Investments - Payables for Collateral on Investments (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2025	Dec. 31, 2024
Carrying Value
Collateral payable for derivative investments	$ 5,003	$ 7,213
Securities pledged under securities lending agreements	155	157
Securities pledged under repurchase agreements	418	0
Investments pledged for FHLBI	2,890	2,650
Total payables for collateral on investments	8,466	10,020
Fair Value
Collateral payable for derivative investments	5,003	7,213
Securities pledged under securities lending agreements	150	151
Securities pledged under repurchase agreements	435	0
Investments pledged for Federal Home Loan Bank of Indianapolis('FHLBI')	4,124	3,657
Total payables for collateral on investments	$ 9,712	$ 11,021
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%
Minimum
Fair Value
Percentage of the fair value of securities obtained as collateral under reverse repurchase agreements	80.00%
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
Fair Value
Percentage of the fair value of securities obtained as collateral under reverse repurchase agreements	95.00%
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%