Fair Value (Recurring Fair Value Measurements) (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022	Dec. 31, 2021
Assets [Abstract]
Fixed maturity securities, estimated fair value	$ 74,571	$ 74,757
Equity securities	61	66
Short-term investments	489	299
Derivative assets	2,500	2,271
Market risk benefit assets	694	483
Separate account assets	76,602	78,880
Liabilities [Abstract]
Market risk benefit liabilities	8,850	10,411	$ 16,062
Derivative liabilities	4,991	3,911
Recurring
Assets [Abstract]
Fixed maturity securities, estimated fair value	74,571	74,757
Equity securities	61	66
Short-term investments	489	299
Derivative assets	2,500	2,271
Market risk benefit assets	694	483
Separate account assets	76,602	78,880
Total assets	154,917	156,756
Liabilities [Abstract]
Market risk benefit liabilities	8,850	10,411
Derivative liabilities	4,991	3,911
Embedded derivatives on index-linked annuities (2)	6,031	3,932
Total liabilities	19,872	18,254
Recurring | Interest rate
Assets [Abstract]
Derivative assets	447	304
Liabilities [Abstract]
Derivative liabilities	3,478	2,802
Recurring | Foreign currency exchange rate
Assets [Abstract]
Derivative assets	586	732
Liabilities [Abstract]
Derivative liabilities	15	9
Recurring | Credit
Assets [Abstract]
Derivative assets	21	18
Liabilities [Abstract]
Derivative liabilities	1	2
Recurring | Equity market
Assets [Abstract]
Derivative assets	1,446	1,217
Liabilities [Abstract]
Derivative liabilities	1,497	1,098
Recurring | U.S. corporate
Assets [Abstract]
Fixed maturity securities, estimated fair value	32,493	32,162
Recurring | Foreign corporate
Assets [Abstract]
Fixed maturity securities, estimated fair value	10,599	10,492
Recurring | U.S. government and agency
Assets [Abstract]
Fixed maturity securities, estimated fair value	7,653	7,898
Recurring | RMBS
Assets [Abstract]
Fixed maturity securities, estimated fair value	6,966	7,491
Recurring | CMBS
Assets [Abstract]
Fixed maturity securities, estimated fair value	6,237	6,537
Recurring | ABS
Assets [Abstract]
Fixed maturity securities, estimated fair value	6,110	5,355
Recurring | State and political subdivision
Assets [Abstract]
Fixed maturity securities, estimated fair value	3,547	3,741
Recurring | Foreign government
Assets [Abstract]
Fixed maturity securities, estimated fair value	966	1,081
Recurring | Level 1
Assets [Abstract]
Fixed maturity securities, estimated fair value	3,605	3,507
Equity securities	10	12
Short-term investments	367	206
Derivative assets	0	0
Market risk benefit assets	0	0
Separate account assets	16	29
Total assets	3,998	3,754
Liabilities [Abstract]
Market risk benefit liabilities	0	0
Derivative liabilities	0	0
Embedded derivatives on index-linked annuities (2)	0	0
Total liabilities	0	0
Recurring | Level 1 | Interest rate
Assets [Abstract]
Derivative assets	0	0
Liabilities [Abstract]
Derivative liabilities	0	0
Recurring | Level 1 | Foreign currency exchange rate
Assets [Abstract]
Derivative assets	0	0
Liabilities [Abstract]
Derivative liabilities	0	0
Recurring | Level 1 | Credit
Assets [Abstract]
Derivative assets	0	0
Liabilities [Abstract]
Derivative liabilities	0	0
Recurring | Level 1 | Equity market
Assets [Abstract]
Derivative assets	0	0
Liabilities [Abstract]
Derivative liabilities	0	0
Recurring | Level 1 | U.S. corporate
Assets [Abstract]
Fixed maturity securities, estimated fair value	0	0
Recurring | Level 1 | Foreign corporate
Assets [Abstract]
Fixed maturity securities, estimated fair value	0	0
Recurring | Level 1 | U.S. government and agency
Assets [Abstract]
Fixed maturity securities, estimated fair value	3,605	3,507
Recurring | Level 1 | RMBS
Assets [Abstract]
Fixed maturity securities, estimated fair value	0	0
Recurring | Level 1 | CMBS
Assets [Abstract]
Fixed maturity securities, estimated fair value	0	0
Recurring | Level 1 | ABS
Assets [Abstract]
Fixed maturity securities, estimated fair value	0	0
Recurring | Level 1 | State and political subdivision
Assets [Abstract]
