Segment Information - Income Tax Expense (Benefit) by Segment (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Information: Income tax expense (benefit)
Income taxes (benefits)	$ 291.7	$ 68.7	$ 1,189.5
Operating Segments
Segment Information: Income tax expense (benefit)
Income taxes (benefits)	364.5	407.1	343.9
Reconciling items
Segment Information: Income tax expense (benefit)
Tax benefit related to net realized capital losses, as adjusted	(16.1)	(22.0)	(56.6)
Tax benefit from exited business (1)	17.6	(238.1)	956.4
Certain adjustments related to equity method investments and noncontrolling interest	(74.3)	(78.3)	(54.2)
Retirement and Income Solutions \| Operating Segments
Segment Information: Income tax expense (benefit)
Income taxes (benefits)	129.3	130.9	90.6
Principal Asset Management \| Operating Segments
Segment Information: Income tax expense (benefit)
Income taxes (benefits)	230.8	220.7	213.3
Benefits and Protection \| Operating Segments
Segment Information: Income tax expense (benefit)
Income taxes (benefits)	89.0	97.7	109.1
Corporate \| Operating Segments
Segment Information: Income tax expense (benefit)
Income taxes (benefits)	$ (84.6)	$ (42.2)	$ (69.1)

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to exited business.

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Adjustment for the income tax effect of the pre-tax net realized capital gains (losses), as adjusted.

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Tax expense (benefit) recognized during the period associated with certain adjustments related to equity method investments and noncontrolling interest.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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