Consolidated Statements of Operations - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues
Earned premiums									$ 21,026	$ 19,390	$ 17,999
Fee income									1,300	1,349	1,488
Net investment income									2,305	2,177	2,313
Net realized gains (losses)									(188)	(627)	509
Other revenues									84	73	81
Total revenues	$ 6,400	$ 6,168	$ 6,049	$ 5,910	$ 6,016	$ 5,580	$ 5,373	$ 5,393	24,527	22,362	22,390
Benefits, losses and expenses
Benefits, losses and loss adjustment expenses									14,238	13,138	12,720
Amortization of deferred policy acquisition costs ("DAC")									2,044	1,824	1,668
Insurance operating costs and other expenses									4,881	4,841	4,791
Interest expense									199	213	234
Amortization of other intangible assets									71	71	71
Restructuring and other costs									6	13	1
Total benefits, losses and expenses	5,450	5,355	5,377	5,257	5,281	5,148	4,819	4,852	21,439	20,100	19,485
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest									3,088	2,262	2,905
Income tax expense									584	443	534
Net income	771	651	547	535	592	340	444	443	2,504	1,819	2,371
Less: Preferred stock dividends	5	6	5	5	5	6	5	5	21	21	21
Net income (loss) available to common stockholders	$ 766	$ 645	$ 542	$ 530	$ 587	$ 334	$ 439	$ 438	$ 2,483	$ 1,798	$ 2,350
Earnings per common share
Net income (loss) Basic	$ 2.55	$ 2.12	$ 1.75	$ 1.69	$ 1.85	$ 1.04	$ 1.34	$ 1.32	$ 8.09	$ 5.54	$ 6.73
Net income (loss) Diluted	$ 2.51	$ 2.09	$ 1.73	$ 1.66	$ 1.82	$ 1.02	$ 1.32	$ 1.30	$ 7.97	$ 5.46	$ 6.64