Investments - Scheduled maturities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Amortized cost
Due in one year or less	$ 1,360
Due after one year through five years	7,690
Due after five years through ten years	7,455
Due after ten years	3,269
Subtotal	19,774
ABS and MBS	443
Amortized cost	20,217	$ 21,057
Fair value
Due in one year or less	1,374
Due after one year through five years	7,994
Due after five years through ten years	7,955
Due after ten years	3,904
Subtotal	21,227
ABS and MBS	498
Total	$ 21,725	$ 21,400