Acquisitions and Disposition - Other (Details) (USD $)	3 Months Ended		6 Months Ended		0 Months Ended		1 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Nov. 09, 2012 Finans Emeklilik [Member]	Aug. 31, 2012 Great American Supplemental Benefits Group [Member]	Jan. 31, 2012 HealthSpring [Member]	Jun. 30, 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.	HealthSpring provides Medicare Advantage coverage in 15 states and the District of Columbia, as well as a large, national stand-alone Medicare prescription drug business.
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 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. 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.
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]
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	7,980,000,000	7,422,000,000	16,163,000,000	14,176,000,000				2,500,000,000
Business Acquisition Pro Forma Information [Abstract]
Total Revenues								14,734,000,000
Shareholders' net income								$ 761,000,000
Earnings per share:
Basic								$ 2.66
Diluted								$ 2.62