Securities [Member] | AARP Program [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	203	177
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets (Level 1) [Member] | AARP Program [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	262	415
Other Investments	0	0
Total assets at fair value	669	824
Other liabilities	8	5
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets (Level 1) [Member] | Debt Securities [Member] | AARP Program [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	407	409
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets (Level 1) [Member] | U.S. Government and Agency Obligations [Member] | AARP Program [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	407	409
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets (Level 1) [Member] | State and Municipal Obligations [Member] | AARP Program [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	0	0
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets (Level 1) [Member] | Corporate Obligations [Member] | AARP Program [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	0	0
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets (Level 1) [Member] | U.S. Agency Mortgage-Backed Securities [Member] | AARP Program [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	0	0
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets (Level 1) [Member] | Non-U.S. Agency Mortgage-Backed Securities [Member] | AARP Program [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	0	0
Fair Value, Measurements, Recurring [Member] | Other Observable Inputs (Level 2) [Member] | AARP Program [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Other Investments	85	81
Total assets at fair value	2,252	2,138
Other liabilities	24	13
Fair Value, Measurements, Recurring [Member] | Other Observable Inputs (Level 2) [Member] | Debt Securities [Member] | AARP Program [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	2,167	2,057
Fair Value, Measurements, Recurring [Member] | Other Observable Inputs (Level 2) [Member] | U.S. Government and Agency Obligations [Member] | AARP Program [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	214	245
Fair Value, Measurements, Recurring [Member] | Other Observable Inputs (Level 2) [Member] | State and Municipal Obligations [Member] | AARP Program [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	96	95
Fair Value, Measurements, Recurring [Member] | Other Observable Inputs (Level 2) [Member] | Corporate Obligations [Member] | AARP Program [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	1,279	1,200
Fair Value, Measurements, Recurring [Member] | Other Observable Inputs (Level 2) [Member] | U.S. Agency Mortgage-Backed Securities [Member] | AARP Program [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	375	340
Fair Value, Measurements, Recurring [Member] | Other Observable Inputs (Level 2) [Member] | Non-U.S. Agency Mortgage-Backed Securities [Member] | AARP Program [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Securities	$203	$177

Medicare_Part_D_Pharmacy_Benef2

Medicare Part D Pharmacy Benefits Medicare Part D Schedule of Receivables and Payables (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Other current receivables	$5,346	$5,498
Other policy liabilities	6,392	5,965
CMS Subsidies [Member]
Other current receivables	1,448	1,801
Other policy liabilities	0	0
Drug Discount [Member]
Other current receivables	239	719
Other policy liabilities	0	302
Risk-Share [Member]
Other current receivables	46	20
Other policy liabilities	$0	$0

Medical_Costs_Reserve_Developm1

Medical Costs Reserve Development (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Medical Reserve Development [Abstract]
Supplemental Information For Prior Year Claims and Claims Adjustment Expense	$140	$220

Health_Insurance_Industry_Tax_1

Health Insurance Industry Tax (Details) (Health Insurance Industry Tax [Member], USD $)	Mar. 31, 2015	Dec. 31, 2014
In Billions, unless otherwise specified
Health Insurance Industry Tax [Member]
Accrued Liabilities, Current	$1.80	$0
Deferred Costs, Current	$1.40	$0

