Investments (Details 3) - Fixed Maturity [Member] $ in Millions	Mar. 31, 2016 USD ($)
Amortized Cost Basis, Fiscal Year Maturity [Abstract]
One year or less	$ 999
After one year through five years	5,348
After five years through ten years	11,678
After ten years	3,998
Fixed maturities amortized cost, Subtotal	22,023
ABS (average life of approximately 5 years)	5,172
MBS (average life of approximately 4-1/2 years)	5,554
Amortized Cost	32,749
Fair Value, Fiscal Year Maturity [Abstract]
One year or less	1,014
After one year through five years	5,612
After five years through ten years	12,025
After ten years	4,232
Fixed maturities fair value, Subtotal	22,883
ABS (average life of approximately 5 years)	5,130
MBS (average life of approximately 4-1/2 years)	5,908
Fair Value	$ 33,921
Fair Value Percent, Fiscal Year Maturity [Abstract]
One year or less	3.00%
After one year through five years	17.00%
After five years through ten years	35.00%
After ten years	13.00%
Fixed maturities fair value, Subtotal, Percent	68.00%
ABS (average life of approximately 5 years)	15.00%
MBS (average life of approximately 4-1/2 years)	17.00%
Fair value, Total, Percent	100.00%