Investments - Scheduled maturities of available for sale fixed maturities (Details) $ in Millions	6 Months Ended
	Jun. 30, 2019 USD ($)
Fair Value Percent, Fiscal Year Maturity [Abstract]
Average life of ABS	4 years 6 months
Average life of MBS	4 years 6 months
Fixed maturities
Amortized Cost Basis, Fiscal Year Maturity [Abstract]
One year or less	$ 1,580
After one year through five years	10,179
After five years through ten years	14,140
After ten years	3,595
Fixed maturities amortized cost, Subtotal	29,494
Collateralized loan obligations and other ABS (average life of approximately 4.5 years)	10,108
MBS (average life of approximately 4.5 years)	3,306
Amortized Cost	42,908
Fair Value, Fiscal Year Maturity [Abstract]
One year or less	1,601
After one year through five years	10,523
After five years through ten years	14,861
After ten years	3,807
Fixed maturities fair value, Subtotal	30,792
Collateralized loan obligations and other ABS (average life of approximately 4.5 years)	10,277
MBS (average life of approximately 4.5 years)	3,641
Fair Value	$ 44,710
Fair Value Percent, Fiscal Year Maturity [Abstract]
One year or less	4.00%
After one year through five years	24.00%
After five years through ten years	33.00%
After ten years	8.00%
Fixed maturities fair value, Subtotal, Percent	69.00%
Collateralized loan obligations and other ABS (average life of approximately 4.5 years)	23.00%
MBS (average life of approximately 4.5 years)	8.00%
Fair value, Total, Percent	100.00%