Debt and Credit Agreements Schedule of Long-term Debt Instruments (Tables)

12 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Schedule of Long-term Debt Instruments [Table Text Block]

A summary of the carrying amounts and fair values of our long-term debt is listed below.

	Effective Interest Rate		December 31,
			2017				2016
			Book Value		Fair Value 1		Book Value		Fair Value 1
2.25% Senior Notes due 2017	2.30	%	$	0.0	$	0.0	$	299.4	$	301.4
4.00% Senior Notes due 2022 (less unamortized discount and issuance costs of $1.3 and $1.1, respectively)	4.13	%	247.6		259.0		247.0		258.4
3.75% Senior Notes due 2023 (less unamortized discount and issuance costs of $0.8 and $2.1, respectively)	4.32	%	497.1		513.2		496.6		503.3
4.20% Senior Notes due 2024 (less unamortized discount and issuance costs of $0.7 and $2.6, respectively)	4.24	%	496.7		524.2		496.2		511.6
Other notes payable and capitalized leases			46.2		46.2		65.4		65.4
Total long-term debt			1,287.6				1,604.6
Less: current portion			2.0				323.9
Long-term debt, excluding current portion			$	1,285.6			$	1,280.7

1 See Note 10 for information on the fair value measurement of our long-term debt.