Investments (Fixed Maturity Securities by Sector) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, amortized cost	$ 87,277	$ 86,129
Fixed maturity securities, allowance for credit losses	43	21	$ 11	$ 6
Fixed maturity securities, gross unrealized gains	562	1,024
Fixed maturity securities, gross unrealized losses	7,998	7,047
Fixed maturity securities, estimated fair value	79,798	80,085
U.S. corporate
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, amortized cost	39,486	38,303
Fixed maturity securities, allowance for credit losses	31	15	4	1
Fixed maturity securities, gross unrealized gains	220	383
Fixed maturity securities, gross unrealized losses	3,903	3,332
Fixed maturity securities, estimated fair value	35,772	35,339
Foreign corporate
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, amortized cost	13,368	12,769
Fixed maturity securities, allowance for credit losses	4	0	0	1
Fixed maturity securities, gross unrealized gains	47	89
Fixed maturity securities, gross unrealized losses	1,480	1,276
Fixed maturity securities, estimated fair value	11,931	11,582
U.S. government and agency
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, amortized cost	7,624	8,446
Fixed maturity securities, allowance for credit losses	0	0
Fixed maturity securities, gross unrealized gains	97	285
Fixed maturity securities, gross unrealized losses	614	517
Fixed maturity securities, estimated fair value	7,107	8,214
Residential mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, amortized cost	8,623	8,127
Fixed maturity securities, allowance for credit losses	5	4	4	1
Fixed maturity securities, gross unrealized gains	42	48
Fixed maturity securities, gross unrealized losses	926	805
Fixed maturity securities, estimated fair value	7,734	7,366
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, amortized cost	6,526	6,509
Fixed maturity securities, allowance for credit losses	0	0
Fixed maturity securities, gross unrealized gains	28	23
Fixed maturity securities, gross unrealized losses	97	131
Fixed maturity securities, estimated fair value	6,457	6,401
Commercial mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, amortized cost	6,843	6,940
Fixed maturity securities, allowance for credit losses	3	2	$ 3	$ 3
Fixed maturity securities, gross unrealized gains	3	2
Fixed maturity securities, gross unrealized losses	526	601
Fixed maturity securities, estimated fair value	6,317	6,339
State and political subdivision
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, amortized cost	3,752	3,958
Fixed maturity securities, allowance for credit losses	0	0
Fixed maturity securities, gross unrealized gains	97	153
Fixed maturity securities, gross unrealized losses	350	298
Fixed maturity securities, estimated fair value	3,499	3,813
Foreign government
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, amortized cost	1,055	1,077
Fixed maturity securities, allowance for credit losses	0	0
Fixed maturity securities, gross unrealized gains	28	41
Fixed maturity securities, gross unrealized losses	102	87
Fixed maturity securities, estimated fair value	$ 981	$ 1,031

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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