Segment Information - Reconciliation of Segment Assets to Consolidated (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Segment Information
Total assets	$ 352,752.3	$ 341,376.5
Retirement and Income Solutions
Segment Information
Total assets	246,373.1	238,141.5
Principal Asset Management
Segment Information
Total assets	54,001.6	52,267.1
Benefits and Protection
Segment Information
Total assets	48,961.0	48,165.5
Corporate
Segment Information
Total assets	$ 3,416.6	$ 2,802.4