Quarterly Results of Operations (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Selected Quarterly Financial Information [Abstract]
Revenues	$ 5,241	$ 5,651	$ 4,878	$ 6,337	$ 5,007	$ 5,153	$ 4,156	$ 4,251	$ 22,107	$ 18,567	$ 16,227
Total benefits and expenses	5,016	5,437	4,609	6,065	4,843	4,773	3,891	3,900	21,127	17,407	15,509
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	225	214	269	272	164	380	265	351	980	1,160	718
Net Income	$ 150	$ 158	$ 204	$ 212	$ 160	$ 289	$ 207	$ 253	$ 724	$ 909	$ 521
Earnings Per Share, Diluted [Abstract]
Diluted earnings per share	$ 2.22	$ 2.33	$ 3.03	$ 3.16	$ 2.37	$ 4.29	$ 3.05	$ 3.72	$ 10.73	$ 13.44	$ 7.64
Basic earnings per share:
Basic earnings per share	$ 2.26	$ 2.37	$ 3.07	$ 3.20	$ 2.40	$ 4.34	$ 3.09	$ 3.77	$ 10.90	$ 13.60	$ 7.73