Pension and Other Postretirement Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2021

Retirement Benefits [Abstract]

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

	Pension		Other Postretirement
Components of Net Periodic Benefit Cost (Credit)	2021	2020	2021	2020
Millions
Quarter Ended June 30,
Service Cost	$2.8	$2.7	$0.9	$0.9
Non-Service Cost Components (a)
Interest Cost	6.2	7.0	1.1	1.2
Expected Return on Plan Assets	(10.9)	(10.7)	(2.5)	(2.4)
Amortization of Prior Service Credits	(0.1)	(0.1)	(1.9)	(2.0)
Amortization of Net Loss	4.7	3.2	0.8	0.2
Net Periodic Benefit Cost (Credit)	$2.7	$2.1	$(1.6)	$(2.1)
Six Months Ended June 30,
Service Cost	$5.5	$5.3	$1.8	$1.7
Non-Service Cost Components (a)
Interest Cost	12.3	14.0	2.2	2.5
Expected Return on Plan Assets	(21.7)	(21.4)	(4.9)	(4.9)
Amortization of Prior Service Credits	(0.1)	(0.1)	(3.8)	(4.0)
Amortization of Net Loss	9.4	6.4	1.5	0.5
Net Periodic Benefit Cost (Credit)	$5.4	$4.2	$(3.2)	$(4.2)

(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.