Commercial_Paper_and_LongTerm_2

Commercial Paper and Long-Term Debt (Narrative) (Details) (USD $)	3 Months Ended	0 Months Ended
	Mar. 31, 2015	1-May-15	Dec. 31, 2014
Debt Instrument [Line Items]
Other Long-term Debt	$128,000,000		$150,000,000
Other Long-term Debt, Current	36,000,000		34,000,000
Commercial Paper [Member]
Debt Instrument [Line Items]
Short-term Debt, Weighted Average Interest Rate	0.30%
Five Year $3.0 Billion Credit Facility [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit	0
Line of Credit, Credit Facility, Maximum Borrowing Capacity	3,000,000,000
Number Of Years Of Revolving Bank Credit	5 years
Number of banks that comprise revolving bank credit facility (banks)	23
Maximum percentage of indebtedness to total net capital bank covenant	50.00%
Five Year $3.0 Billion Credit Facility [Member] | Minimum [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate During Period	1.00%
Five Year $3.0 Billion Credit Facility [Member] | Maximum [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate During Period	1.20%
364 Day $1.0 Billion Credit Facility [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit	0
Line of Credit, Credit Facility, Maximum Borrowing Capacity	1,000,000,000
Credit Facility, Number of Days	364
Number of banks that comprise revolving bank credit facility (banks)	23
Maximum percentage of indebtedness to total net capital bank covenant	50.00%
364 Day $1.0 Billion Credit Facility [Member] | Minimum [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate During Period	1.00%
364 Day $1.0 Billion Credit Facility [Member] | Maximum [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate During Period	1.20%
Subsequent Event [Member] | 364 Day $2.0 Billion Credit Facility [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit		0
Line of Credit, Credit Facility, Maximum Borrowing Capacity		2,000,000,000
Credit Facility, Number of Days		364
Subsequent Event [Member] | Delayed Draw Term Loan [Member]
Debt Instrument [Line Items]
Debt Instrument, Unused Borrowing Capacity, Amount		$1,500,000,000

Commercial_Paper_and_LongTerm_3

Commercial Paper and Long-Term Debt (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Millions, unless otherwise specified
Debt Instrument [Line Items]
Par Value	$18,125		$17,347
Carrying Value	18,246		17,256
Fair Value	20,213		19,034
Commercial Paper [Member]
Debt Instrument [Line Items]
Par Value	1,515		321
Commercial Paper	1,515		321
Debt Instrument, Fair Value Disclosure	1,515		321
4.875% Notes Due March 2015 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.88%
Par Value	0	[1]	416	[1]
Carrying Value	0	[1]	419	[1]
Fair Value	0	[1]	419	[1]
0.850% Notes due October 2015 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	0.85%
Par Value	625	[1]	625	[1]
Carrying Value	626	[1]	625	[1]
Fair Value	626	[1]	627	[1]
5.375% Notes Due March 2016 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.38%
Par Value	601	[1]	601	[1]
Carrying Value	620	[1]	623	[1]
Fair Value	627	[1]	634	[1]
1.875% Notes Due November 2016 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.88%
Par Value	400	[1]	400	[1]
Carrying Value	400	[1]	397	[1]
Fair Value	407	[1]	406	[1]
5.360% Notes Due November 2016 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.36%
Par Value	95		95
Carrying Value	95		95
Fair Value	102		103
6.000% Notes Due June 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.00%
Par Value	441	[1]	441	[1]
Carrying Value	467	[1]	466	[1]
Fair Value	488	[1]	489	[1]
1.400% Notes due October 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.40%
Par Value	625	[1]	625	[1]
Carrying Value	624	[1]	616	[1]
Fair Value	631	[1]	624	[1]
6.000% Notes Due November 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.00%
Par Value	156	[1]	156	[1]
Carrying Value	165	[1]	164	[1]
Fair Value	175	[1]	175	[1]
1.400% Notes Due December 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.40%
Par Value	750	[1]	750	[1]
Carrying Value	755	[1]	745	[1]
Fair Value	756	[1]	749	[1]
6.000% Notes Due February 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.00%
Par Value	1,100	[1]	1,100	[1]
Carrying Value	1,120	[1]	1,106	[1]
Fair Value	1,245	[1]	1,238	[1]
1.625% Notes Due March 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.63%
Par Value	500	[1]	500	[1]
Carrying Value	506	[1]	496	[1]
Fair Value	501	[1]	493	[1]
2.300% Notes Due December 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.30%
Par Value	500	[1]	500	[1]
Carrying Value	508	[1]	496	[1]
Fair Value	510	[1]	502	[1]
3.875% Notes Due October 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.88%
Par Value	450	[1]	450	[1]
Carrying Value	463	[1]	450	[1]
Fair Value	492	[1]	477	[1]
4.700% Notes Due February 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.70%
Par Value	400	[1]	400	[1]
Carrying Value	424	[1]	413	[1]
Fair Value	456	[1]	450	[1]
3.375% Notes Due November 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.38%
Par Value	500	[1]	500	[1]
Carrying Value	512	[1]	496	[1]
Fair Value	534	[1]	519	[1]
2.875% Notes Due December 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.88%
Par Value	750	[1]	750	[1]
Carrying Value	773	[1]	748	[1]
Fair Value	770	[1]	759	[1]
2.875% Notes Due March 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.88%
Par Value	1,100	[1]	1,100	[1]
Carrying Value	1,082	[1]	1,042	[1]
Fair Value	1,119	[1]	1,104	[1]
0.000% Notes Due November 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	0.00%
Par Value	15		15
Carrying Value	10		10
Fair Value	11		11
2.750% Notes due February 2023 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.75%
Par Value	625	[1]	625	[1]
Carrying Value	628	[1]	604	[1]
Fair Value	631	[1]	613	[1]
2.875% Notes due March 2023 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.88%
Par Value	750	[1]	750	[1]
Carrying Value	806	[1]	777	[1]
Fair Value	768	[1]	745	[1]
5.800% Notes Due March 2036 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.80%
Par Value	850		850
Carrying Value	845		845
Fair Value	1,096		1,052
6.500% Notes Due June 2037 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.50%
Par Value	500		500
Carrying Value	495		495
Fair Value	703		670
6.625% Notes Due November 2037 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.63%
Par Value	650		650
Carrying Value	646		646
Fair Value	927		888
6.875% Notes Due February 2038 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.88%
Par Value	1,100		1,100
Carrying Value	1,085		1,085
Fair Value	1,584		1,544
5.700% Notes Due October 2040 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.70%
Par Value	300		300
Carrying Value	298		298
Fair Value	387		378
5.950% Notes Due February 2041 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.95%
Par Value	350		350
Carrying Value	348		348
Fair Value	471		455
4.625% Notes Due November 2041 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.63%
Par Value	600		600
Carrying Value	593		593
Fair Value	677		646
4.375% Notes Due March 2042 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.38%
Par Value	502		502
Carrying Value	486		486
Fair Value	553		536
3.950% Notes due October 2042 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.95%
Par Value	625		625
Carrying Value	611		611
Fair Value	640		621
4.250% Notes due March 2043 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.25%
Par Value	750		750
Carrying Value	740		740
Fair Value	$811		$786
[1]	Fixed-rate debt instruments hedged with interest rate swap contracts. See below for more information on the Company’s interest rate swaps.

