Comprehensive Earnings (Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision	$ 27.7	$ 34.7	$ 32.9	$ 39.8
Net unrealized gain on marketable securities, net of tax	22.3		22.3			$ 14.5
Net unrecognized losses and prior service cost related to defined benefit plans, net of tax	0.5		0.5			(0.5)
Net unrecognized losses on derivatives in net investment hedging relationships, net of tax		3.4		(45.7)
Foreign currency translation adjustment	(828.8)		(828.8)			(2,237.7)
Accumulated other comprehensive loss	(955.6)		(955.6)			(2,263.7)
Cash Flow Hedging
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net unrecognized losses on derivatives in net investment hedging relationships, net of tax	1.3		33.7	(45.7)
Net Investment Hedging
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net unrecognized losses on derivatives in net investment hedging relationships, net of tax	(121.2)	0.0	(131.1)	0.0
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision				(13.2)
Accumulated other comprehensive loss	(955.6)	(1,431.3)	(955.6)	(1,431.3)	$ (1,813.0)	(2,263.7)	$ (1,290.5)	$ (1,764.3)
Gains and Losses on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision				(17.1)
Net unrecognized losses on derivatives in cash flow hedging relationships, net of tax		(46.7)		(46.7)			$ (48.9)	$ (18.1)
Gains and Losses on Derivatives | Cash Flow Hedging
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision	1.1		12.2
Net unrecognized losses on derivatives in cash flow hedging relationships, net of tax	(17.1)		(17.1)		(17.3)	(38.6)
Gains and Losses on Derivatives | Net Investment Hedging
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision	0.0		0.0
Net unrecognized losses on derivatives in cash flow hedging relationships, net of tax	(132.5)		(132.5)		$ (11.3)	$ (1.4)
Net unrecognized losses on derivatives in net investment hedging relationships, net of tax	(132.5)			(1.4)
Reclassification out of Accumulated Other Comprehensive Earnings | AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision	$ 3.1	3.6	$ 17.1
Reclassification out of Accumulated Other Comprehensive Earnings | Gains and Losses on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision		1.2
Net unrecognized losses on derivatives in net investment hedging relationships, net of tax		$ 3.4		$ (45.7)