Schedule I - Summary of Investments Other than Investments in Related Parties (Details) $ in Millions	Dec. 31, 2019 USD ($)
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost	$ 84,017
Amount shown in the Balance Sheet	88,362
United States government, government agencies and authorities
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost	4,971
Fair value (if applicable)	5,086
Amount shown in the Balance Sheet	5,086
States, municipalities and political subdivisions
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost	8,080
Fair value (if applicable)	8,620
Amount shown in the Balance Sheet	8,620
Foreign governments
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost	968
Fair value (if applicable)	979
Amount shown in the Balance Sheet	979
Public utilities
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost	5,197
Fair value (if applicable)	5,576
Amount shown in the Balance Sheet	5,576
All other corporate bonds
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost	35,893
Fair value (if applicable)	37,502
Amount shown in the Balance Sheet	37,502
Asset-backed securities
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost	860
Fair value (if applicable)	862
Amount shown in the Balance Sheet	862
Mortgage-backed securities
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost	324
Fair value (if applicable)	419
Amount shown in the Balance Sheet	419
Total fixed maturities
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost	56,293
Fair value (if applicable)	59,044
Amount shown in the Balance Sheet	59,044
Public utilities
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost	98
Fair value (if applicable)	136
Amount shown in the Balance Sheet	136
Banks, trusts and insurance companies
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost	565
Fair value (if applicable)	771
Amount shown in the Balance Sheet	771
Industrial, miscellaneous and all other
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost	5,662
Fair value (if applicable)	6,957
Amount shown in the Balance Sheet	6,957
Nonredeemable preferred stocks
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost	243
Fair value (if applicable)	298
Amount shown in the Balance Sheet	298
Total equity securities
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost	6,568
Fair value (if applicable)	8,162
Amount shown in the Balance Sheet	8,162
Mortgage loans on real estate
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost	4,817
Fair value (if applicable)	5,012
Amount shown in the Balance Sheet	4,817
Real estate
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost	1,005
Amount shown in the Balance Sheet	1,005
Policy loans
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost	894
Amount shown in the Balance Sheet	894
Derivative instruments
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost	140
Fair value (if applicable)	140
Amount shown in the Balance Sheet	140
Limited partnership interests
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost	8,078
Amount shown in the Balance Sheet	8,078
Other long-term investments
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost	1,966
Amount shown in the Balance Sheet	1,966
Short-term investments
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost	4,256
Fair value (if applicable)	4,256
Amount shown in the Balance Sheet	$ 4,256