Fair Value Measurements - Assets and liabilities measured and carried at fair value in the financial statements (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Assets:
Available for sale (AFS) fixed maturities	$ 9,793	$ 10,357
Trading fixed maturities	29	28
Equity securities	1,029	1,042
Assets of managed investment entities	28,084	28,931
Total assets accounted for at fair value	16,070	16,723
Liabilities:
Liabilities of managed investment entities	24,017	23,919
Total liabilities accounted for at fair value	5,169	5,243
Contingent consideration — acquisitions
Liabilities:
Contingent consideration	23	23
Other liabilities — derivatives
Liabilities:
Derivative liability	13
Variable interest entity, primary beneficiary
Assets:
Assets of managed investment entities	5,218	5,296
Liabilities:
Liabilities of managed investment entities	5,133	5,220
Fixed maturities
Assets:
Available for sale (AFS) fixed maturities	9,793	10,357
Trading fixed maturities	29	28
U.S. Government and government agencies
Assets:
Available for sale (AFS) fixed maturities	216	216
States, municipalities and political subdivisions
Assets:
Available for sale (AFS) fixed maturities	1,402	1,832
Foreign government
Assets:
Available for sale (AFS) fixed maturities	246	246
Residential MBS
Assets:
Available for sale (AFS) fixed maturities	1,555	960
Commercial MBS
Assets:
Available for sale (AFS) fixed maturities	92	104
Collateralized loan obligations
Assets:
Available for sale (AFS) fixed maturities	1,607	1,643
Other asset-backed securities
Assets:
Available for sale (AFS) fixed maturities	2,258	2,676
Corporate and other
Assets:
Available for sale (AFS) fixed maturities	2,417	2,680
Equity securities
Assets:
Equity securities	1,029	1,042
Other assets
Liabilities:
Derivative asset	1
Level 1
Assets:
Total assets accounted for at fair value	1,178	1,295
Liabilities:
Total liabilities accounted for at fair value	339	384
Level 1 | Contingent consideration — acquisitions
Liabilities:
Contingent consideration	0	0
Level 1 | Other liabilities — derivatives
Liabilities:
Derivative liability	0
Level 1 | Variable interest entity, primary beneficiary
Assets:
Assets of managed investment entities	344	390
Liabilities:
Liabilities of managed investment entities	339	384
Level 1 | Fixed maturities
Assets:
Available for sale (AFS) fixed maturities	225	226
Trading fixed maturities	0	0
Level 1 | U.S. Government and government agencies
Assets:
Available for sale (AFS) fixed maturities	215	215
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	10	11
Level 1 | Equity securities
Assets:
Equity securities	609	679
Level 1 | Other assets
Liabilities:
Derivative asset	0
Level 2
Assets:
Total assets accounted for at fair value	13,909	14,502
Liabilities:
Total liabilities accounted for at fair value	4,796	4,823
Level 2 | Contingent consideration — acquisitions
Liabilities:
Contingent consideration	0	0
Level 2 | Other liabilities — derivatives
Liabilities:
Derivative liability	13
Level 2 | Variable interest entity, primary beneficiary
Assets:
Assets of managed investment entities	4,862	4,893
Liabilities:
Liabilities of managed investment entities	4,783	4,823
Level 2 | Fixed maturities
Assets:
Available for sale (AFS) fixed maturities	8,975	9,531
Trading fixed maturities	29	28
Level 2 | U.S. Government and government agencies
Assets:
Available for sale (AFS) fixed maturities	1	1
Level 2 | States, municipalities and political subdivisions
Assets:
Available for sale (AFS) fixed maturities	1,401	1,791
Level 2 | Foreign government
Assets:
Available for sale (AFS) fixed maturities	246	246
Level 2 | Residential MBS
Assets:
Available for sale (AFS) fixed maturities	1,547	946
Level 2 | Commercial MBS
Assets:
Available for sale (AFS) fixed maturities	92	104
Level 2 | Collateralized loan obligations
Assets:
Available for sale (AFS) fixed maturities	1,605	1,643
Level 2 | Other asset-backed securities
Assets:
Available for sale (AFS) fixed maturities	1,945	2,398
Level 2 | Corporate and other
Assets:
Available for sale (AFS) fixed maturities	2,138	2,402
Level 2 | Equity securities
Assets:
Equity securities	42	50
Level 2 | Other assets
Liabilities:
Derivative asset	1
Level 3
Assets:
Total assets accounted for at fair value	983	926
Liabilities:
Total liabilities accounted for at fair value	34	36
Level 3 | Contingent consideration — acquisitions
Liabilities:
Contingent consideration	23	23
Level 3 | Other liabilities — derivatives
Liabilities:
Derivative liability	0
Level 3 | Variable interest entity, primary beneficiary
Assets:
Assets of managed investment entities	12	13
Liabilities:
Liabilities of managed investment entities	11	13
Level 3 | Fixed maturities
Assets:
Available for sale (AFS) fixed maturities	593	600
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	1	41
Level 3 | Foreign government
Assets:
Available for sale (AFS) fixed maturities	0	0
Level 3 | Residential MBS
Assets:
Available for sale (AFS) fixed maturities	8	14
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	2	0
Level 3 | Other asset-backed securities
Assets:
Available for sale (AFS) fixed maturities	313	278
Level 3 | Corporate and other
Assets:
Available for sale (AFS) fixed maturities	269	267
Level 3 | Equity securities
Assets:
Equity securities	378	$ 313
Level 3 | Other assets
Liabilities:
Derivative asset	$ 0