Schedule II-Condensed Financial Information of Registrant (Statement of Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Shareholders' net income	$ 1,289	$ 1,603	$ 5,131	$ 5,029	$ 5,894	$ 6,158	$ 4,572
Other comprehensive (loss) income, net of tax:
Change in net unrealized gains/losses on investments	(352)	(639)	(44)	(2,630)	(2,260)	(457)	428
Change in net unrealized gains/losses on cash flow hedges	1	2	16	8	10	11	12
Change in net periodic pension and postretirement costs	2	7	7	23	(70)	123	(1)
Change in future policy benefits	3	7	2	24	32	(7)	0
Foreign currency translation adjustments	(4)	(7)	(2)	(15)	(13)	(9)	7
Total shareholders’ comprehensive income	$ 943	$ 975	$ 5,109	$ 2,447	3,601	5,823	5,018
Anthem, Inc. [Member]
Shareholders' net income					5,894	6,158	4,572
Other comprehensive (loss) income, net of tax:
Change in net unrealized gains/losses on investments					(2,249)	(455)	428
Change in non-credit component of impairment losses on investments					(3)	2	0
Change in net unrealized gains/losses on cash flow hedges					10	11	12
Change in net periodic pension and postretirement costs					(70)	123	(1)
Change in future policy benefits					32	(7)	0
Foreign currency translation adjustments					(13)	(9)	7
Other comprehensive (loss) income					(2,293)	(335)	446
Total shareholders’ comprehensive income					$ 3,601	$ 5,823	$ 5,018