Fair Value of Assets and Liabilities (Details 2) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Quantitative information about the significant unobservable inputs
Fair Value	$ 24,629	$ 28,117
Significant unobservable inputs (Level 3)
Quantitative information about the significant unobservable inputs
Assets, Fair Value Disclosure	736	1,077
Fair value	(307)	$ (332)
Significant unobservable inputs (Level 3) | Derivatives embedded in life and annuity contracts – Equity-indexed and forward starting options | Stochastic cash flow model
Quantitative information about the significant unobservable inputs
Fair value	$ (247)
Weighted average projected option cost (as a percent)	1.76%
Significant unobservable inputs (Level 3) | Derivatives embedded in life and annuity contracts – Equity-indexed and forward starting options | Maximum | Stochastic cash flow model
Quantitative information about the significant unobservable inputs
Projected option cost (as a percent)	2.20%	2.00%
Significant unobservable inputs (Level 3) | Derivatives embedded in life and annuity contracts – Equity-indexed and forward starting options | Minimum | Stochastic cash flow model
Quantitative information about the significant unobservable inputs
Projected option cost (as a percent)	1.00%	1.00%
Significant unobservable inputs (Level 3) | Derivatives embedded in life and annuity contracts – Equity-indexed and forward starting options | Discounted cash flow model
Quantitative information about the significant unobservable inputs
Fair value		$ (278)
Weighted average projected option cost (as a percent)		1.76%
Significant unobservable inputs (Level 3) | Fixed income securities - non-binding broker quotes
Quantitative information about the significant unobservable inputs
Assets, Fair Value Disclosure	$ 577	$ 914
Recurring basis | Significant unobservable inputs (Level 3)
Quantitative information about the significant unobservable inputs
Fair Value	666	1,028
Assets, Fair Value Disclosure	$ 728	$ 1,068