Commercial_Paper_and_LongTerm_4

Commercial Paper and Long-Term Debt Fair Value Hedges Statement of Financial Position Location (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Interest Rate Derivative Assets, at Fair Value	$230,000,000	$62,000,000
Interest Rate Derivative Liabilities, at Fair Value	1,000,000	55,000,000
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	10,300,000,000	10,700,000,000
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Prepaid Expenses and Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Interest Rate Derivative Assets, at Fair Value	2,000,000
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Interest Rate Derivative Assets, at Fair Value	228,000,000	62,000,000
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Interest Rate Derivative Liabilities, at Fair Value	$1,000,000	$55,000,000

Commercial_Paper_and_LongTerm_5

Commercial Paper and Long-Term Debt Fair Value Hedges Effect of Changes in Fair Value Hedges on Income (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Net impact on the Company’s Condensed Consolidated Statements of Operations	$0	$0
Interest Rate Swap [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Hedge - interest rate swap gain recognized in interest expense	222	66
Debt [Member] | Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Hedged item - long-term debt loss recognized in interest expense	($222)	($66)

ShareBased_Compensation_Stock_

Share-Based Compensation (Stock Option and SAR Activity) (Details) (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at the beginning of the period, Shares	33
Granted, Shares	8
Exercised, Shares	-4
Outstanding at the end of the period, Shares	37
Exercisable at end of period, Shares	19
Vested and expected to vest end of period, Shares	36
Outstanding at beginning of period, Weighted-Average Exercise Price	$53
Granted, Weighted-Average Exercise Price	$109
Exercised, Weighted-Average Exercise Price	$52
Outstanding at end of period, Weighted-Average Exercise Price	$66
Exercisable at end of period, Weighted-Average Exercise Price	$47
Vested and expected to vest end of period, Weighted-Average Exercise Price	$65
Outstanding at end of period, Weighted Average Remaining Contractual Term (in years)	6 years 3 months 18 days
Exercisable at end of period, Weighted Average Remaining Contractual Term (in years)	3 years 9 months 18 days
Vested and expected to vest end of period, Weighted Average Remaining Contractual Term (in years)	6 years 2 months 12 days
Outstanding at end of period, Aggregate Intrinsic Value	$1,959
Exercisable at end of period, Aggregate Intrinsic Value	1,368
Vested and expected to vest end of period, Aggregate Intrinsic Value	$1,920

