Investments (Payables For Collateral On Investments) (Details) - USD ($) $ in Millions		6 Months Ended
		Jun. 30, 2016	Dec. 31, 2015
Carrying Value Of Payables For Collateral On Investments [Abstract]
Collateral payable held for derivative investments	[1]	$ 3,004	$ 1,387
Securities pledged under securities lending agreements	[2]	249	242
Securities pledged under reverse repurchase agreements	[3]	689	673
Investments pledged for Federal Home Loan Bank of Indianapolis ('FHLBI')	[4]	2,355	2,355
Total payables for collateral on investments		6,297	4,657
Fair Value Of Related Investments Or Collateral [Abstract]
Collateral payable held for derivative investments	[1]	3,004	1,387
Securities pledged under securities lending agreements	[2]	240	231
Securities pledged under reverse repurchase agreements	[3]	748	739
Investments pledged for Federal Home Loan Bank of Indianapolis('FHLBI')	[4]	3,767	3,391
Total payables for collateral on investments		$ 7,759	$ 5,748
Percentage of the fair value of domestic securities obtained as collateral under securities lending agreements.		102.00%
Percentage of the fair value of foreign securities obtained as collateral under securities lending agreements.		105.00%
Percentage of the fair value of securities obtained as collateral under reverse repurchase agreements.		95.00%
Minimum [Member]
Fair Value Of Related Investments Or Collateral [Abstract]
Percentage of the fair value of FHLBI securities obtained as collateral under securities pledged for FHLBI for AFS Securities		105.00%
Percentage of the fair value of FHLBI securities obtained as collateral under securities pledged for FHLBI for mortgage loan		155.00%
Maximum [Member]
Fair Value Of Related Investments Or Collateral [Abstract]
Percentage of the fair value of FHLBI securities obtained as collateral under securities pledged for FHLBI for AFS Securities		115.00%
Percentage of the fair value of FHLBI securities obtained as collateral under securities pledged for FHLBI for mortgage loan		175.00%

[1] We obtain collateral based upon contractual provisions with our counterparties. These agreements take into consideration the counterparties' credit rating as compared to ours, the fair value of the derivative investments and specified thresholds that if exceeded result in the receipt of cash that is typically invested in cash and invested cash. See Note 5 for additional information.

[2] Our pledged securities under securities lending agreements are included in fixed maturity AFS securities on our Consolidated Balance Sheets. We generally obtain collateral in an amount equal to 102% and 105% of the fair value of the domestic and foreign securities, respectively. We value collateral daily and obtain additional collateral when deemed appropriate. The cash received in our securities lending program is typically invested in cash and invested cash or fixed maturity AFS securities.

[3] Our pledged securities under repurchase agreements are included in fixed maturity AFS securities on our Consolidated Balance Sheets. We obtain collateral in an amount equal to 95% of the fair value of the securities, and our agreements with third parties contain contractual provisions to allow for additional collateral to be obtained when necessary. The cash received in our repurchase program is typically invested in fixed maturity AFS securities.

[4] Our pledged investments for FHLBI are included in fixed maturity AFS securities and mortgage loans on real estate on our Consolidated Balance Sheets. The collateral requirements are generally 105% to 115% of the fair value for fixed maturity AFS securities and 155% to 175% of the fair value of mortgage loans on real estate. The cash received in these transactions is primarily invested in cash and invested cash or fixed maturity AFS securities.