Recent Accounting Pronouncements Recent Accounting Pronouncements (Impact of Adoption - ASU 2014-09) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Item Effected [Line Items]
Cost of sales	$ 1,823.2	$ 1,809.0	$ 5,369.2	$ 5,180.3
Income tax provision (benefit)	15.5	91.3	(79.9)	124.2
Net earnings	176.7	88.3	301.3	451.7
Revenues	2,862.4	$ 2,987.1	8,355.2	$ 8,668.8
Prepaid expenses and other current assets	583.2		583.2			$ 784.6	$ 766.1
Deferred income tax liability	1,764.4		1,764.4			2,018.1	2,012.4
Income taxes payable	75.7		75.7				112.9
Retained earnings	5,965.8		5,965.8			5,664.8	5,644.5
Accumulated other comprehensive loss	(1,490.9)		(1,490.9)		$ (1,199.3)	$ (368.7)	(361.2)
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Item Effected [Line Items]
Cost of sales	1,876.4		5,475.5
Income tax provision (benefit)	15.0		(82.3)
Net earnings	175.6		296.2
Revenues	2,914.0		8,454.0
Prepaid expenses and other current assets	575.7		575.7
Income taxes payable	73.3		73.3
Retained earnings	5,960.7		5,960.7
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Item Effected [Line Items]
Cost of sales	(53.2)		(106.3)
Income tax provision (benefit)	0.5		2.4
Net earnings	1.1		5.1
Revenues	(51.6)		(98.8)
Prepaid expenses and other current assets	7.5		7.5
Income taxes payable	2.4		2.4
Retained earnings	$ 5.1		$ 5.1
Accounting Standards Update 2014-09 [Member]
Item Effected [Line Items]
Prepaid expenses and other current assets							18.5
Deferred income tax liability							5.7
Retained earnings							12.8
Accounting Standards Update 2016-01 [Member]
Item Effected [Line Items]
Retained earnings							10.0
Accumulated other comprehensive loss							(10.0)
Accounting Standards Update 2017-12 [Member]
Item Effected [Line Items]
Retained earnings							(2.5)
Accumulated other comprehensive loss							$ 2.5