Fair Value Measurements Level 4 Significant Unobservable Inputs (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Alternative Investments, Fair Value Disclosure	2,942	3,040
Available-for-sale Securities, Debt Securities	59,384	62,357
Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities, Debt Securities	3,475	4,154
Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Measurements, Valuation Techniques	Discounted cash flows	Discounted cash flows
Residential Mortgage Backed Securities [Member] | Minimum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Loss Severity	0.00%	0.00%
Fair Value Inputs, Probability of Default	1.00%	1.00%
Fair Value Inputs, Prepayment Rate	0.00%	0.00%
Fair Value Inputs, Counterparty Credit Risk	23.00%	62.00%
Residential Mortgage Backed Securities [Member] | Maximum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Loss Severity	100.00%	100.00%
Fair Value Inputs, Probability of Default	14.00%	22.00%
Fair Value Inputs, Prepayment Rate	7.00%	10.00%
Fair Value Inputs, Counterparty Credit Risk	1904.00%	1748.00%
Residential Mortgage Backed Securities [Member] | Weighted Average [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Loss Severity	78.00%	80.00%
Fair Value Inputs, Probability of Default	7.00%	8.00%
Fair Value Inputs, Prepayment Rate	2.00%	3.00%
Fair Value Inputs, Counterparty Credit Risk	142.00%	232.00%
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Measurements, Valuation Techniques	Discounted cash flows	Discounted cash flows
Fair Value Measurements, Significant Assumptions	Spread	Spread
Fair Value Measurements, Sensitivity Analysis, Description	Decrease	Decrease
US States and Political Subdivisions Debt Securities [Member] | Minimum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Treasury Yield	212.00%	184.00%
US States and Political Subdivisions Debt Securities [Member] | Maximum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Treasury Yield	212.00%	184.00%
US States and Political Subdivisions Debt Securities [Member] | Weighted Average [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Treasury Yield	212.00%	184.00%
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Measurements, Valuation Techniques	Discounted cash flows	Discounted cash flows
Fair Value Measurements, Significant Assumptions	Spread	Spread
Fair Value Measurements, Sensitivity Analysis, Description	Decrease	Decrease
Corporate Debt Securities [Member] | Minimum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Counterparty Credit Risk	123.00%	119.00%
Corporate Debt Securities [Member] | Maximum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Counterparty Credit Risk	765.00%	5594.00%
Corporate Debt Securities [Member] | Weighted Average [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Counterparty Credit Risk	279.00%	344.00%
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Measurements, Valuation Techniques	Discounted cash flows	Discounted cash flows
Fair Value Measurements, Significant Assumptions	Spread (encompasses prepayment, default risk and loss severity)	Spread (encompasses prepayment, default risk and loss severity)
Fair Value Measurements, Sensitivity Analysis, Description	Decrease	Decrease
Commercial Mortgage Backed Securities [Member] | Minimum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Counterparty Credit Risk	46.00%	99.00%
Commercial Mortgage Backed Securities [Member] | Maximum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Counterparty Credit Risk	2475.00%	3000.00%
Commercial Mortgage Backed Securities [Member] | Weighted Average [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Counterparty Credit Risk	284.00%	527.00%
Residential Mortgage Backed Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities, Debt Securities	3,918	4,647
Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities, Debt Securities	1,281	1,272
US States and Political Subdivisions Debt Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities, Debt Securities	12,871	12,173
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities, Debt Securities	66	69
Corporate Debt Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities, Debt Securities	27,359	28,490
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities, Debt Securities	1,040	1,274
Commercial Mortgage Backed Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities, Debt Securities	4,415	4,446
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities, Debt Securities	284	663
Fair Value, Measurements, Recurring [Member] | Limited Partnerships and Other Alternative Investments [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Measurements, Valuation Processes, Description		The predominant valuation method uses a NAV calculated on a monthly basis and represents funds where the Company does not have the ability to redeem the investment in the near-term at that NAV, including an assessment of the investee's liquidity.
