SCHEDULE I - SUMMARY OF INVESTMENTS OTHER THAN INVESTMENTS IN RELATED PARTIES (Details) $ in Millions	Dec. 31, 2016 USD ($)
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	$ 33,870
Amount at which shown in the Balance Sheet	35,067
United States government, government agencies and authorities
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	968
Fair value	1,014
Amount at which shown in the Balance Sheet	1,014
States, municipalities and political subdivisions
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	2,017
Fair value	2,274
Amount at which shown in the Balance Sheet	2,274
Foreign government
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	304
Fair value	332
Amount at which shown in the Balance Sheet	332
Public utilities
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	3,339
Fair value	3,611
Amount at which shown in the Balance Sheet	3,611
All other corporate bonds
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	15,606
Fair value	16,070
Amount at which shown in the Balance Sheet	16,070
Asset-backed securities
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	337
Fair value	331
Amount at which shown in the Balance Sheet	331
Residential mortgage-backed securities
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	294
Fair value	333
Amount at which shown in the Balance Sheet	333
CMBS
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	233
Fair value	241
Amount at which shown in the Balance Sheet	241
Redeemable preferred stock
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	14
Fair value	16
Amount at which shown in the Balance Sheet	16
Fixed income securities
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	23,112
Fair value	24,222
Amount at which shown in the Balance Sheet	24,222
Public utilities
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	31
Fair value	32
Amount at which shown in the Balance Sheet	32
Banks, trusts and insurance companies
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	203
Fair value	218
Amount at which shown in the Balance Sheet	218
Industrial, miscellaneous and all other
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	1,181
Fair value	1,246
Amount at which shown in the Balance Sheet	1,246
Nonredeemable preferred stocks
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	14
Fair value	15
Amount at which shown in the Balance Sheet	15
Equity securities
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	1,429
Fair value	1,511
Amount at which shown in the Balance Sheet	1,511
Mortgage loans on real estate
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	3,938
Fair value	3,963
Amount at which shown in the Balance Sheet	3,938
Real estate investment
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	129
Amount at which shown in the Balance Sheet	129
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
Policy loans
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	563
Amount at which shown in the Balance Sheet	563
Derivative instruments
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	91
Fair value	96
Amount at which shown in the Balance Sheet	96
Limited partnership interests
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	2,776
Amount at which shown in the Balance Sheet	2,776
Other long-term investments
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	1,266
Amount at which shown in the Balance Sheet	1,266
Short-term investments
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	566
Fair value	566
Amount at which shown in the Balance Sheet	$ 566