Fair Value Measurements - Assets and liabilities measured and carried at fair value in the financial statements (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Assets:
Available for sale (AFS) fixed maturities	$ 10,044	$ 10,095
Trading fixed maturities	36	32
Equity securities	1,008	1,010
Assets of managed investment entities	28,481	28,831
Derivative asset	44	40
Total assets accounted for at fair value	16,483	16,584
Liabilities:
Liabilities of managed investment entities	24,540	24,779
Derivative liability	28	42
Total liabilities accounted for at fair value	5,311	5,399
Contingent consideration — acquisitions
Liabilities:
Fair value of potential contingent consideration	25	25
Other liabilities — derivatives
Liabilities:
Derivative liability	28	42
Variable interest entity, primary beneficiary
Assets:
Assets of managed investment entities	5,391	5,447
Liabilities:
Liabilities of managed investment entities	5,258	5,332
Fixed maturities
Assets:
Available for sale (AFS) fixed maturities	10,044	10,095
Trading fixed maturities	36	32
U.S. government and government agencies
Assets:
Available for sale (AFS) fixed maturities	225	219
States, municipalities and political subdivisions
Assets:
Available for sale (AFS) fixed maturities	993	1,186
Foreign government
Assets:
Available for sale (AFS) fixed maturities	226	226
Residential MBS
Assets:
Available for sale (AFS) fixed maturities	1,589	1,598
Commercial MBS
Assets:
Available for sale (AFS) fixed maturities	78	85
Collateralized loan obligations
Assets:
Available for sale (AFS) fixed maturities	1,899	1,921
Other asset-backed securities
Assets:
Available for sale (AFS) fixed maturities	2,241	2,245
Corporate and other
Assets:
Available for sale (AFS) fixed maturities	2,793	2,615
Equity securities
Assets:
Equity securities	1,008	1,010
Other assets
Assets:
Derivative asset	4
Level 1
Assets:
Total assets accounted for at fair value	1,278	1,442
Liabilities:
Total liabilities accounted for at fair value	465	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	477	659
Liabilities:
Liabilities of managed investment entities	465	645
Level 1 | Fixed maturities
Assets:
Available for sale (AFS) fixed maturities	233	227
Trading fixed maturities	0	0
Level 1 | U.S. government and government agencies
Assets:
Available for sale (AFS) fixed maturities	225	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	8	8
Level 1 | Equity securities
Assets:
Equity securities	568	556
Level 1 | Other assets
Assets:
Derivative asset	0
Level 2
Assets:
Total assets accounted for at fair value	14,077	14,040
Liabilities:
Total liabilities accounted for at fair value	4,809	4,718
Level 2 | Contingent consideration — acquisitions
Liabilities:
Fair value of potential contingent consideration	0	0
Level 2 | Other liabilities — derivatives
Liabilities:
Derivative liability	28	42
Level 2 | Variable interest entity, primary beneficiary
Assets:
Assets of managed investment entities	4,902	4,777
Liabilities:
Liabilities of managed investment entities	4,781	4,676
Level 2 | Fixed maturities
Assets:
Available for sale (AFS) fixed maturities	9,106	9,204
Trading fixed maturities	36	32
Level 2 | U.S. government and government agencies
Assets:
Available for sale (AFS) fixed maturities	0	0
Level 2 | States, municipalities and political subdivisions
Assets:
Available for sale (AFS) fixed maturities	988	1,181
Level 2 | Foreign government
Assets:
Available for sale (AFS) fixed maturities	226	226
Level 2 | Residential MBS
Assets:
Available for sale (AFS) fixed maturities	1,584	1,589
Level 2 | Commercial MBS
Assets:
Available for sale (AFS) fixed maturities	78	85
Level 2 | Collateralized loan obligations
Assets:
Available for sale (AFS) fixed maturities	1,898	1,919
Level 2 | Other asset-backed securities
Assets:
Available for sale (AFS) fixed maturities	1,906	1,916
Level 2 | Corporate and other
Assets:
Available for sale (AFS) fixed maturities	2,426	2,288
Level 2 | Equity securities
Assets:
Equity securities	29	27
Level 2 | Other assets
Assets:
Derivative asset	4
Level 3
Assets:
Total assets accounted for at fair value	1,128	1,102
Liabilities:
Total liabilities accounted for at fair value	37	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	12	11
Liabilities:
Liabilities of managed investment entities	12	11
Level 3 | Fixed maturities
Assets:
Available for sale (AFS) fixed maturities	705	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	335	329
Level 3 | Corporate and other
Assets:
Available for sale (AFS) fixed maturities	359	319
Level 3 | Equity securities
Assets:
Equity securities	411	$ 427
Level 3 | Other assets
Assets:
Derivative asset	$ 0