Acquisitions and Disposition (Details - Other) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended			0 Months Ended	12 Months Ended					0 Months Ended			1 Months Ended	12 Months Ended				1 Months Ended					1 Months Ended		1 Months Ended				1 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2010 Assets Disposed Of By Method Other Than Sale In Period Of Disposition Run Off Workers Compensation And Personal Accident Business [Member]	Dec. 31, 2012 Assets Disposed Of By Method Other Than Sale In Period Of Disposition Run Off Workers Compensation And Personal Accident Business [Member]	Dec. 31, 2011 Scenario, Previously Reported [Member]	Dec. 31, 2010 Scenario, Previously Reported [Member]	Dec. 31, 2011 Restatement Adjustment [Member]	Dec. 31, 2010 Restatement Adjustment [Member]	Nov. 09, 2012 Finans Emeklilik [Member]	Aug. 31, 2012 Great American Supplemental Benefits Group [Member]	Aug. 31, 2012 Great American Supplemental Benefits Group [Member] Restatement Adjustment [Member]	Jan. 31, 2012 HealthSpring [Member]	Dec. 31, 2012 HealthSpring [Member]	Dec. 31, 2011 HealthSpring [Member]	Dec. 31, 2012 HealthSpring [Member] Pre Tax [Member]	Dec. 31, 2012 HealthSpring [Member] After Tax [Member]	Jan. 31, 2012 HealthSpring [Member] Maximum [Member]	Jan. 31, 2012 HealthSpring [Member] Minimum [Member]	Jan. 31, 2012 HealthSpring [Member] Vested Options [Member]	Jan. 31, 2012 HealthSpring [Member] Unvested Options [Member]	Jan. 31, 2012 HealthSpring [Member] Restricted Stock Grants And Units [Member]	Jan. 31, 2012 HealthSpring [Member] Customer Relationships [Member]	Jan. 31, 2012 HealthSpring [Member] Other Intangibles [Member]	Jan. 31, 2012 HealthSpring [Member] Other Intangibles [Member] Maximum [Member]	Jan. 31, 2012 HealthSpring [Member] Other Intangibles [Member] Minimum [Member]	Nov. 30, 2011 FirstAssist [Member]	Nov. 30, 2011 FirstAssist [Member] Restatement Adjustment [Member]	Aug. 31, 2010 Vanbreda International [Member]
Business Acquisition, Entity Acquired and Reason for Acquisition [Abstract]
Business Acquisition Effective Date Of Acquisition																		November 09, 2012	August 31, 2012		January 31, 2012														November 2011		August 31, 2010
Business Acquisition Name Of Acquired Entity																		Finans Emeklilik ve Hayat A.S.	Great American Supplemental Benefits Group		HealthSpring, Inc.														FirstAssist Group Holdings Limited		Vanbreda International NV
Business Acquisition Percentage Of Voting Interests Acquired																		51.00%																			100.00%
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners																		49.00%
Business Acquisition Description Of Acquired Entity																		Finans Emeklilik operates in life insurance, accident insurance and pension product markets.	one of the largest providers of supplemental health insurance products in the U.S.		HealthSpring provides Medicare Advantage coverage in 13 states and the District of Columbia, as well as a large, national stand-alone Medicare prescription drug business. The acquisition of HealthSpring strengthens the Company’s ability to serve individuals across their life stages as well as deepens its presence in a number of geographic markets.														FirstAssist is based in the United Kingdom and provides travel and protection insurance services
Business Combination Reason For Business Combination																		The acquisition provides Cigna opportunities to reach and serve the growing middle class market in Turkey through Finansbank’s network of retail banking branches.	The acquisition provides the Company with an increased presence in the Medicare supplemental benefits market. It also extends the Company’s global direct-to-consumer retail channel as well as further enhances its distribution network of agents and brokers.		The addition of HealthSpring brings industry leading physician partnership capabilities and creates the opportunity to deepen the Company’s existing client and customer relationships, as well as facilitates a broader deployment of its range of health and wellness capabilities and product offerings.														FirstAssist is based in the United Kingdom and provides travel and protection insurance services that the Company expects will enhance its individual business in the U.K. and around the world.		Vanbreda International’s market leadership in the intergovernmental segment complements the Company’s position in providing global health benefits primarily to multinational companies and organizations and their globally mobile employees in North America, Europe, the Middle East and Asia.
