Investments (Details 2) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Amortized cost
Due in one year or less	$ 4,873
Due after one year through five years	27,836
Due after five years through ten years	16,448
Due after ten years	5,337
Subtotal	54,494
ABS, RMBS and CMBS	2,082
Amortized cost	56,576	$ 57,201
Fair value
Due in one year or less	4,898
Due after one year through five years	28,307
Due after five years through ten years	16,612
Due after ten years	5,853
Subtotal	55,670
ABS, RMBS and CMBS	2,169
Fair value	$ 57,839	$ 57,948