Investments - Scheduled maturities of available for sale fixed maturities (Details) $ in Millions	6 Months Ended
	Jun. 30, 2020 USD ($)
Fair Value Percent, Fiscal Year Maturity [Abstract]
Average life of ABS	4 years
Average life of MBS	3 years 6 months
Fixed maturities
Amortized Cost Basis, Fiscal Year Maturity [Abstract]
One year or less	$ 1,851	[1]
After one year through five years	10,604	[1]
After five years through ten years	14,125	[1]
After ten years	3,191	[1]
Fixed maturities amortized cost, Subtotal	29,771	[1]
Collateralized loan obligations and other ABS (average life of approximately 4 years)	11,991	[1]
MBS (average life of approximately 3-1/2 years)	3,847	[1]
Amortized Cost	45,609	[1]
Fair Value, Fiscal Year Maturity [Abstract]
One year or less	1,874
After one year through five years	11,212
After five years through ten years	15,485
After ten years	3,542
Fixed maturities fair value, Subtotal	32,113
Collateralized loan obligations and other ABS (average life of approximately 4 years)	11,822
MBS (average life of approximately 3-1/2 years)	4,111
Fair Value	$ 48,046
Fair Value Percent, Fiscal Year Maturity [Abstract]
One year or less	4.00%
After one year through five years	23.00%
After five years through ten years	32.00%
After ten years	7.00%
Fixed maturities fair value, Subtotal, Percent	66.00%
Collateralized loan obligations and other ABS (average life of approximately 4 years)	25.00%
MBS (average life of approximately 3-1/2 years)	9.00%
Fair value, Total, Percent	100.00%

[1] Amortized cost, net of allowance for expected credit losses.