Stock-Based Compensation (Performance Share Units) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 28.4	$ 28.5	$ 30.1
Payout ratio for shares paid (as a percent)	100.00%
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award service period	3 years
Compensation expense	$ 12.8	$ 14.9	$ 15.2
Weighted-average fair value of grants, per share (in usd per share)	$ 558.78	$ 403.68	$ 0
Payout ratio for shares paid (as a percent)	200.00%	189.00%	131.00%
Distributed (in shares)	(42,200)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$ 289.77
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	18,100
Share-Based Compensation Arrangement By Share-based Payment Award, Equity Instruments Other Than Options, Adjustments In Period, Weighted Average Grant Date Fair Value	$ 245.27
Share-Based Compensation Arrangement By Share-based Payment Award, Equity Instruments Other Than Options, Adjustments In Period	30,400
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(7,100)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$ 387.59
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award service period	3 years
Compensation expense	$ 10.5	$ 9.4	$ 10.8
Weighted-average fair value of grants, per share (in usd per share)	$ 551.56	$ 404.91	$ 0
Distributed (in shares)	(40,600)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$ 243.07
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	24,100
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(8,900)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$ 388.26
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 5.1	$ 4.2	$ 4.1
Award expiration period	7 years
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(14,100)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$ 417.89