Investments (Payables For Collateral On Investments) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Dec. 31, 2014
Carrying Value Of Payables For Collateral On Investments [Abstract]
Collateral payable held for derivative investments	2,051	[1]	$ 1,673	[1]
Securities pledged under securities lending agreements	204	[2]	204	[2]
Securities pledged under reverse repurchase agreements	616	[3]	607	[3]
Investments pledged for Federal Home Loan Bank of Indianapolis ('FHLBI')	2,175	[4]	1,925	[4]
Total payables for collateral on investments	5,046		4,409
Fair Value Of Related Investments Or Collateral [Abstract]
Collateral payable held for derivative investments	2,051	[1]	1,673	[1]
Securities pledged under securities lending agreements	193	[2]	196	[2]
Securities pledged under reverse repurchase agreements	672	[3]	666	[3]
Investments pledged for Federal Home Loan Bank of Indianapolis('FHLBI')	3,156	[4]	3,151	[4]
Total payables for collateral on investments	6,072		$ 5,686
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 FHLBI overcollateralization requirements for the assets that we pledge are generally 105% to 115% of the fair value for fixed maturity AFS securities and 155% to 175% of the unpaid principal balance for mortgage loans on real estate.  The cash received in these transactions is primarily invested in cash and invested cash or fixed maturity AFS securities.