Investments - Payables for Collateral on Investments (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2026	Dec. 31, 2025
Carrying Value
Collateral payable for derivative investments	$ 6,373	$ 7,808
Securities pledged under securities lending agreements	183	145
Investments pledged for FHLBI	0	0
Total payables for collateral on investments	6,556	7,953
Fair Value
Collateral payable for derivative investments	6,373	7,808
Securities pledged under securities lending agreements	177	139
Investments pledged for FHLBI	0	0
Total payables for collateral on investments	$ 6,550	$ 7,947
Percentage of the fair value of domestic securities obtained as collateral under securities lending agreements.	102.00%	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%

Carrying Value Of Payables For Collateral On Investments [Abstract]

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- Definition

This item represents the percentage of the fair value of AFS securities obtained as collateral pledged.

+ References

No definition available.

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- Definition

This item represents the percentage of the fair value of Mortgage loans obtained as collateral pledged.

+ References

No definition available.

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- Definition

This item represents the percentage of the fair value of securities obtained as collateral under reverse repurchase agreements

+ References

No definition available.

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- Definition

This item represents the percentage of the fair value of domestic securities obtained as collateral under securities lending agreements

+ References

No definition available.

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- Definition

When entering into a derivative transaction, the amount of cash received as collateral from a counterparty.

+ References

No definition available.

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- Definition

The fair value of cash received as collateral from a counterparty.

+ References

No definition available.

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- Definition

Fair Value Of Related Investments Or Collateral [Abstract]

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No definition available.

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- Definition

The amount of cash received as security in return for loaning securities to Federal Home Loan Bank of Indianapolis.

+ References

No definition available.

+ Details

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- Definition

The fair value of investments loaned to Federal Home Loan Bank of Indianapolis as of the balance sheet date.

+ References

No definition available.

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- Definition

The fair value of investments loaned to another party under securities lending agreements as of the balance sheet date.

+ References

No definition available.

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- Definition

The total fair value of investments related to payables for collateral on investments as of the balance sheet date.

+ References

No definition available.

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- Definition

Amount of obligation to return cash received as collateral for security loaned to another party.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-04(11))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479170/946-210-S99-1

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- Definition

Amount, before effects of master netting arrangements, of financial assets loaned to entities in exchange for collateral. Includes liabilities not subject to a master netting arrangement and financial assets transferred other than securities that qualify as secured borrowings.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 860
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481395/860-30-55-4

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 860
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-Topic 860
-Publisher FASB
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