General (Effects of Adoption ASU 2018-12, Segment Results) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022		Dec. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net incurred claims and benefits	$ 1,772	$ 1,594	$ 3,418	$ 3,066
Core income (loss) before income tax	393	286	799	652
Income tax (expense) benefit on core income (loss)	(85)	(56)	(166)	(124)
Core income (loss)	308	230	633	528
Claim and claim adjustment expenses	22,802		22,802		$ 22,120	[1]
Future policy benefits	13,666	14,157	13,666	14,157	13,480	[1]	$ 19,132
Life & Group | Operating Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net incurred claims and benefits	344	311	655	615
Core income (loss) before income tax	(33)	(22)	(45)	(29)
Income tax (expense) benefit on core income (loss)	13	13	22	25
Core income (loss)	(20)	(9)	(23)	(4)
Claim and claim adjustment expenses	688		688		695
Future policy benefits	$ 13,666		$ 13,666		13,480
Prior to Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Claim and claim adjustment expenses					25,099
Future policy benefits					10,151		$ 13,318
Prior to Adoption | Life & Group | Operating Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net incurred claims and benefits		293		574
Core income (loss) before income tax		(4)		12
Income tax (expense) benefit on core income (loss)		10		17
Core income (loss)		6		29
Claim and claim adjustment expenses					3,674
Future policy benefits					10,151
Effect of Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Claim and claim adjustment expenses					(2,979)
Future policy benefits					3,329
Effect of Adoption | Life & Group | Operating Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net incurred claims and benefits		18		41
Core income (loss) before income tax		(18)		(41)
Income tax (expense) benefit on core income (loss)		3		8
Core income (loss)		$ (15)		$ (33)
Claim and claim adjustment expenses					(2,979)
Future policy benefits					$ 3,329

[1] As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Condensed Consolidated Financial Statements for additional information.