Adoption of ASU 2018-12 (Summary of Changes in DFEL) (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2012
DFEL	$ 5,646	$ 5,045
Accounting Standards Update 2018-12 [Member]
DFEL				$ 3,586
UL and Other [Member]
DFEL	5,343	4,735	$ 3,902		$ 4,735
UL and Other [Member] | Accounting Standards Update 2018-12 [Member]
DFEL				3,262
As Previously Reported [Member] | Accounting Standards Update 2018-12 [Member]
DFEL		5,695		396
As Previously Reported [Member] | UL and Other [Member] | Accounting Standards Update 2018-12 [Member]
DFEL				77
Restatement Adjustments [Member] | Accounting Standards Update 2018-12 [Member]
DFEL				3,190
Restatement Adjustments [Member] | UL and Other [Member] | Accounting Standards Update 2018-12 [Member]
DFEL				3,185
Variable Annuities [Member]
DFEL	$ 303	$ 310	$ 318		$ 310
Variable Annuities [Member] | Accounting Standards Update 2018-12 [Member]
DFEL				324
Variable Annuities [Member] | As Previously Reported [Member] | Accounting Standards Update 2018-12 [Member]
DFEL				319
Variable Annuities [Member] | Restatement Adjustments [Member] | Accounting Standards Update 2018-12 [Member]
DFEL				$ 5