Fair Value, Measurements, Recurring [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities, Debt Securities	1,281	1,272
Fair Value, Measurements, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member] | Non-Broker Priced [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities, Debt Securities	32	29
Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Non-Broker Priced [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities, Debt Securities	568	665
Fair Value, Measurements, Recurring [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities, Debt Securities	284	663
Spread [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	Spread	Spread
Fair Value Measurements, Sensitivity Analysis, Description	Decrease	Decrease
Prepayment Rate [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	Constant prepayment rate	Constant prepayment rate
Fair Value Measurements, Sensitivity Analysis, Description	Decrease [4]	Decrease [4]
Probability of Default [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	Constant default rate	Constant default rate
Fair Value Measurements, Sensitivity Analysis, Description	Decrease	Decrease
Loss Severity [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	Loss severity	Loss severity
Fair Value Measurements, Sensitivity Analysis, Description	Decrease	Decrease
Living Benefits Required to be Fair Valued and the GMWB Reinsurance Derivative [Member] | Withdrawal Utilization [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Measurements, Sensitivity Analysis, Description	Increase
Living Benefits Required to be Fair Valued and the GMWB Reinsurance Derivative [Member] | Withdrawal Utilization [Member] | Minimum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Unobservable Input Range	20.00%
Living Benefits Required to be Fair Valued and the GMWB Reinsurance Derivative [Member] | Withdrawal Utilization [Member] | Maximum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Unobservable Input Range	100.00%
Living Benefits Required to be Fair Valued and the GMWB Reinsurance Derivative [Member] | Withdrawal Rates [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Measurements, Sensitivity Analysis, Description	Increase
Living Benefits Required to be Fair Valued and the GMWB Reinsurance Derivative [Member] | Withdrawal Rates [Member] | Minimum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Unobservable Input Range	0.00%
Living Benefits Required to be Fair Valued and the GMWB Reinsurance Derivative [Member] | Withdrawal Rates [Member] | Maximum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Unobservable Input Range	8.00%
Living Benefits Required to be Fair Valued and the GMWB Reinsurance Derivative [Member] | Lapse Rates [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Measurements, Sensitivity Analysis, Description	Decrease
Living Benefits Required to be Fair Valued and the GMWB Reinsurance Derivative [Member] | Lapse Rates [Member] | Minimum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Unobservable Input Range	0.00%
Living Benefits Required to be Fair Valued and the GMWB Reinsurance Derivative [Member] | Lapse Rates [Member] | Maximum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Unobservable Input Range	75.00%
Living Benefits Required to be Fair Valued and the GMWB Reinsurance Derivative [Member] | Reset Elections [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Measurements, Sensitivity Analysis, Description	Increase
Living Benefits Required to be Fair Valued and the GMWB Reinsurance Derivative [Member] | Reset Elections [Member] | Minimum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Unobservable Input Range	20.00%
Living Benefits Required to be Fair Valued and the GMWB Reinsurance Derivative [Member] | Reset Elections [Member] | Maximum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Unobservable Input Range	75.00%
Living Benefits Required to be Fair Valued and the GMWB Reinsurance Derivative [Member] | Equity Volatility [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Measurements, Sensitivity Analysis, Description	Increase
Living Benefits Required to be Fair Valued and the GMWB Reinsurance Derivative [Member] | Equity Volatility [Member] | Minimum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Unobservable Input Range	10.00%
Living Benefits Required to be Fair Valued and the GMWB Reinsurance Derivative [Member] | Equity Volatility [Member] | Maximum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Unobservable Input Range	40.00%
Interest Rate Contract [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	(29)	(24)
Fair Value Measurements, Valuation Techniques	Discounted cash flows	Discounted cash flows
Fair Value Measurements, Significant Assumptions	Swap curve beyond 30 years	Swap curve beyond 30 years
Fair Value Measurements, Sensitivity Analysis, Description	Decrease	Increase
Interest Rate Contract [Member] | Interest Rate Swap [Member] | Minimum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Measurements, Unobservable Swap Curve	3.00%	4.00%
Interest Rate Contract [Member] | Interest Rate Swap [Member] | Maximum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Measurements, Unobservable Swap Curve	3.00%	4.00%
