Investments (Details 2) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Amortized cost
Amortized cost, fixed maturities	$ 9,687
Estimated fair value
Estimated fair value, fixed maturities	9,980	$ 9,571
Indemnity
Amortized cost
Due in one year or less	68
Due after one year through five years	261
Due after five years through ten years	161
Due after ten years	91
Amortized cost, fixed maturities	581	555
Estimated fair value
Due in one year or less	68
Due after one year through five years	261
Due after five years through ten years	165
Due after ten years	94
Estimated fair value, fixed maturities	588	564
Exchange
Amortized cost
Due in one year or less	432
Due after one year through five years	3,364
Due after five years through ten years	3,849
Due after ten years	1,461
Amortized cost, fixed maturities	9,106	8,540
Estimated fair value
Due in one year or less	438
Due after one year through five years	3,524
Due after five years through ten years	3,909
Due after ten years	1,521
Estimated fair value, fixed maturities	$ 9,392	$ 9,007