Acquisitions (Schedule of recognized identifiable assets acquired and liabilities assumed) (Details) - USD ($) $ in Millions		Dec. 31, 2023	Jul. 01, 2023	Dec. 31, 2022	Jul. 01, 2022	Dec. 31, 2021	Jan. 01, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Accrued investment income		$ 1,086		$ 941
Insurance and reinsurance balances receivable		13,379		11,933
Reinsurance recoverable on losses and loss expenses	[1]	19,952		18,859
Reinsurance recoverable on policy benefits	[1]	280		302
Value of business acquired		3,674		3,702		$ 235		$ 263
Other assets		7,317		7,546
Total assets		230,682		199,017
Unpaid losses and loss expenses		80,122		75,747		72,330		$ 67,192
Unearned premiums		22,051		19,713
Future policy benefits		13,888		10,476		7,837	$ 7,652
Policyholders' account balances		7,462		3,140		2,766
Insurance and reinsurance balances payable		8,302		7,780
Accounts Payable and Accrued Liabilities		8,332		7,148
Deferred tax liabilities		1,555		377
Repurchase agreements		2,833		1,419
Total liabilities		166,991		148,498
Stockholders' Equity		59,507		50,519		58,328
Noncontrolling interests		4,184		0
Total shareholders’ equity		63,691		50,519		$ 58,328
Total liabilities and shareholders’ equity		$ 230,682		$ 199,017
Cigna's Life Insurance Business in Asian Markets
Business Acquisition [Line Items]
Investments and Cash					$ 5,281
Accrued investment income					33
Insurance and reinsurance balances receivable					52
Reinsurance recoverable on losses and loss expenses					3
Reinsurance recoverable on policy benefits					85
Value of business acquired					3,633
Goodwill and intangible assets					1,498
Other assets					651
Total assets					11,236
Unpaid losses and loss expenses					12
Unearned premiums					61
Future policy benefits					3,856
Insurance and reinsurance balances payable					115
Accounts Payable and Accrued Liabilities					925
Deferred tax liabilities					887
Repurchase agreements					2,000
Total liabilities					5,856
Stockholders' Equity					5,380
Total liabilities and shareholders’ equity					$ 11,236
Huatai Group [Member]
Business Acquisition [Line Items]
Investments and Cash			$ 13,346
Accrued investment income			60
Insurance and reinsurance balances receivable			277
Reinsurance recoverable on losses and loss expenses			581
Reinsurance recoverable on policy benefits			27
Value of business acquired			309
Goodwill and intangible assets			5,049
Other assets			748
Total assets			20,397
Unpaid losses and loss expenses			831
Unearned premiums			800
Future policy benefits			2,287
Policyholders' account balances			4,014
Insurance and reinsurance balances payable			644
Accounts Payable and Accrued Liabilities			682
Deferred tax liabilities			232
Repurchase agreements			1,269
Total liabilities			10,759
Stockholders' Equity			4,428
Noncontrolling interests			5,210
Total shareholders’ equity			$ 9,638

[1] Net of valuation allowance for uncollectible reinsurance.