Investments (Continuous Gross Unrealized Losses for Fixed Maturity Securities by Sector) (Details) $ in Millions	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities in continuous unrealized loss position, less than 12 months, estimated fair value	$ 11,643	$ 7,973
Fixed maturity securities in continuous unrealized loss position, less than 12 months, gross unrealized losses	$ 690	$ 585
Fixed maturity securities in continuous unrealized loss position, less than 12 months, number of securities	1,815	1,339
Fixed maturity securities in continuous unrealized loss position, 12 months or greater, estimated fair value	$ 48,713	$ 51,190
Fixed maturity securities in continuous unrealized loss position, 12 months or greater, gross unrealized losses	$ 6,973	$ 6,462
Fixed maturity securities in continuous unrealized loss position, 12 months or greater, number of securities	6,634	6,958
U.S. corporate
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities in continuous unrealized loss position, less than 12 months, estimated fair value	$ 6,082	$ 4,549
Fixed maturity securities in continuous unrealized loss position, less than 12 months, gross unrealized losses	479	409
Fixed maturity securities in continuous unrealized loss position, 12 months or greater, estimated fair value	22,112	22,435
Fixed maturity securities in continuous unrealized loss position, 12 months or greater, gross unrealized losses	3,224	2,923
Foreign corporate
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities in continuous unrealized loss position, less than 12 months, estimated fair value	1,684	1,010
Fixed maturity securities in continuous unrealized loss position, less than 12 months, gross unrealized losses	87	74
Fixed maturity securities in continuous unrealized loss position, 12 months or greater, estimated fair value	8,032	8,229
Fixed maturity securities in continuous unrealized loss position, 12 months or greater, gross unrealized losses	1,320	1,202
U.S. government and agency
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities in continuous unrealized loss position, less than 12 months, estimated fair value	1,103	445
Fixed maturity securities in continuous unrealized loss position, less than 12 months, gross unrealized losses	28	8
Fixed maturity securities in continuous unrealized loss position, 12 months or greater, estimated fair value	2,878	3,453
Fixed maturity securities in continuous unrealized loss position, 12 months or greater, gross unrealized losses	550	509
RMBS
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities in continuous unrealized loss position, less than 12 months, estimated fair value	708	413
Fixed maturity securities in continuous unrealized loss position, less than 12 months, gross unrealized losses	21	21
Fixed maturity securities in continuous unrealized loss position, 12 months or greater, estimated fair value	5,591	5,749
Fixed maturity securities in continuous unrealized loss position, 12 months or greater, gross unrealized losses	885	784
ABS
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities in continuous unrealized loss position, less than 12 months, estimated fair value	1,057	572
Fixed maturity securities in continuous unrealized loss position, less than 12 months, gross unrealized losses	6	3
Fixed maturity securities in continuous unrealized loss position, 12 months or greater, estimated fair value	2,106	3,355
Fixed maturity securities in continuous unrealized loss position, 12 months or greater, gross unrealized losses	102	128
CMBS
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities in continuous unrealized loss position, less than 12 months, estimated fair value	367	411
Fixed maturity securities in continuous unrealized loss position, less than 12 months, gross unrealized losses	28	33
Fixed maturity securities in continuous unrealized loss position, 12 months or greater, estimated fair value	5,687	5,713
Fixed maturity securities in continuous unrealized loss position, 12 months or greater, gross unrealized losses	514	568
State and political subdivision
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities in continuous unrealized loss position, less than 12 months, estimated fair value	581	460
Fixed maturity securities in continuous unrealized loss position, less than 12 months, gross unrealized losses	40	31
Fixed maturity securities in continuous unrealized loss position, 12 months or greater, estimated fair value	1,641	1,636
Fixed maturity securities in continuous unrealized loss position, 12 months or greater, gross unrealized losses	280	267
Foreign Government
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities in continuous unrealized loss position, less than 12 months, estimated fair value	61	113
Fixed maturity securities in continuous unrealized loss position, less than 12 months, gross unrealized losses	1	6
Fixed maturity securities in continuous unrealized loss position, 12 months or greater, estimated fair value	666	620
Fixed maturity securities in continuous unrealized loss position, 12 months or greater, gross unrealized losses	$ 98	$ 81