Investments - Scheduled maturities for fixed income securities (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Amortized cost
Due in one year or less	$ 3,309
Due after one year through five years	26,701
Due after five years through ten years	16,622
Due after ten years	8,718
Subtotal	55,350
ABS, RMBS and CMBS	1,481
Amortized cost	56,831	$ 57,134
Fair value
Due in one year or less	3,324
Due after one year through five years	26,996
Due after five years through ten years	16,946
Due after ten years	9,363
Subtotal	56,629
ABS, RMBS and CMBS	1,573
Total fixed income securities	$ 58,202	$ 57,170