Investments and Derivative Instruments Level 4 Credit Derivatives (Details) - USD ($) $ in Millions		9 Months Ended	12 Months Ended
		Sep. 30, 2015	Dec. 31, 2014
Credit Derivatives [Line Items]
Derivative, Notional Amount		$ 63,704	$ 72,850
Basket Credit Default Swaps [Member]
Credit Derivatives Footnote [Abstract]
Amount of Standard Market Indices of Diversified Portfolios of Corporate Issuers		4,100	3,500
Credit Default Swap, Selling Protection [Member]
Credit Derivatives [Line Items]
Derivative, Notional Amount	[1],[2]	4,709	4,159
Credit Risk Derivatives, at Fair Value, Net		309	345
Credit Default Swap, Selling Protection [Member] | Credit Derivatives in Offsetting Positions [Member]
Credit Derivatives [Line Items]
Derivative, Notional Amount	[1],[2]	2,064	2,672
Credit Risk Derivatives, at Fair Value, Net		10	(5)
Credit Default Swap, Selling Protection [Member] | Debt Securities Payable [Member] | Standard & Poor's, BB Rating [Member] | External Credit Rating, Non Investment Grade [Member] | Single Name Credit Default Swaps [Member]
Credit Derivatives [Line Items]
Derivative, Notional Amount	[1]	25	29
Credit Risk Derivatives, at Fair Value, Net		$ 0	$ 0
Derivative, Average Remaining Maturity		1 year	2 years
Credit Default Swap, Selling Protection [Member] | Debt Securities Payable [Member] | Standard & Poor's, BB Rating [Member] | External Credit Rating, Non Investment Grade [Member] | Credit Derivatives in Offsetting Positions [Member] | Single Name Credit Default Swaps [Member]
Credit Derivatives [Line Items]
Derivative, Notional Amount	[1]	$ 25	$ 29
Credit Risk Derivatives, at Fair Value, Net		0	(1)
Credit Default Swap, Selling Protection [Member] | Debt Securities Payable [Member] | Standard & Poor's, BBB+ Rating [Member] | External Credit Rating, Investment Grade [Member] | Single Name Credit Default Swaps [Member]
Credit Derivatives [Line Items]
Derivative, Notional Amount	[1]	226	320
Credit Risk Derivatives, at Fair Value, Net		$ (1)	$ 5
Derivative, Average Remaining Maturity		2 years	2 years
Credit Default Swap, Selling Protection [Member] | Debt Securities Payable [Member] | Standard & Poor's, BBB+ Rating [Member] | External Credit Rating, Investment Grade [Member] | Basket Credit Default Swaps [Member]
Credit Derivatives [Line Items]
Derivative, Notional Amount	[1]	$ 2,985	$ 2,546
Credit Risk Derivatives, at Fair Value, Net		$ 19	$ 33
Derivative, Average Remaining Maturity		4 years	3 years
Credit Default Swap, Selling Protection [Member] | Debt Securities Payable [Member] | Standard & Poor's, BBB+ Rating [Member] | External Credit Rating, Investment Grade [Member] | Credit Derivatives in Offsetting Positions [Member] | Single Name Credit Default Swaps [Member]
Credit Derivatives [Line Items]
Derivative, Notional Amount	[1]	$ 226	$ 247
Credit Risk Derivatives, at Fair Value, Net		0	(5)
Credit Default Swap, Selling Protection [Member] | Debt Securities Payable [Member] | Standard & Poor's, BBB+ Rating [Member] | External Credit Rating, Investment Grade [Member] | Credit Derivatives in Offsetting Positions [Member] | Basket Credit Default Swaps [Member]
Credit Derivatives [Line Items]
Derivative, Notional Amount	[1]	1,414	1,973
Credit Risk Derivatives, at Fair Value, Net		(14)	(25)
Credit Default Swap, Selling Protection [Member] | Debt Securities Payable [Member] | Standard & Poor's, B Rating [Member] | External Credit Rating, Non Investment Grade [Member] | Basket Credit Default Swaps [Member]
Credit Derivatives [Line Items]
Derivative, Notional Amount	[1],[2],[3]		38
Credit Risk Derivatives, at Fair Value, Net	[2],[3]		$ (1)
Derivative, Average Remaining Maturity	[2],[3]		12 years
