Fair Value Measurements - Significant Unobservable Inputs (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Actuarial Assumptions, Lapses, threshold percentage	93.00%	90.00%
Actuarial Assumptions, Policyholder Deposits, threshold percentage	7.00%	10.00%
FIA | Derivative Financial Instruments, Liabilities | Market Approach Valuation Technique | Minimum
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Interest Rate Implied Volatility	0.00%	0.00%
Fair Value Inputs, Actuarial Assumptions, Policyholder Deposits	0.00%	0.00%
FIA | Derivative Financial Instruments, Liabilities | Market Approach Valuation Technique | Maximum
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Interest Rate Implied Volatility	0.00%	0.00%
Fair Value Inputs, Actuarial Assumptions, Policyholder Deposits	0.00%	0.00%
FIA | Investment Contracts [Member] | Market Approach Valuation Technique | Minimum
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Actuarial Assumptions, Lapses	0.00%	0.00%
Fair Value Inputs, Nonperformance Risk	0.26%	0.23%
Fair Value Input, Actual Assumption, Partial Withdrawal	0.40%	0.40%
FIA | Investment Contracts [Member] | Market Approach Valuation Technique | Maximum
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Actuarial Assumptions, Lapses	45.00%	45.00%
Fair Value Inputs, Nonperformance Risk	1.90%	1.30%
Fair Value Input, Actual Assumption, Partial Withdrawal	3.20%	3.20%
Stabilizer Products and Managed Custody Guarantee (MCG) Products [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Percentage of Plans	100.00%	100.00%
Stabilizer Products and Managed Custody Guarantee (MCG) Products [Member] | Derivative Financial Instruments, Liabilities | Market Approach Valuation Technique | Minimum
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Actuarial Assumptions, Lapses	0.00%	0.00%
Fair Value Inputs, Nonperformance Risk	0.26%	0.23%
Fair Value Input, Actual Assumption, Partial Withdrawal	0.00%	0.00%
Fair Value Inputs, Interest Rate Implied Volatility	0.20%	0.10%
Actuarial Assumptions, Lapses under percent threshold	0.00%	0.00%
Actuarial Assumptions, Policyholder Deposits under percent threshold	0.00%	0.00%
Fair Value Inputs, Actuarial Assumptions, Policyholder Deposits	0.00%	0.00%
Stabilizer Products and Managed Custody Guarantee (MCG) Products [Member] | Derivative Financial Instruments, Liabilities | Market Approach Valuation Technique | Maximum
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Actuarial Assumptions, Lapses	50.00%	50.00%
Fair Value Inputs, Nonperformance Risk	1.90%	1.30%
Fair Value Input, Actual Assumption, Partial Withdrawal	0.00%	0.00%
Fair Value Inputs, Interest Rate Implied Volatility	7.60%	7.30%
Actuarial Assumptions, Lapses under percent threshold	30.00%	30.00%
Actuarial Assumptions, Policyholder Deposits under percent threshold	25.00%	25.00%
Fair Value Inputs, Actuarial Assumptions, Policyholder Deposits	50.00%	50.00%
Stabilizer (Investment Only) and MCG Contracts
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Percentage of Plans	93.00%	90.00%
Stabilizer (Investment Only) and MCG Contracts | Derivative Financial Instruments, Liabilities | Market Approach Valuation Technique | Minimum
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Actuarial Assumptions, Lapses	0.00%	0.00%
Actuarial Assumptions, Lapses under percent threshold	0.00%	0.00%
Actuarial Assumptions, Policyholder Deposits under percent threshold	0.00%	0.00%
Fair Value Inputs, Actuarial Assumptions, Policyholder Deposits	0.00%	0.00%
Stabilizer (Investment Only) and MCG Contracts | Derivative Financial Instruments, Liabilities | Market Approach Valuation Technique | Maximum
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Actuarial Assumptions, Lapses	25.00%	25.00%
Actuarial Assumptions, Lapses under percent threshold	15.00%	15.00%
Actuarial Assumptions, Policyholder Deposits under percent threshold	15.00%	15.00%
Fair Value Inputs, Actuarial Assumptions, Policyholder Deposits	30.00%	30.00%
Stabilizer with Recordkeeping Agreements
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Percentage of Plans	7.00%	10.00%
Stabilizer with Recordkeeping Agreements | Derivative Financial Instruments, Liabilities | Market Approach Valuation Technique | Minimum
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Actuarial Assumptions, Lapses	0.00%	0.00%
Actuarial Assumptions, Lapses under percent threshold	0.00%	0.00%
Actuarial Assumptions, Policyholder Deposits under percent threshold	0.00%	0.00%
Fair Value Inputs, Actuarial Assumptions, Policyholder Deposits	0.00%	0.00%
Stabilizer with Recordkeeping Agreements | Derivative Financial Instruments, Liabilities | Market Approach Valuation Technique | Maximum
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Actuarial Assumptions, Lapses	50.00%	50.00%
Actuarial Assumptions, Lapses under percent threshold	30.00%	30.00%
Actuarial Assumptions, Policyholder Deposits under percent threshold	25.00%	25.00%
Fair Value Inputs, Actuarial Assumptions, Policyholder Deposits	50.00%	50.00%