SCHEDULE I - SUMMARY OF INVESTMENTS OTHER THAN INVESTMENTS IN RELATED PARTIES (Details) $ in Millions	Dec. 31, 2015 USD ($)
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	$ 34,081
Amount at which shown in the Balance Sheet	34,962
United States government, government agencies and authorities
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	920
Fair value	977
Amount at which shown in the Balance Sheet	977
States, municipalities and political subdivisions
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	2,162
Fair value	2,442
Amount at which shown in the Balance Sheet	2,442
Foreign government
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	348
Fair value	384
Amount at which shown in the Balance Sheet	384
Public utilities
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	3,148
Fair value	3,411
Amount at which shown in the Balance Sheet	3,411
All other corporate bonds
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	14,921
Fair value	15,093
Amount at which shown in the Balance Sheet	15,093
Asset-backed securities
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	1,443
Fair value	1,420
Amount at which shown in the Balance Sheet	1,420
Residential mortgage-backed securities
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	406
Fair value	451
Amount at which shown in the Balance Sheet	451
CMBS
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	409
Fair value	436
Amount at which shown in the Balance Sheet	436
Redeemable preferred stock
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	13
Fair value	15
Amount at which shown in the Balance Sheet	15
Fixed income securities
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	23,770
Fair value	24,629
Amount at which shown in the Balance Sheet	24,629
Public utilities
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	39
Fair value	38
Amount at which shown in the Balance Sheet	38
Banks, trusts and insurance companies
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	379
Fair value	381
Amount at which shown in the Balance Sheet	381
Industrial, miscellaneous and all other
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	1,085
Fair value	1,103
Amount at which shown in the Balance Sheet	1,103
Nonredeemable preferred stocks
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	23
Fair value	20
Amount at which shown in the Balance Sheet	20
Equity securities
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	1,526
Fair value	1,542
Amount at which shown in the Balance Sheet	1,542
Mortgage loans on real estate
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	3,781
Fair value	3,920
Amount at which shown in the Balance Sheet	3,781
Real estate investment
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	72
Amount at which shown in the Balance Sheet	72
Real estate acquired in satisfaction of debt
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	6
Amount at which shown in the Balance Sheet	6
Policy loans
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	572
Amount at which shown in the Balance Sheet	572
Derivative instruments
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	43
Fair value	49
Amount at which shown in the Balance Sheet	49
Limited partnership interests
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	2,295
Amount at which shown in the Balance Sheet	2,295
Other long-term investments
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	1,206
Amount at which shown in the Balance Sheet	1,206
Short-term investments
Summary of Investments Other Than Investments in Related Parties
Cost/ amortized cost	816
Fair value	816
Amount at which shown in the Balance Sheet	$ 816