Credit Default Swap, Selling Protection [Member] | Debt Securities Payable [Member] | Standard & Poor's, B Rating [Member] | External Credit Rating, Non Investment Grade [Member] | Credit Derivatives in Offsetting Positions [Member] | Basket Credit Default Swaps [Member]
Credit Derivatives [Line Items]
Derivative, Notional Amount	[1],[2],[3]		$ 0
Credit Risk Derivatives, at Fair Value, Net	[2],[3]		0
Credit Default Swap, Selling Protection [Member] | Debt Securities Payable [Member] | Standard & Poor's, A+ Rating [Member] | External Credit Rating, Investment Grade [Member] | Embedded Derivative Financial Instruments [Member]
Credit Derivatives [Line Items]
Derivative, Notional Amount	[1]	350	350
Credit Risk Derivatives, at Fair Value, Net		$ 346	$ 342
Derivative, Average Remaining Maturity		2 years	2 years
Credit Default Swap, Selling Protection [Member] | Debt Securities Payable [Member] | Standard & Poor's, A+ Rating [Member] | External Credit Rating, Investment Grade [Member] | Credit Derivatives in Offsetting Positions [Member] | Embedded Derivative Financial Instruments [Member]
Credit Derivatives [Line Items]
Derivative, Notional Amount	[1]	$ 0	$ 0
Credit Risk Derivatives, at Fair Value, Net		0	0
Credit Default Swap, Selling Protection [Member] | Collateralized Mortgage Backed Securities [Member] | Standard & Poor's, AA+ Rating [Member] | External Credit Rating, Investment Grade [Member] | Basket Credit Default Swaps [Member]
Credit Derivatives [Line Items]
Derivative, Notional Amount	[1]	970	722
Credit Risk Derivatives, at Fair Value, Net		$ (32)	$ (12)
Derivative, Average Remaining Maturity		6 years	6 years
Credit Default Swap, Selling Protection [Member] | Collateralized Mortgage Backed Securities [Member] | Standard & Poor's, AA+ Rating [Member] | External Credit Rating, Investment Grade [Member] | Credit Derivatives in Offsetting Positions [Member] | Basket Credit Default Swaps [Member]
Credit Derivatives [Line Items]
Derivative, Notional Amount	[1]	$ 246	$ 269
Credit Risk Derivatives, at Fair Value, Net		1	3
Credit Default Swap, Selling Protection [Member] | Collateralized Mortgage Backed Securities [Member] | Standard & Poor's, CCC+ Rating [Member] | External Credit Rating, Non Investment Grade [Member] | Basket Credit Default Swaps [Member]
Credit Derivatives [Line Items]
Derivative, Notional Amount	[1]	153	154
Credit Risk Derivatives, at Fair Value, Net		$ (23)	$ (22)
Derivative, Average Remaining Maturity		1 year	2 years
Credit Default Swap, Selling Protection [Member] | Collateralized Mortgage Backed Securities [Member] | Standard & Poor's, CCC+ Rating [Member] | External Credit Rating, Non Investment Grade [Member] | Credit Derivatives in Offsetting Positions [Member] | Basket Credit Default Swaps [Member]
Credit Derivatives [Line Items]
Derivative, Notional Amount	[1]	$ 153	$ 154
Credit Risk Derivatives, at Fair Value, Net		$ 23	$ 23

[1] Notional amount is equal to the maximum potential future loss amount. These derivatives are governed by agreements, clearing house rules and applicable law which include collateral posting requirements. There is no additional specific collateral related to these contracts or recourse provisions included in the contracts to offset losses.

[2] [1]The average credit ratings are based on availability and the midpoint of the applicable ratings among Moody’s, S&P, Fitch, and Morningstar. If no rating is available from a rating agency, then an internally developed rating is used.

[3] Includes $4.1 billion and $3.5 billion as of September 30, 2015, and December 31, 2014, respectively, of standard market indices of diversified portfolios of corporate and CMBS issuers referenced through credit default swaps. These swaps are subsequently valued based upon the observable standard market index.