Schedule I - Summary Of Investments (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Cost	$ 2,734
Investments	2,955
Available-for-sale Securities, Amortized Cost Basis	2,140	$ 2,807
Other Investments	690	595
Available-for-sale Securities	2,265
Investments	2,955	3,544
Short-term Investments [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	415	492
Available-for-sale Securities	414	492
ShortTermInvestmentsMember, including Pledged
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	520
Available-for-sale Securities	519
Other Investments [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	594
Available-for-sale Securities	683
Other Investments [Member] | Fixed Income Funds
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities	690
Fixed Income Securities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	1,605	2,175
Available-for-sale Securities	1,730	2,317
Fixed Income Securities [Member] | Municipal Bonds [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	315	321
Available-for-sale Securities	340	358
Fixed Income Securities [Member] | Corporate Debt Securities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	612	1,059
Available-for-sale Securities	613	1,077
Fixed Income Securities [Member] | Debt Security, Government, Non-US [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	89	97
Available-for-sale Securities	87	98
Fixed Income Securities [Member] | Residential Mortgage-Backed Securities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	182	256
Available-for-sale Securities	252	302
Fixed Income Securities [Member] | Collateralized Debt Obligations [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	128	74
Available-for-sale Securities	128	74
Fixed Income Securities [Member] | Asset-backed Securities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	234	263
Available-for-sale Securities	265	303
Fixed Income Securities [Member] | U S Government Obligations [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	60
Available-for-sale Securities	60
Fixed Income Securities [Member] | US Government Debt Securities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	45	105
Available-for-sale Securities	45	$ 106
Fixed Income Securities [Member] | Corporate Obligations, Excluding Related Party Investments
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	612
Available-for-sale Securities	613
Fair Value Amount, Excluding Related Party Investments [Domain]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Investments	$ 2,947