Employee Benefits - Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	$ 2,624.3	$ 2,665.8	$ 2,628.0
Pension Plan | Level 1, 2, and 3
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	1,288.3	1,347.9
Pension Plan | Level 1, 2, and 3 | United States equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	168.4	179.3
Pension Plan | Level 1, 2, and 3 | International equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	158.2	174.0
Pension Plan | Level 1, 2, and 3 | United States bonds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	880.1	906.6
Pension Plan | Level 1, 2, and 3 | International bonds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	81.6	88.0
Pension Plan | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	326.6	353.3
Pension Plan | Level 1 | United States equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	168.4	179.3
Pension Plan | Level 1 | International equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	158.2	174.0
Pension Plan | Level 1 | United States bonds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Pension Plan | Level 1 | International bonds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Pension Plan | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	961.7	994.6
Pension Plan | Level 2 | United States equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Pension Plan | Level 2 | International equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Pension Plan | Level 2 | United States bonds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	880.1	906.6
Pension Plan | Level 2 | International bonds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	81.6	88.0
Pension Plan | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Pension Plan | Level 3 | United States equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Pension Plan | Level 3 | International equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Pension Plan | Level 3 | United States bonds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Pension Plan | Level 3 | International bonds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Pension Plan | Investments measured at net asset value per share | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	414.9	407.4
Pension Plan | Investments measured at net asset value per share | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	126.0	124.2
Pension Plan | Investments measured at net asset value per share | Other investments
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	795.1	786.3
OPEB Plan
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	850.0	829.6	$ 835.3
OPEB Plan | Level 1, 2, and 3
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	496.0	483.0
OPEB Plan | Level 1, 2, and 3 | United States equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	93.8	91.8
OPEB Plan | Level 1, 2, and 3 | International equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	86.4	84.6
OPEB Plan | Level 1, 2, and 3 | United States bonds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	304.6	294.7
OPEB Plan | Level 1, 2, and 3 | International bonds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	11.2	11.9
OPEB Plan | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	279.2	267.9
OPEB Plan | Level 1 | United States equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	93.8	91.8
OPEB Plan | Level 1 | International equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	86.4	84.6
OPEB Plan | Level 1 | United States bonds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	99.0	91.5
OPEB Plan | Level 1 | International bonds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
OPEB Plan | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	216.8	215.1
OPEB Plan | Level 2 | United States equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
OPEB Plan | Level 2 | International equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
OPEB Plan | Level 2 | United States bonds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	205.6	203.2
OPEB Plan | Level 2 | International bonds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	11.2	11.9
OPEB Plan | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
OPEB Plan | Level 3 | United States equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
OPEB Plan | Level 3 | International equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
OPEB Plan | Level 3 | United States bonds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
OPEB Plan | Level 3 | International bonds
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
OPEB Plan | Investments measured at net asset value per share | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	190.4	182.1
OPEB Plan | Investments measured at net asset value per share | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	51.8	47.7
OPEB Plan | Investments measured at net asset value per share | Other investments
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	$ 111.8	$ 116.8