Pension and Savings Plans - Changes in the Fair Value of Master Trust's Level 3 Investments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Level 3
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets at beginning of period	$ 0.3	$ 1.2	$ 4.1
Realized gains	0.1	0.9	1.6
Unrealized losses relating to investments still held at the reporting date	(68.8)	(0.6)	(2.1)
Purchases, sales and settlements, net	498.8	(1.2)	(2.4)
Fair value of plan assets at end of period	430.4	0.3	1.2
Pension Plan
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets at beginning of period	772.4	847.5
Fair value of plan assets at end of period	583.3	772.4	$ 847.5
Pension Plan | Level 3
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets at beginning of period	0.3
Fair value of plan assets at end of period	430.4	0.3
Pension Plan | Level 3 | Real estate interests
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets at beginning of period	0.3
Fair value of plan assets at end of period	$ 0.3	$ 0.3