SCHEDULE I SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	$ 12,279
Estimated fair value	13,866
Amount at which shown in the balance sheet	13,866
Indemnity
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	692
Estimated fair value	723
Amount at which shown in the balance sheet	723
Indemnity | Available-for-sale securities
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	568
Estimated fair value	576
Amount at which shown in the balance sheet	576
Indemnity | States & political subdivisions | Available-for-sale securities
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	237
Estimated fair value	243
Amount at which shown in the balance sheet	243
Indemnity | Corporate debt securities | Available-for-sale securities
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	280
Estimated fair value	282
Amount at which shown in the balance sheet	282
Indemnity | Collateralized debt obligations | Available-for-sale securities
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	1
Estimated fair value	1
Amount at which shown in the balance sheet	1
Indemnity | Nonredeemable preferred stock | Available-for-sale securities
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	24
Estimated fair value	25
Amount at which shown in the balance sheet	25
Indemnity | Common stock | Available-for-sale securities
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	26
Estimated fair value	25
Amount at which shown in the balance sheet	25
Indemnity | Limited partnerships
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	123
Estimated fair value	146
Amount at which shown in the balance sheet	146
Indemnity | Real estate mortgage loans
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	1
Estimated fair value	1
Amount at which shown in the balance sheet	1
Exchange
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	11,587
Estimated fair value	13,143
Amount at which shown in the balance sheet	13,143
Exchange | Available-for-sale securities
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	8,579
Estimated fair value	8,981
Amount at which shown in the balance sheet	8,981
Exchange | Trading securities
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	2,198
Estimated fair value	3,202
Amount at which shown in the balance sheet	3,202
Exchange | U.S. government & agencies | Available-for-sale securities
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	171
Estimated fair value	172
Amount at which shown in the balance sheet	172
Exchange | States & political subdivisions | Available-for-sale securities
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	1,430
Estimated fair value	1,470
Amount at which shown in the balance sheet	1,470
Exchange | Foreign government securities | Available-for-sale securities
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	15
Estimated fair value	15
Amount at which shown in the balance sheet	15
Exchange | Corporate debt securities | Available-for-sale securities
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	5,902
Estimated fair value	6,211
Amount at which shown in the balance sheet	6,211
Exchange | Residential mortgage-backed securities | Available-for-sale securities
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	157
Estimated fair value	156
Amount at which shown in the balance sheet	156
Exchange | Commercial mortgage-backed securities | Available-for-sale securities
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	45
Estimated fair value	47
Amount at which shown in the balance sheet	47
Exchange | Collateralized debt obligations | Available-for-sale securities
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	8
Estimated fair value	16
Amount at which shown in the balance sheet	16
Exchange | Other debt securities | Available-for-sale securities
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	73
Estimated fair value	75
Amount at which shown in the balance sheet	75
Exchange | Nonredeemable preferred stock | Available-for-sale securities
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	577
Estimated fair value	621
Amount at which shown in the balance sheet	621
Exchange | Common stock | Available-for-sale securities
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	201
Estimated fair value	198
Amount at which shown in the balance sheet	198
Exchange | Limited partnerships
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	790
Estimated fair value	940
Amount at which shown in the balance sheet	940
Exchange | Life policy loans
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	17
Estimated fair value	17
Amount at which shown in the balance sheet	17
Exchange | Real estate mortgage loans
SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Amortized cost	3
Estimated fair value	3
Amount at which shown in the balance sheet	$ 3