Fair Value (Tables)

12 Months Ended

Dec. 31, 2020

Fair Value Disclosures [Abstract]

Recurring Fair Value Measures [Table Text Block]

	Fair Value as of December 31, 2020
Recurring Fair Value Measures	Level 1	Level 2	Level 3	Total
Millions
Assets:
Investments (a)
Available-for-sale – Equity Securities	$7.2	—	—	$7.2
Available-for-sale – Corporate and Governmental Debt Securities (b)	—	$10.4	—	10.4
Cash Equivalents	5.5	—	—	5.5
Total Fair Value of Assets	$12.7	$10.4	—	$23.1
Liabilities:
Deferred Compensation (c)	—	$21.0	—	$21.0
Total Fair Value of Liabilities	—	$21.0	—	$21.0
Total Net Fair Value of Assets (Liabilities)	$12.7	$(10.6)	—	$2.1

(a)Included in Other Non-Current Assets on the Consolidated Balance Sheet.

(b)As of December 31, 2020, the aggregate amount of available-for-sale corporate and governmental debt securities maturing in one year or less was $1.8 million, in one year to less than three years was $4.3 million, in three years to less than five years was $4.0 million and in five or more years was $0.3 million.

(c)Included in Other Non-Current Liabilities on the Consolidated Balance Sheet.

	Fair Value as of December 31, 2019
Recurring Fair Value Measures	Level 1	Level 2	Level 3	Total
Millions
Assets:
Investments (a)
Available-for-sale – Equity Securities	$11.1	—	—	$11.1
Available-for-sale – Corporate and Governmental Debt Securities	—	$9.7	—	9.7
Cash Equivalents	0.9	—	—	0.9
Total Fair Value of Assets	$12.0	$9.7	—	$21.7
Liabilities: (b)
Deferred Compensation	—	$21.2	—	$21.2
Total Fair Value of Liabilities	—	$21.2	—	$21.2
Total Net Fair Value of Assets (Liabilities)	$12.0	$(11.5)	—	$0.5

(a)Included in Other Non-Current Assets on the Consolidated Balance Sheet.

(b)Included in Other Non-Current Liabilities on the Consolidated Balance Sheet.

Financial Instruments [Table Text Block]

Financial Instruments	Carrying Amount	Fair Value
Millions
Short-Term and Long-Term Debt (a)
December 31, 2020	$1,806.4	$2,122.0
December 31, 2019	$1,622.6	$1,791.8

(a) Excludes unamortized debt issuance costs.