SCHEDULE I - SUMMARY OF INVESTMENTS OTHER THAN INVESTMENTS IN RELATED PARTIES (Details) $ in Millions	Dec. 31, 2018 USD ($)
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	$ 32,212
Amount at which shown in the Balance Sheet	32,683
United States government, government agencies and authorities
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	740
Fair value	773
Amount at which shown in the Balance Sheet	773
States, municipalities and political subdivisions
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	1,997
Fair value	2,195
Amount at which shown in the Balance Sheet	2,195
Foreign government
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	170
Fair value	179
Amount at which shown in the Balance Sheet	179
Public utilities
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	3,302
Fair value	3,443
Amount at which shown in the Balance Sheet	3,443
All other corporate bonds
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	14,219
Fair value	14,130
Amount at which shown in the Balance Sheet	14,130
Asset-backed securities
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	429
Fair value	429
Amount at which shown in the Balance Sheet	429
Residential mortgage-backed securities
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	154
Fair value	197
Amount at which shown in the Balance Sheet	197
CMBS
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	33
Fair value	40
Amount at which shown in the Balance Sheet	40
Redeemable preferred stock
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	13
Fair value	14
Amount at which shown in the Balance Sheet	14
Fixed income securities
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	21,057
Fair value	21,400
Amount at which shown in the Balance Sheet	21,400
Public utilities
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	21
Fair value	26
Amount at which shown in the Balance Sheet	26
Banks, trusts and insurance companies
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	101
Fair value	120
Amount at which shown in the Balance Sheet	120
Industrial, miscellaneous and all other
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	1,048
Fair value	1,153
Amount at which shown in the Balance Sheet	1,153
Nonredeemable preferred stocks
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	27
Fair value	26
Amount at which shown in the Balance Sheet	26
Equity securities
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	1,197
Fair value	1,325
Amount at which shown in the Balance Sheet	1,325
Mortgage loans on real estate
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	3,995
Fair value	4,028
Amount at which shown in the Balance Sheet	3,995
Real Estate Acquired in Satisfaction of Debt
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	0
Amount at which shown in the Balance Sheet	0
Real estate investment
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	228
Amount at which shown in the Balance Sheet	228
Policy loans
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	561
Amount at which shown in the Balance Sheet	561
Derivative instruments
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	23
Fair value	23
Amount at which shown in the Balance Sheet	23
Limited partnership interests
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	3,292
Amount at which shown in the Balance Sheet	3,292
Other long-term investments
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	1,049
Amount at which shown in the Balance Sheet	1,049
Short-term investments
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	810
Fair value	810
Amount at which shown in the Balance Sheet	$ 810