Debt and Credit Agreements Summary of New Debt Issuance (Tables)

12 Months Ended

Dec. 31, 2018

Debt Disclosure [Abstract]

Summary of New Debt Issuance [Table Text Block]

The issuance was comprised of the following four series of notes:

Senior Notes	Par Value		Discount at Issuance		Net Price at Issuance		Issuance Cost		Net Proceeds
3.50% Senior Notes due 2020	$	500.0	$	1.0	$	499.0	$	2.9	$	496.1
3.75% Senior Notes due 2021	500.0		0.3		499.7		3.2		496.5
4.65% Senior Notes due 2028	500.0		1.7		498.3		4.4		493.9
5.40% Senior Notes due 2048	500.0		2.8		497.2		5.6		491.6
Total	$	2,000.0	$	5.8	$	1,994.2	$	16.1	$	1,978.1