Investments - Scheduled maturities of available for sale fixed maturities (Details) $ in Millions	9 Months Ended
	Sep. 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	$ 2,223
After one year through five years	10,338
After five years through ten years	13,997
After ten years	3,715
Fixed maturities amortized cost, Subtotal	30,273
Collateralized loan obligations and other ABS (average life of approximately 4.5 years)	9,859
MBS (average life of approximately 4.5 years)	3,202
Amortized Cost	43,334
Fair Value, Fiscal Year Maturity [Abstract]
One year or less	2,249
After one year through five years	10,742
After five years through ten years	14,927
After ten years	4,012
Fixed maturities fair value, Subtotal	31,930
Collateralized loan obligations and other ABS (average life of approximately 4.5 years)	10,045
MBS (average life of approximately 4.5 years)	3,528
Fair Value	$ 45,503
Fair Value Percent, Fiscal Year Maturity [Abstract]
One year or less	5.00%
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	70.00%
Collateralized loan obligations and other ABS (average life of approximately 4.5 years)	22.00%
MBS (average life of approximately 4.5 years)	8.00%
Fair value, Total, Percent	100.00%