Employee Benefit Plans - Weighted average allocation of plan assets by asset category (Details)	Dec. 31, 2025
Weighted average allocation of plan assets by asset category
Allocation of plan assets (in percentage)	100.00%
U.K. and other international equities
Weighted average allocation of plan assets by asset category
Allocation of plan assets (in percentage)	33.60%
U.K. government and corporate bonds
Weighted average allocation of plan assets by asset category
Allocation of plan assets (in percentage)	3.90%
Diversified growth fund
Weighted average allocation of plan assets by asset category
Allocation of plan assets (in percentage)	21.40%
Liability driven investments
Weighted average allocation of plan assets by asset category
Allocation of plan assets (in percentage)	35.60%
Multi-asset credit fund
Weighted average allocation of plan assets by asset category
Allocation of plan assets (in percentage)	5.50%