Healthspring Medicare Advantage Coverage Number Of States																					13
Minority Interest Redemption Term																		15 years
Business Acquisition, Cost of Acquired Entity, Purchase Price [Abstract]
HealthSpring, Inc. common shares outstanding at January 30, 2012	285,829,000				285,533,000				285,829,000	285,533,000	271,880,000										67,800,000
Less: common shares outstanding not settled in cash																					(100,000)
Common shares settled in cash																					67,700,000
Price per share																					$ 55
Cash consideration for outstanding shares																					$ 3,725																$ 412
Fair value of share-based compensation awards																					65
Additional cash and equity consideration																					21
Total merger consideration																		116	326	19	3,811														115
Business Acquisition Fair Value Of Share Based Compensation Awards [Abstract]
Conversion Ratio Health Spring To Cigna Stock																					1.24
Share Price																					$ 44.43
Expected option life assumption																										4 years 9 months 18 days	1 year 9 months 18 days
Effect Of Rollover Awards For Healthspring Employees [Abstract]
Number of Awards																					2,711,000							589,000	1,336,000	786,000
Average exercise/award price																												$ 14.04	$ 16.21	$ 44.43
Fair value of awards																					90							18	37	35
Included in purchase price																					65							18	28	19
Compensation expense post-acquisition																					25							0	9	16
Business Acquisition Purchase Price Allocation [Abstract]
Business Acquisition Purchase Price Allocation Methodology																			In accordance with GAAP, the total purchase price has been allocated to the tangible and intangible net assets acquired based on management’s preliminary estimates of their fair value and may change as additional information becomes available over the next several months.		In accordance with GAAP, the total pruchase price has been allocated to the tangible and intangible net assets acquired based on management's estimates of their fair values. The fair value of the customer relationship and the amortization method were determined using an income approach that relies on projected future net cash flows including key assumptions for the customer attrition rate and discount rate.																In accordance with GAAP, the total purchase price has been allocated to the tangible and intangible net assets acquired based on management’s estimates of their fair values.
Allocation to the value of business acquired asset																		28	144	73
Allocation to insurance liabilities																		58	707	73	505
Allocation to tax accounts																			(7)	(15)
Allocation to goodwill																		113	168		2,541														64	8
Business Combination Goodwill Recognized Segment Allocation																		Global Supplemental Benefits segment	International Segment Global Supplemental Benefits Segment		Government operating segment														Global Supplemental Benefits
Business Acquisition Purchase Price Allocation Goodwill Expected Tax Deductible Amount Description																			Substantially all of the goodwill is tax deductible and will be amortized over the next 15 years for federal income tax purposes.
Acquired Goodwill Amortization Period For Federal Income Tax Purposes																			15 years
Intangible assets																		117	168		795										711	84			40	(18)	210
Acquired Finite-lived Intangible Asset, Weighted Average Useful Life																		10	30												8		10	3			15
Percent of projected benefits reflected in weighted average useful life assumption for acquired intangible assets																					90.00%
Business Acquisition Period Results Included In Combined Entity																		The results of Finans Emeklilik are included in the Company's Consolidated Financial Statements from the date of acquisition.	The results of this business have been included in the Company's Consolidated Financial Statements from the date of acquisition and were not considered material to the Company's consolidated results of operations.		The results of HealthSpring have been included in the Company's Consolidated Financial Statements from the date of the acquisition.
Revenues included in the Company's results	7,620	7,323	7,422	6,754	5,425	5,574	5,479	5,387	29,119	21,865	21,128			21,875	21,134	(10)	(6)					5,400
Business Combination, Acquisition Related Costs																								53	40
Business Acquisition Pro Forma Information [Abstract]
Total Revenues																						29,608	27,461
Shareholders' net income																						1,633	1,456
Earnings per share:
Basic																						$ 5.73	$ 5.11
Diluted																						$ 5.63	$ 5.02
Pro forma information																						Pro forma information. The following table presents selected unaudited pro forma information for the Company assuming the acquisition of HealthSpring had occurred as of January 1, 2011. This pro forma information does not purport to represent what the Company’s actual results would have been if the acquisition had occurred as of the date indicated or what such results would be for any future periods.
Significant Dispositions [Line Items]
Significant Acquisitions and Disposals, Date of Transaction for Acquisition or Disposal												Dec. 31, 2010
Significant Disposition Description												On December 31, 2010, the Company essentially exited from its workers' compensation and personal accident reinsurance business by purchasing retrocessional coverage from a Bermuda subsidiary of Enstar Group Limited and transferring administration of this business to the reinsurer. Under the reinsurance agreement, Cigna is indemnified for liabilities with respect to its workers’ compensation and personal accident reinsurance business to the extent that these liabilities do not exceed 190% of the December 31, 2010 net reserves. The Company believes that the risk of loss beyond this maximum aggregate is remote.
Significant Acquisitions and Disposals, Type												essentially exited by purchasing retrocessional coverage
Significant Business Dispositions Costs Or Sale Proceeds												190
Significant Business Disposition Gain or Loss, Net Of Tax												(20)
Significant Business Disposition Gain or Loss, PreTax												$ (31)
Significant Acquisitions And Disposals Segment												Run-off Reinsurance segment
Maximum Aggregrate Of Liabilites To Net Reserves													190.00%