Common Equity - Stock Options (Details) - Stock options - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Options Activity
Outstanding, shares, beginning balance	2,916,902	3,015,751
Granted, shares		294,990	257,780	437,269
Exercised, shares		(380,412)
Forfeited, shares		(10,286)
Expired, shares		(3,141)
Outstanding, shares, ending balance		2,916,902	3,015,751
Options - Weighted Average Exercise Price
Outstanding, Weighted-Average Exercise Price, Beginning	$ 82.32	$ 79.57
Granted, Weighted-Average Exercise Price		84.92
Exercised, Weighted-Average Exercise Price		62.20
Forfeited, Weighted-Average Exercise Price		91.82
Expired, Weighted Average Exercise Price		91.34
Outstanding, Weighted-Average Exercise Price, Ending		$ 82.32	$ 79.57
Options - Additional Disclosures
Outstanding, Weighted-Average Remaining Contractual Life (Years)		5 years 4 months 24 days
Outstanding, Aggregate Intrinsic Value		$ 35.0
Exercisable, shares		2,182,660
Exercisable, Weighted-Average Exercise Price (in dollars per share)		$ 79.16
Exercisable, Weighted-Average Remaining Contractual Life (Years)		4 years 7 months 6 days
Exercisable, Aggregate Intrinsic Value		$ 32.7
Intrinsic value of options exercised		11.2	$ 5.2	$ 29.2
Tax benefit from option exercises		3.1	$ 1.4	$ 8.0
Compensation cost not yet recognized		$ 1.4
Weighted-average period over which unrecognized compensation cost is expected to be recognized		1 year 7 months 6 days
Estimated weighted-average fair value per stock option (in dollars per share)		$ 16.19	$ 19.58	$ 14.71
Subsequent event
Options Activity
Granted, shares	231,024
Options - Weighted Average Exercise Price
Granted, Weighted-Average Exercise Price	$ 94.55
Options - Additional Disclosures
Estimated weighted-average fair value per stock option (in dollars per share)	$ 18.23