Pension and Other Postretirement Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2023

Retirement Benefits [Abstract]

Components of Net Periodic Benefit Expense (Income) [Table Text Block]

	Pension		Other Postretirement
Components of Net Periodic Benefit Cost (Credit)	2023	2022	2023	2022
Millions
Quarter Ended June 30,
Service Cost	$1.6	$2.4	$0.5	$0.7
Non-Service Cost Components (a)
Interest Cost	10.1	6.8	1.5	1.1
Expected Return on Plan Assets	(11.0)	(10.3)	(2.8)	(2.4)
Amortization of Prior Service Credits	—	(0.1)	(1.7)	(1.9)
Amortization of Net Loss	1.5	2.6	(0.6)	0.1
Net Periodic Benefit Cost (Credit)	$2.2	$1.4	$(3.1)	$(2.4)
Six Months Ended June 30,
Service Cost	$3.2	$4.8	$1.1	$1.5
Non-Service Cost Components (a)
Interest Cost	20.2	13.5	3.0	2.2
Expected Return on Plan Assets	(21.9)	(20.7)	(5.6)	(4.8)
Amortization of Prior Service Credits	—	(0.1)	(3.5)	(3.8)
Amortization of Net Loss	2.9	5.8	(1.1)	0.2
Net Periodic Benefit Cost (Credit)	$4.4	$3.3	$(6.1)	$(4.7)

(a)These components of net periodic benefit cost (credit) are included in the line item “Other” under Other Income (Expense) on the Consolidated Statement of Income.