Fair Value Measurements - Changes in balances of Level 3 financial assets carried at fair value (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Jun. 30, 2022	Dec. 31, 2021	Dec. 31, 2020
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Financial assets, Beginning Balance	$ 983	$ 865	$ 926	$ 3,706
Total realized/unrealized gains (losses) included in Net income	(4)	5	18	161
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	(20)	(1)	(53)	(23)
Purchases and issuances	74	98	243	535
Sales and settlements	(29)	(52)	(88)	(496)
Transfer into Level 3	4	10	43	66
Transfer out of Level 3	(6)	(27)	(87)	(332)
Sale of annuity business				(2,719)
Financial assets, Ending Balance	1,002	898	1,002	898
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value	(25)	0	(25)	0	$ (23)	$ (23)	$ (3,933)
Contingent consideration — acquisitions
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value	(25)		(25)		$ (23)	$ (23)
Fixed maturities
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Financial assets, Beginning Balance	593	605	600	538
Total realized/unrealized gains (losses) included in Net income	(1)	0	1	(3)
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	(20)	(1)	(53)	(2)
Purchases and issuances	50	77	167	279
Sales and settlements	(14)	(48)	(68)	(145)
Transfer into Level 3	4	10	40	33
Transfer out of Level 3	(5)	(25)	(80)	(82)
Sale of annuity business				0
Financial assets, Ending Balance	607	618	607	618
U.S. government agency
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Financial assets, Beginning Balance	0	0	0	0
Total realized/unrealized gains (losses) included in Net income	0	0	0	0
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	0	0	0	0
Purchases and issuances	0	0	0	0
Sales and settlements	0	0	0	0
Transfer into Level 3	0	0	0	0
Transfer out of Level 3	0	0	0	0
Sale of annuity business				0
Financial assets, Ending Balance	0	0	0	0
State and municipal
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Financial assets, Beginning Balance	1	36	41	39
Total realized/unrealized gains (losses) included in Net income	0	0	0	0
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	0	0	(3)	0
Purchases and issuances	0	0	0	0
Sales and settlements	0	0	(1)	(3)
Transfer into Level 3	0	8	0	8
Transfer out of Level 3	0	(2)	(36)	(2)
Sale of annuity business				0
Financial assets, Ending Balance	1	42	1	42
Residential MBS
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Financial assets, Beginning Balance	8	28	14	38
Total realized/unrealized gains (losses) included in Net income	0	(1)	0	(4)
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	0	0	0	0
Purchases and issuances	0	0	0	6
Sales and settlements	0	(1)	(1)	(2)
Transfer into Level 3	4	0	4	6
Transfer out of Level 3	(4)	(8)	(9)	(26)
Sale of annuity business				0
Financial assets, Ending Balance	8	18	8	18
Commercial MBS
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Financial assets, Beginning Balance	0	0	0	2
Total realized/unrealized gains (losses) included in Net income	0	0	0	0
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	0	0	0	0
Purchases and issuances	0	0	0	0
Sales and settlements	0	0	0	0
Transfer into Level 3	0	0	0	0
Transfer out of Level 3	0	0	0	(2)
Sale of annuity business				0
Financial assets, Ending Balance	0	0	0	0
Collateralized loan obligations
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Financial assets, Beginning Balance	2	6	0	16
Total realized/unrealized gains (losses) included in Net income	0	0	0	1
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	0	1	0	0
Purchases and issuances	0	0	0	0
Sales and settlements	0	0	0	(1)
Transfer into Level 3	0	0	2	0
Transfer out of Level 3	0	(6)	0	(15)
Sale of annuity business				0
Financial assets, Ending Balance	2	1	2	1
Other asset-backed securities
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Financial assets, Beginning Balance	313	315	278	305
Total realized/unrealized gains (losses) included in Net income	0	1	2	1
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	(8)	(1)	(24)	0
Purchases and issuances	5	41	62	131
Sales and settlements	(9)	(38)	(51)	(110)
Transfer into Level 3	0	0	34	14
Transfer out of Level 3	0	(9)	0	(32)
Sale of annuity business				0
Financial assets, Ending Balance	301	309	301	309
Corporate and other
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Financial assets, Beginning Balance	269	220	267	138
Total realized/unrealized gains (losses) included in Net income	(1)	0	(1)	(1)
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	(12)	(1)	(26)	(2)
Purchases and issuances	45	36	105	142
Sales and settlements	(5)	(9)	(15)	(29)
Transfer into Level 3	0	2	0	5
Transfer out of Level 3	(1)	0	(35)	(5)
Sale of annuity business				0
Financial assets, Ending Balance	295	248	295	248
Equity securities
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Financial assets, Beginning Balance	378	245	313	176
Total realized/unrealized gains (losses) included in Net income	(2)	7	20	78
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	0	0	0	0
Purchases and issuances	24	20	75	44
Sales and settlements	(15)	(4)	(20)	(23)
Transfer into Level 3	0	0	3	0
Transfer out of Level 3	(1)	0	(7)	(7)
Sale of annuity business				0
Financial assets, Ending Balance	384	268	384	268
Assets of MIE
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Financial assets, Beginning Balance	12	15	13	21
Total realized/unrealized gains (losses) included in Net income	(1)	(2)	(3)	1
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	0	0	0	0
Purchases and issuances	0	1	1	3
Sales and settlements	0	0	0	0
Transfer into Level 3	0	0	0	1
Transfer out of Level 3	0	(2)	0	(14)
Sale of annuity business				0
Financial assets, Ending Balance	$ 11	12	$ 11	12
Assets of discontinued annuity operations | Annuity subsidiaries
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Financial assets, Beginning Balance				2,971
Total realized/unrealized gains (losses) included in Net income				85
Total realized/unrealized gains (losses) included in other comprehensive income (loss)				(21)
Purchases and issuances				209
Sales and settlements				(328)
Transfer into Level 3				32
Transfer out of Level 3				(229)
Sale of annuity business				(2,719)
Financial assets, Ending Balance		$ 0		$ 0