Separate Account Balances - Principal Asset Management - International Pension (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
Jun. 30, 2026	Dec. 31, 2025
Changes in separate account liabilities
Balance at beginning of period	$ 193,622.6
Balance at end of period	202,396.0	$ 193,622.6
Principal Asset Management \| International Pension \| Pension \| Latin America
Changes in separate account liabilities
Balance at beginning of period	41,450.5	32,802.2
Premiums and deposits	2,129.2	3,546.2
Policy charges	(10.3)	(17.7)
Surrenders, withdrawals and benefit payments	(2,261.1)	(3,962.7)
Investment performance	3,081.8	5,392.1
Other	(15.5)	2.7
Foreign currency translation adjustment	(1,050.8)	3,687.7
Balance at end of period	43,323.8	41,450.5
Cash surrender value	$ 43,323.8	$ 41,450.5

Amount increase (decrease) in separate account liability from foreign currency translation.

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Amount of decrease in separate account liability from contract redemption and withdrawal of funds and cash outflow to separate account policyholder from benefit payment.

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Amount of separate account liability payable to policyholder upon surrender of contract before maturity.

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Amount of increase (decrease) in separate account liability from performance of investment.

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Amount increase (decrease) in separate account liability from change, classified as other.

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Amount of decrease in separate account liability from policy charge.

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Amount of cash inflow to separate account liability from premium and deposit from cash received.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of liability for variable contract in which all or portion of contract holder's funds is allocated to specific separate account and supported by assets held in separate account.

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