Schedule I - Summary of Investments Other than Investments in Related Parties (Details) $ in Millions	Dec. 31, 2020 USD ($)
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost, net	$ 88,477
Amount shown in the Balance Sheet	94,237
United States government, government agencies and authorities
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost, net	3,129
Fair value (if applicable)	3,222
Amount shown in the Balance Sheet	3,222
States, municipalities and political subdivisions
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost, net	8,752
Fair value (if applicable)	9,587
Amount shown in the Balance Sheet	9,587
Foreign governments
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost, net	1,013
Fair value (if applicable)	1,055
Amount shown in the Balance Sheet	1,055
Public utilities
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost, net	5,948
Fair value (if applicable)	6,564
Amount shown in the Balance Sheet	6,564
All other corporate bonds
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost, net	41,278
Fair value (if applicable)	44,578
Amount shown in the Balance Sheet	44,578
Asset-backed securities
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost, net	1,260
Fair value (if applicable)	1,270
Amount shown in the Balance Sheet	1,270
Mortgage-backed securities
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost, net	71
Fair value (if applicable)	78
Amount shown in the Balance Sheet	78
Total fixed maturities
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost, net	61,451
Fair value (if applicable)	66,354
Amount shown in the Balance Sheet	66,354
Public utilities
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost, net	34
Fair value (if applicable)	46
Amount shown in the Balance Sheet	46
Banks, trusts and insurance companies
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost, net	174
Fair value (if applicable)	255
Amount shown in the Balance Sheet	255
Industrial, miscellaneous and all other
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost, net	3,393
Fair value (if applicable)	4,087
Amount shown in the Balance Sheet	4,087
Nonredeemable preferred stocks
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost, net	252
Fair value (if applicable)	322
Amount shown in the Balance Sheet	322
Total equity securities
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost, net	3,853
Fair value (if applicable)	4,710
Amount shown in the Balance Sheet	4,710
Mortgage loans on real estate
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost, net	4,075
Fair value (if applicable)	4,348
Amount shown in the Balance Sheet	4,075
Real estate (none acquired in satisfaction of debt)
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost, net	974
Amount shown in the Balance Sheet	974
Policy loans
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost, net	754
Amount shown in the Balance Sheet	754
Derivative instruments
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost, net	204
Fair value (if applicable)	204
Amount shown in the Balance Sheet	204
Limited partnership interests
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost, net	7,609
Amount shown in the Balance Sheet	7,609
Other long-term investments
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost, net	1,757
Amount shown in the Balance Sheet	1,757
Short-term investments
Summary of Investments Other Than Investments in Related Parties
Cost/amortized cost, net	7,800
Fair value (if applicable)	7,800
Amount shown in the Balance Sheet	$ 7,800