US GMWB Hedging Instruments [Member] | Equity Option [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	46	72
Fair Value Measurements, Valuation Techniques	Option model	Option model
Fair Value Measurements, Significant Assumptions	Equity volatility	Equity volatility
Fair Value Measurements, Sensitivity Analysis, Description	Increase	Increase
US GMWB Hedging Instruments [Member] | Equity Option [Member] | Minimum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Assumptions, Expected Volatility Rate	22.00%	21.00%
US GMWB Hedging Instruments [Member] | Equity Option [Member] | Maximum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Assumptions, Expected Volatility Rate	34.00%	29.00%
US GMWB Hedging Instruments [Member] | Customized Swaps [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	124	74
Fair Value Measurements, Valuation Techniques	Discounted cash flows	Discounted cash flows
Fair Value Measurements, Significant Assumptions	Equity volatility	Equity volatility
Fair Value Measurements, Sensitivity Analysis, Description	Increase	Increase
US GMWB Hedging Instruments [Member] | Customized Swaps [Member] | Minimum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Assumptions, Expected Volatility Rate	10.00%	10.00%
US GMWB Hedging Instruments [Member] | Customized Swaps [Member] | Maximum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Assumptions, Expected Volatility Rate	40.00%	50.00%
US Macro Hedge Program [Member] | Equity Option [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	141	139
Fair Value Measurements, Valuation Techniques	Option model	Option model
Fair Value Measurements, Significant Assumptions	Equity volatility	Equity volatility
Fair Value Measurements, Sensitivity Analysis, Description	Increase	Increase
US Macro Hedge Program [Member] | Equity Option [Member] | Minimum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Assumptions, Expected Volatility Rate	27.00%	24.00%
US Macro Hedge Program [Member] | Equity Option [Member] | Maximum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Assumptions, Expected Volatility Rate	28.00%	31.00%
International Program Hedging Instruments [Member] | Equity Option [Member] | Non-Broker Priced [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net		(35)
Fair Value Measurements, Valuation Techniques		Option model
Fair Value Measurements, Significant Assumptions		Equity volatility
Fair Value Measurements, Sensitivity Analysis, Description		Increase
International Program Hedging Instruments [Member] | Equity Option [Member] | Minimum [Member] | Non-Broker Priced [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Assumptions, Expected Volatility Rate		24.00%
International Program Hedging Instruments [Member] | Equity Option [Member] | Maximum [Member] | Non-Broker Priced [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Assumptions, Expected Volatility Rate		37.00%
Long [Member] | Interest Rate Swaption [Member] | Minimum [Member] | Non-Broker Priced [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Assumptions, Expected Volatility Rate		1.00%
Long [Member] | Interest Rate Swaption [Member] | Maximum [Member] | Non-Broker Priced [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Assumptions, Expected Volatility Rate		1.00%
Long [Member] | Interest Rate Contract [Member] | Interest Rate Swaption [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	22	42
Fair Value Measurements, Valuation Techniques	Option model	Option model
Fair Value Measurements, Significant Assumptions	Interest rate volatility	Interest rate volatility
Fair Value Measurements, Sensitivity Analysis, Description	Increase	Increase
Long [Member] | Interest Rate Contract [Member] | Interest Rate Swaption [Member] | Minimum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Assumptions, Expected Volatility Rate	1.00%	1.00%
Long [Member] | Interest Rate Contract [Member] | Interest Rate Swaption [Member] | Maximum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Assumptions, Expected Volatility Rate	1.00%	1.00%
Long [Member] | International Program Hedging Instruments [Member] | Interest Rate Swaption [Member] | Non-Broker Priced [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net		50
Fair Value Measurements, Valuation Techniques		Option model
Fair Value Measurements, Significant Assumptions		Interest rate volatility
Fair Value Measurements, Sensitivity Analysis, Description		Increase
Short [Member] | Interest Rate Swaption [Member] | Minimum [Member] | Non-Broker Priced [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Assumptions, Expected Volatility Rate		0.00%
Short [Member] | Interest Rate Swaption [Member] | Maximum [Member] | Non-Broker Priced [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Assumptions, Expected Volatility Rate		1.00%
Short [Member] | International Program Hedging Instruments [Member] | Interest Rate Swaption [Member] | Non-Broker Priced [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net		(13)
Fair Value Measurements, Valuation Techniques		Option model
Fair Value Measurements, Significant Assumptions		Interest rate volatility
Fair Value Measurements, Sensitivity Analysis, Description		Decrease