Fixed maturity securities, estimated fair value	0	0
Recurring | Level 1 | Foreign government
Assets [Abstract]
Fixed maturity securities, estimated fair value	0	0
Recurring | Level 2
Assets [Abstract]
Fixed maturity securities, estimated fair value	69,448	69,060
Equity securities	26	27
Short-term investments	122	93
Derivative assets	2,473	2,234
Market risk benefit assets	0	0
Separate account assets	76,586	78,851
Total assets	148,655	150,265
Liabilities [Abstract]
Market risk benefit liabilities	0	0
Derivative liabilities	4,990	3,909
Embedded derivatives on index-linked annuities (2)	0	0
Total liabilities	4,990	3,909
Recurring | Level 2 | Interest rate
Assets [Abstract]
Derivative assets	447	304
Liabilities [Abstract]
Derivative liabilities	3,478	2,802
Recurring | Level 2 | Foreign currency exchange rate
Assets [Abstract]
Derivative assets	573	703
Liabilities [Abstract]
Derivative liabilities	15	9
Recurring | Level 2 | Credit
Assets [Abstract]
Derivative assets	14	10
Liabilities [Abstract]
Derivative liabilities	0	0
Recurring | Level 2 | Equity market
Assets [Abstract]
Derivative assets	1,439	1,217
Liabilities [Abstract]
Derivative liabilities	1,497	1,098
Recurring | Level 2 | U.S. corporate
Assets [Abstract]
Fixed maturity securities, estimated fair value	31,669	30,973
Recurring | Level 2 | Foreign corporate
Assets [Abstract]
Fixed maturity securities, estimated fair value	10,283	9,894
Recurring | Level 2 | U.S. government and agency
Assets [Abstract]
Fixed maturity securities, estimated fair value	4,048	4,391
Recurring | Level 2 | RMBS
Assets [Abstract]
Fixed maturity securities, estimated fair value	6,957	7,477
Recurring | Level 2 | CMBS
Assets [Abstract]
Fixed maturity securities, estimated fair value	6,201	6,504
Recurring | Level 2 | ABS
Assets [Abstract]
Fixed maturity securities, estimated fair value	5,810	5,037
Recurring | Level 2 | State and political subdivision
Assets [Abstract]
Fixed maturity securities, estimated fair value	3,547	3,741
Recurring | Level 2 | Foreign government
Assets [Abstract]
Fixed maturity securities, estimated fair value	933	1,043
Recurring | Level 3
Assets [Abstract]
Fixed maturity securities, estimated fair value	1,518	2,190
Equity securities	25	27
Short-term investments	0	0
Derivative assets	27	37
Market risk benefit assets	694	483
Separate account assets	0	0
Total assets	2,264	2,737
Liabilities [Abstract]
Market risk benefit liabilities	8,850	10,411
Derivative liabilities	1	2
Embedded derivatives on index-linked annuities (2)	6,031	3,932
Total liabilities	14,882	14,345
Recurring | Level 3 | Interest rate
Assets [Abstract]
Derivative assets	0	0
Liabilities [Abstract]
Derivative liabilities	0	0
Recurring | Level 3 | Foreign currency exchange rate
Assets [Abstract]
Derivative assets	13	29
Liabilities [Abstract]
Derivative liabilities	0	0
Recurring | Level 3 | Credit
Assets [Abstract]
Derivative assets	7	8
Liabilities [Abstract]
Derivative liabilities	1	2
Recurring | Level 3 | Equity market
Assets [Abstract]
Derivative assets	7	0
Liabilities [Abstract]
Derivative liabilities	0	0
Recurring | Level 3 | U.S. corporate
Assets [Abstract]
Fixed maturity securities, estimated fair value	824	1,189
Recurring | Level 3 | Foreign corporate
Assets [Abstract]
Fixed maturity securities, estimated fair value	316	598
Recurring | Level 3 | U.S. government and agency
Assets [Abstract]
Fixed maturity securities, estimated fair value	0	0
Recurring | Level 3 | RMBS
Assets [Abstract]
Fixed maturity securities, estimated fair value	9	14
Recurring | Level 3 | CMBS
Assets [Abstract]
Fixed maturity securities, estimated fair value	36	33
Recurring | Level 3 | ABS
Assets [Abstract]
Fixed maturity securities, estimated fair value	300	318
Recurring | Level 3 | State and political subdivision
Assets [Abstract]
Fixed maturity securities, estimated fair value	0	0
Recurring | Level 3 | Foreign government
Assets [Abstract]
Fixed maturity securities, estimated fair value	$ 33	$ 38