Schedule II-Condensed Financial Information Of Registrant (Balance Sheets - Additional Information) (Details) - USD ($) $ / shares in Units, $ in Millions	Sep. 30, 2023	Dec. 31, 2022	Dec. 31, 2021
Available For Sale Securities, Amortized Cost	$ 31,013	$ 29,015
Fixed Maturity Securities, Allowance for Credit Loss	$ 3	$ 9	$ 6
Preferred stock, shares authorized	100,000,000	100,000,000	100,000,000
Preferred stock, shares issued	0	0	0
Preferred stock, shares outstanding	0	0	0
Common stock, par value	$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized	900,000,000	900,000,000	900,000,000
Common stock, shares issued	234,906,987	237,958,067	241,770,746
Common stock, shares outstanding	234,906,987	237,958,067	241,770,746
Anthem, Inc. [Member]
Available For Sale Securities, Amortized Cost		$ 175	$ 512
Fixed Maturity Securities, Allowance for Credit Loss		$ 0	$ 1
Preferred stock, shares authorized		100,000,000
Preferred stock, shares issued		0
Preferred stock, shares outstanding		0
Common stock, par value		$ 0.01
Common stock, shares authorized		900,000,000
Common stock, shares issued		237,958,067	241,770,746
Common stock, shares outstanding		237,958,067	241,770,746