Investments (Details 3) - Fixed Maturity [Member] $ in Millions	Sep. 30, 2015 USD ($)
Amortized Cost Basis, Fiscal Year Maturity [Abstract]
One year or less	$ 1,016
After one year through five years	5,300
After five years through ten years	10,439
After ten years	4,715
Fixed maturities amortized cost, Subtotal	21,470
ABS (average life of approximately 5 years)	4,673
MBS (average life of approximately 4-1/2 years)	5,725
Amortized Cost	31,868
Fair Value, Fiscal Year Maturity [Abstract]
One year or less	1,032
After one year through five years	5,604
After five years through ten years	10,679
After ten years	4,922
Fixed maturities fair value, Subtotal	22,237
ABS (average life of approximately 5 years)	4,701
MBS (average life of approximately 4-1/2 years)	6,176
Fair Value	$ 33,114
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	32.00%
After ten years	15.00%
Fixed maturities fair value, Subtotal, Percent	67.00%
ABS (average life of approximately 5 years)	14.00%
MBS (average life of approximately 4-1/2 years)	19.00%
Fair value, Total, Percent	100.00%