ShareBased_Compensation_Restri

Share-Based Compensation (Restricted Share Activity) (Details) (Restricted Stock [Member], USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2015
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Nonvested at beginning of period, Shares	9
Granted, Shares	2
Vested, Shares	-4
Nonvested at end of period, Shares	7
Nonvested at beginning of period, Weighted-Average Grant Date Fair Value (per share)	$61
Granted, Weighted Average Grant Date Fair Value (per share)	$109
Vested, Weighted Average Grant Date Fair Value (per share)	$57
Nonvested at end of period, Weighted-Average Grant Date Fair Value (per share)	$78

ShareBased_Compensation_Other_

Share-Based Compensation Other Share-Based Compensation Data (Details) (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense, before tax	$125	$105
Share-based compensation expense, net of tax effects	101	86
Income tax benefit realized from share-based award exercises	138	119
Unrecognized compensation expense related to share awards	618
Weighted-average years to recognize compensation expense	1 year 1 month 6 days
Stock Options and SARs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value of shares granted, per share	$23	$22
Total intrinsic value of stock options and SARs exercised	221	212
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value (per share)	$109	$70
Total fair value of restricted shares vested	$395	$414

ShareBased_Compensation_ShareB

Share-Based Compensation (Share-Based Compensation Principal Fair Value Assumptions) (Details)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.60%	1.70%
Expected Volatility	24.10%	39.60%
Expected dividend yield	1.40%	1.60%
Forfeiture rate	5.00%	5.00%
Expected Life in years	6 years 1 month 6 days	5 years 4 months 24 days

Commitments_and_Contingencies_1

Commitments and Contingencies (Details) (USD $)	0 Months Ended	1 Months Ended	0 Months Ended	1 Months Ended
	Jan. 28, 2008	Aug. 31, 2013	Jun. 09, 2014	Mar. 31, 2015
California Claims Processing Matter [Member]
Commitments and Contingencies [Line Items]
Estimated Largest Aggregate Penalty Issued By Cdi				$8,000,000
CDI aggregate penalty	325,000,000
California Administrative Law Judge [Member] | Judicial Ruling [Member] | California Claims Processing Matter [Member]
Commitments and Contingencies [Line Items]
Loss Contingency, Damages Awarded, Value		11,500,000
California Insurance Commissioner [Member] | Judicial Ruling [Member] | California Claims Processing Matter [Member]
Commitments and Contingencies [Line Items]
Loss Contingency, Damages Awarded, Value			174,000,000
Catamaran [Member]
Commitments and Contingencies [Line Items]
People Served				35,000,000
Payments to be made to Acquire Businesses, Gross				$12,800,000,000
Business Acquisition, Percentage of Voting Interests to be Acquired				100.00%

Segment_Financial_Information_2

Segment Financial Information (Narrative) (Details)	3 Months Ended
	Mar. 31, 2015
Statement [Line Items]
Number of Reportable Segments	4

