Reinsurance Reinsurance (Ceded Reinsurance Receivable Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Ceded Credit Risk [Line Items]
Reinsurance ceded receivables and other	$ 2,462	$ 2,580
Reinsurance Recoverables, Percentage of Total	100.00%	100.00%
Other Reinsurers [Member] | Customer Concentration Risk | Reinsurance Ceded Receivables Benchmark
Ceded Credit Risk [Line Items]
Reinsurance ceded receivables and other	$ 128	$ 174
Reinsurance Recoverables, Percentage of Total	5.20%	6.80%
AM Best, A+ Rating [Member] | Reinsurer A [Member] | Customer Concentration Risk | Reinsurance Ceded Receivables Benchmark
Ceded Credit Risk [Line Items]
Reinsurance ceded receivables and other	$ 1,605	$ 1,626
Reinsurance Recoverables, Percentage of Total	65.20%	63.00%
AM Best, A+ Rating [Member] | Reinsurer B [Member] | Customer Concentration Risk | Reinsurance Ceded Receivables Benchmark
Ceded Credit Risk [Line Items]
Reinsurance ceded receivables and other	$ 401	$ 423
Reinsurance Recoverables, Percentage of Total	16.30%	16.40%
AM Best, A+ Rating [Member] | Reinsurer C [Member] | Customer Concentration Risk | Reinsurance Ceded Receivables Benchmark
Ceded Credit Risk [Line Items]
Reinsurance ceded receivables and other	$ 200	$ 212
Reinsurance Recoverables, Percentage of Total	8.10%	8.20%
AM Best, A+ Rating [Member] | Reinsurer E [Member] | Customer Concentration Risk | Reinsurance Ceded Receivables Benchmark
Ceded Credit Risk [Line Items]
Reinsurance ceded receivables and other	$ 41	$ 44
Reinsurance Recoverables, Percentage of Total	1.70%	1.70%
AM Best, A Rating [Member] | Reinsurer D [Member] | Customer Concentration Risk | Reinsurance Ceded Receivables Benchmark
Ceded Credit Risk [Line Items]
Reinsurance ceded receivables and other	$ 52	$ 59
Reinsurance Recoverables, Percentage of Total	2.10%	2.30%
AM Best, A++ Rating [Member] | Reinsurer F | Customer Concentration Risk | Reinsurance Ceded Receivables Benchmark
Ceded Credit Risk [Line Items]
Reinsurance ceded receivables and other	$ 35	$ 42
Reinsurance Recoverables, Percentage of Total	1.40%	1.60%