Acquisitions (Narrative) (Details) - USD ($) $ in Millions				3 Months Ended	12 Months Ended
	May 31, 2024	Jul. 01, 2023	Jul. 01, 2022	Mar. 31, 2024	Dec. 31, 2024		Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Goodwill					$ 19,579	[1]	$ 19,686		$ 16,228
Other intangible assets					6,377		6,775
Value of business acquired					3,223		3,674		$ 3,702	$ 235
Repurchase agreements					$ 2,731		$ 2,833
Huatai Group [Member]
Business Acquisition [Line Items]
Subsidiary, Ownership Percentage, Parent		69.60%			85.50%		76.50%
Additional 9.0 percent ownership interest obtained in subsidiary				9.00%
Outstanding 1.6 percent additional ownership interest agreed on					1.60%
Additional 1.0 percent interest agreed on					1.00%
Huatai Group [Member]
Business Acquisition [Line Items]
Ownership Percentage								64.20%
Cigna's Life Insurance Business in Asian Markets
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition			Jul. 01, 2022
Payments to Acquire Businesses, Gross			$ 5,400
Huatai Group [Member]
Business Acquisition [Line Items]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Fair Value		$ 4,100
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain		763
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Loss		17
Write-off of Accumulated AOCI Loss Balance, Equity Method Invesmtent		611
Business combination, Realized Gain (Loss) from Write-off of AOCI in Equity Method Investment		(628)
Deposits previously paid on additional ownership interest obtained				$ 555
Goodwill		3,458
Other intangible assets		1,655
Value of business acquired		$ 309
Business Acquisition, Effective Date of Acquisition		Jul. 01, 2023
Repurchase agreements		$ 1,269
Deposits previously paid on ownership obtained				$ 319
Payments to Acquire Additional Interest in Subsidiaries					$ 236
Healthy Paws
Business Acquisition [Line Items]
Goodwill	$ 256
Other intangible assets	$ 44
Business Acquisition, Effective Date of Acquisition	May 31, 2024
Payments to Acquire Businesses, Gross	$ 300

[1] Includes $499 million attributable to noncontrolling interests