Fair Value Measurements - Assets and liabilities measured and carried at fair value in the financial statements (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Assets:
Available for sale (AFS) fixed maturities	$ 9,885	$ 10,095
Trading fixed maturities	38	32
Equity securities	1,048	1,010
Assets of managed investment entities	29,048	28,831
Derivative asset	96	40
Total assets accounted for at fair value	16,210	16,584
Liabilities:
Liabilities of managed investment entities	25,055	24,779
Derivative liability	41	42
Total liabilities accounted for at fair value	5,164	5,399
Contingent consideration — acquisitions
Liabilities:
Fair value of potential contingent consideration	25	25
Other liabilities — derivatives
Liabilities:
Derivative liability	41	42
Variable interest entity, primary beneficiary
Assets:
Assets of managed investment entities	5,235	5,447
Liabilities:
Liabilities of managed investment entities	5,098	5,332
Fixed maturities:
Assets:
Available for sale (AFS) fixed maturities	9,885	10,095
Trading fixed maturities	38	32
U.S. government and government agencies
Assets:
Available for sale (AFS) fixed maturities	229	219
States, municipalities and political subdivisions
Assets:
Available for sale (AFS) fixed maturities	968	1,186
Foreign government
Assets:
Available for sale (AFS) fixed maturities	228	226
Residential MBS
Assets:
Available for sale (AFS) fixed maturities	1,546	1,598
Commercial MBS
Assets:
Available for sale (AFS) fixed maturities	79	85
Collateralized loan obligations
Assets:
Available for sale (AFS) fixed maturities	1,859	1,921
Other asset-backed securities
Assets:
Available for sale (AFS) fixed maturities	2,169	2,245
Corporate and other
Assets:
Available for sale (AFS) fixed maturities	2,807	2,615
Equity securities
Assets:
Equity securities	1,048	1,010
Other assets
Assets:
Derivative asset	4
Level 1
Assets:
Total assets accounted for at fair value	1,396	1,442
Liabilities:
Total liabilities accounted for at fair value	577	645
Level 1 | Contingent consideration — acquisitions
Liabilities:
Fair value of potential contingent consideration	0	0
Level 1 | Other liabilities — derivatives
Liabilities:
Derivative liability	0	0
Level 1 | Variable interest entity, primary beneficiary
Assets:
Assets of managed investment entities	593	659
Liabilities:
Liabilities of managed investment entities	577	645
Level 1 | Fixed maturities:
Assets:
Available for sale (AFS) fixed maturities	237	227
Trading fixed maturities	0	0
Level 1 | U.S. government and government agencies
Assets:
Available for sale (AFS) fixed maturities	228	219
Level 1 | States, municipalities and political subdivisions
Assets:
Available for sale (AFS) fixed maturities	0	0
Level 1 | Foreign government
Assets:
Available for sale (AFS) fixed maturities	0	0
Level 1 | Residential MBS
Assets:
Available for sale (AFS) fixed maturities	0	0
Level 1 | Commercial MBS
Assets:
Available for sale (AFS) fixed maturities	0	0
Level 1 | Collateralized loan obligations
Assets:
Available for sale (AFS) fixed maturities	0	0
Level 1 | Other asset-backed securities
Assets:
Available for sale (AFS) fixed maturities	0	0
Level 1 | Corporate and other
Assets:
Available for sale (AFS) fixed maturities	9	8
Level 1 | Equity securities
Assets:
Equity securities	566	556
Level 1 | Other assets
Assets:
Derivative asset	0
Level 2
Assets:
Total assets accounted for at fair value	13,654	14,040
Liabilities:
Total liabilities accounted for at fair value	4,551	4,718
Level 2 | Contingent consideration — acquisitions
Liabilities:
Fair value of potential contingent consideration	0	0
Level 2 | Other liabilities — derivatives
Liabilities:
Derivative liability	41	42
Level 2 | Variable interest entity, primary beneficiary
Assets:
Assets of managed investment entities	4,631	4,777
Liabilities:
Liabilities of managed investment entities	4,510	4,676
Level 2 | Fixed maturities:
Assets:
Available for sale (AFS) fixed maturities	8,947	9,204
Trading fixed maturities	38	32
Level 2 | U.S. government and government agencies
Assets:
Available for sale (AFS) fixed maturities	1	0
Level 2 | States, municipalities and political subdivisions
Assets:
Available for sale (AFS) fixed maturities	963	1,181
Level 2 | Foreign government
Assets:
Available for sale (AFS) fixed maturities	228	226
Level 2 | Residential MBS
Assets:
Available for sale (AFS) fixed maturities	1,541	1,589
Level 2 | Commercial MBS
Assets:
Available for sale (AFS) fixed maturities	79	85
Level 2 | Collateralized loan obligations
Assets:
Available for sale (AFS) fixed maturities	1,858	1,919
Level 2 | Other asset-backed securities
Assets:
Available for sale (AFS) fixed maturities	1,848	1,916
Level 2 | Corporate and other
Assets:
Available for sale (AFS) fixed maturities	2,429	2,288
Level 2 | Equity securities
Assets:
Equity securities	34	27
Level 2 | Other assets
Assets:
Derivative asset	4
Level 3
Assets:
Total assets accounted for at fair value	1,160	1,102
Liabilities:
Total liabilities accounted for at fair value	36	36
Level 3 | Contingent consideration — acquisitions
Liabilities:
Fair value of potential contingent consideration	25	25
Level 3 | Other liabilities — derivatives
Liabilities:
Derivative liability	0	0
Level 3 | Variable interest entity, primary beneficiary
Assets:
Assets of managed investment entities	11	11
Liabilities:
Liabilities of managed investment entities	11	11
Level 3 | Fixed maturities:
Assets:
Available for sale (AFS) fixed maturities	701	664
Trading fixed maturities	0	0
Level 3 | U.S. government and government agencies
Assets:
Available for sale (AFS) fixed maturities	0	0
Level 3 | States, municipalities and political subdivisions
Assets:
Available for sale (AFS) fixed maturities	5	5
Level 3 | Foreign government
Assets:
Available for sale (AFS) fixed maturities	0	0
Level 3 | Residential MBS
Assets:
Available for sale (AFS) fixed maturities	5	9
Level 3 | Commercial MBS
Assets:
Available for sale (AFS) fixed maturities	0	0
Level 3 | Collateralized loan obligations
Assets:
Available for sale (AFS) fixed maturities	1	2
Level 3 | Other asset-backed securities
Assets:
Available for sale (AFS) fixed maturities	321	329
Level 3 | Corporate and other
Assets:
Available for sale (AFS) fixed maturities	369	319
Level 3 | Equity securities
Assets:
Equity securities	448	$ 427
Level 3 | Other assets
Assets:
Derivative asset	$ 0