Acquisitions and Disposition - Other (Details) (USD $)	3 Months Ended		0 Months Ended		1 Months Ended	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Nov. 09, 2012 Finans Emeklilik [Member]	Aug. 31, 2012 Great American Supplemental Benefits Group [Member]	Jan. 31, 2012 HealthSpring [Member]	Mar. 31, 2012 HealthSpring [Member]
Business Acquisition, Entity Acquired and Reason for Acquisition [Abstract]
Business Acquisition Effective Date Of Acquisition			Nov. 09, 2012	Aug. 31, 2012	Jan. 31, 2012
Business Acquisition Name Of Acquired Entity			Finans Emeklilik ve Hayat A.S.	Great American Supplemental Benefits Group	HealthSpring, Inc.
Business Acquisition Percentage Of Voting Interests Acquired			51.00%
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
Business Combination Reason For Business Combination			The acquisition will provide 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. Results of this business are reported in the supplemental health, life and accident business included in the International segment.
Healthspring Medicare Advantage Coverage Number Of States					15
Minority Interest Redemption Term			15 years
Business Acquisition Share Price					$ 55
Total merger consideration					$ 3,800,000,000
Business Acquisition Purchase Price Allocation [Abstract]
Allocation to the value of business acquired asset			26,000,000	144,000,000
Allocation to insurance liabilities			58,000,000	707,000,000	505,000,000
Allocation to goodwill			116,000,000	168,000,000	2,541,000,000
Business Combination Goodwill Recognized Segment Allocation			Global Supplemental Benefits Segment	Global Supplemental Benefits Segment
Acquired Goodwill Amortization Period For Federal Income Tax Purposes				15 years
Intangible assets			113,000,000	168,000,000	795,000,000
Acquired Finite-lived Intangible Asset, Weighted Average Useful Life			10 years	30 years
Revenues included in the Company's results	8,183,000,000	6,754,000,000				1,000,000,000
Business Acquisition Pro Forma Information [Abstract]
Total Revenues						7,277,000,000
Shareholders' net income						$ 381,000,000
Earnings per share:
Basic						$ 1.33
Diluted						$ 1.32