Investments (Details 2) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Amortized cost
Due in one year or less	$ 1,330
Due after one year through five years	8,486
Due after five years through ten years	7,889
Due after ten years	4,543
Subtotal	22,248
ABS, RMBS and CMBS	864
Amortized cost	23,112	$ 23,770
Fair value
Due in one year or less	1,345
Due after one year through five years	8,855
Due after five years through ten years	8,062
Due after ten years	5,055
Subtotal	23,317
ABS, RMBS and CMBS	905
Total	$ 24,222	$ 24,629