Fair Value of Assets and Liabilities (Details 5) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Financial assets
Mortgage loans	$ 4,302	$ 4,338
Financial liabilities
Long-term debt	5,108	5,124
Liability for collateral	874	840	$ 755	$ 782
Carrying value
Financial assets
Mortgage loans	4,302	4,338
Cost method limited partnerships	1,193	1,154
Bank loans	1,613	1,565
Agent loans	437	422
Financial liabilities
Contractholder funds on investment contracts	12,190	12,424
Long-term debt	5,108	5,124
Liability for collateral	874	840
Fair value
Financial assets
Mortgage loans	4,506	4,489
Cost method limited partnerships	1,466	1,450
Bank loans	1,578	1,527
Agent loans	427	408
Financial liabilities
Contractholder funds on investment contracts	12,621	12,874
Long-term debt	5,746	5,648
Liability for collateral	$ 874	$ 840