Segment_Financial_Information_3

Segment Financial Information (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement [Line Items]
Premiums, revenues - external customers	$31,674	$28,115
Services, revenues - external customers	2,706	2,404
Products, revenues - external customers	1,230	998
Investment and other income	146	191
Total revenues	35,756	31,708
Earnings from operations	2,640	2,054
Interest expense	-150	-160
Earnings before income taxes	2,490	1,894
Optum [Member]
Statement [Line Items]
Investment and other income	31	35
Total revenues	12,815	11,170
Earnings from operations	742	650
Interest expense	0	0
Earnings before income taxes	742	650
External Customers [Member]
Statement [Line Items]
Premiums, revenues - external customers	31,674	28,115
Services, revenues - external customers	2,706	2,404
Products, revenues - external customers	1,230	998
Total revenues	35,610	31,517
External Customers [Member] | Optum [Member]
Statement [Line Items]
Premiums, revenues - external customers	769	604
Services, revenues - external customers	1,103	818
Products, revenues - external customers	1,230	997
Total revenues	3,102	2,419
Intersegment [Member]
Statement [Line Items]
Total revenues	0	0
Intersegment [Member] | Optum [Member]
Statement [Line Items]
Total revenues	9,682	8,716
Operating Segments [Member] | UnitedHealthcare [Member]
Statement [Line Items]
Investment and other income	115	156
Total revenues	32,623	29,254
Earnings from operations	1,898	1,404
Interest expense	0	0
Earnings before income taxes	1,898	1,404
Operating Segments [Member] | Optumhealth [Member]
Statement [Line Items]
Investment and other income	31	35
Total revenues	3,289	2,580
Earnings from operations	234	211
Interest expense	0	0
Earnings before income taxes	234	211
Operating Segments [Member] | Optuminsight [Member]
Statement [Line Items]
Investment and other income	0	0
Total revenues	1,390	1,247
Earnings from operations	222	197
Interest expense	0	0
Earnings before income taxes	222	197
Operating Segments [Member] | Optumrx [Member]
Statement [Line Items]
Investment and other income	0	0
Total revenues	8,295	7,458
Earnings from operations	286	242
Interest expense	0	0
Earnings before income taxes	286	242
Operating Segments [Member] | External Customers [Member] | UnitedHealthcare [Member]
Statement [Line Items]
Premiums, revenues - external customers	30,905	27,511
Services, revenues - external customers	1,603	1,586
Products, revenues - external customers	0	1
Total revenues	32,508	29,098
Operating Segments [Member] | External Customers [Member] | Optumhealth [Member]
Statement [Line Items]
Premiums, revenues - external customers	769	604
Services, revenues - external customers	521	263
Products, revenues - external customers	5	7
Total revenues	1,295	874
Operating Segments [Member] | External Customers [Member] | Optuminsight [Member]
Statement [Line Items]
Premiums, revenues - external customers	0	0
Services, revenues - external customers	559	525
Products, revenues - external customers	20	26
Total revenues	579	551
Operating Segments [Member] | External Customers [Member] | Optumrx [Member]
Statement [Line Items]
Premiums, revenues - external customers	0	0
Services, revenues - external customers	23	30
Products, revenues - external customers	1,205	964
Total revenues	1,228	994
Operating Segments [Member] | Intersegment [Member] | UnitedHealthcare [Member]
Statement [Line Items]
Total revenues	0	0
Operating Segments [Member] | Intersegment [Member] | Optumhealth [Member]
Statement [Line Items]
Total revenues	1,963	1,671
Operating Segments [Member] | Intersegment [Member] | Optuminsight [Member]
Statement [Line Items]
Total revenues	811	696
Operating Segments [Member] | Intersegment [Member] | Optumrx [Member]
Statement [Line Items]
Total revenues	7,067	6,464
Optum Eliminations [Member]
Statement [Line Items]
Investment and other income	0	0
Total revenues	-159	-115
Earnings from operations	0	0
Interest expense	0	0
Earnings before income taxes	0	0
Optum Eliminations [Member] | External Customers [Member]
Statement [Line Items]
Premiums, revenues - external customers	0	0
Services, revenues - external customers	0	0
Products, revenues - external customers	0	0
Total revenues	0	0
Optum Eliminations [Member] | Intersegment [Member]
Statement [Line Items]
Total revenues	-159	-115
Corporate and Eliminations [Member]
Statement [Line Items]
Investment and other income	0	0
Total revenues	-9,682	-8,716
Earnings from operations	0	0
Interest expense	-150	-160
Earnings before income taxes	-150	-160
Corporate and Eliminations [Member] | External Customers [Member]
Statement [Line Items]
Premiums, revenues - external customers	0	0
Services, revenues - external customers	0	0
Products, revenues - external customers	0	0
Total revenues	0	0
Corporate and Eliminations [Member] | Intersegment [Member]
Statement [Line Items]
Total revenues	($9,682)	($8,716)