Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income [Roll Forward]
Balance	$ 6,170.5	$ 5,958.1	$ 10,107.4
OCI before reclassifications		338.1
Amounts reclassified from AOCI		(3.2)
Other comprehensive income (loss), net of tax	(167.5)	334.9	(66.5)
Balance	5,668.0	6,170.5	5,958.1
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income [Roll Forward]
Balance	253.1	(81.8)	(15.3)
OCI before reclassifications	(163.4)
Amounts reclassified from AOCI	(4.1)
Other comprehensive income (loss), net of tax	(167.5)	334.9	(66.5)
Balance	84.6	253.1	(81.8)
Fair value of derivative financial instruments, net of tax
Accumulated Other Comprehensive Income [Roll Forward]
Balance	(9.8)	(19.5)
OCI before reclassifications	(7.5)	7.1
Amounts reclassified from AOCI	1.8	2.6
Other comprehensive income (loss), net of tax	(5.7)	9.7
Balance	(15.5)	(9.8)	(19.5)
Foreign currency translation adjustments
Accumulated Other Comprehensive Income [Roll Forward]
Balance	260.6	(67.9)
OCI before reclassifications	(156.1)	328.5
Amounts reclassified from AOCI	0.0	0.0
Other comprehensive income (loss), net of tax	(156.1)	328.5
Balance	104.5	260.6	(67.9)
Fair value of investment securities, net of tax
Accumulated Other Comprehensive Income [Roll Forward]
Balance	1.0	15.1
OCI before reclassifications	0.0	(12.5)
Amounts reclassified from AOCI	0.0	(1.6)
Other comprehensive income (loss), net of tax	0.0	(14.1)
Balance	0.0	1.0	15.1
Post-retirement and pension liability adjustments, net of tax
Accumulated Other Comprehensive Income [Roll Forward]
Balance	1.3	(9.5)
OCI before reclassifications	0.2	15.0
Amounts reclassified from AOCI	(5.9)	(4.2)
Other comprehensive income (loss), net of tax	(5.7)	10.8
Balance	(4.4)	1.3	$ (9.5)
ASU 2016-01 \| Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income [Roll Forward]
Balance	252.1
Balance		252.1
ASU 2016-01 adoption impact		(1.0)
ASU 2016-01 \| Fair value of derivative financial instruments, net of tax
Accumulated Other Comprehensive Income [Roll Forward]
Balance	(9.8)
Balance		(9.8)
ASU 2016-01 adoption impact		0.0
ASU 2016-01 \| Foreign currency translation adjustments
Accumulated Other Comprehensive Income [Roll Forward]
Balance	260.6
Balance		260.6
ASU 2016-01 adoption impact		0.0
ASU 2016-01 \| Fair value of investment securities, net of tax
Accumulated Other Comprehensive Income [Roll Forward]
Balance	0.0
Balance		0.0
ASU 2016-01 adoption impact		(1.0)
ASU 2016-01 \| Post-retirement and pension liability adjustments, net of tax
Accumulated Other Comprehensive Income [Roll Forward]
Balance	$ 1.3
Balance		1.3
ASU 2016-01 adoption impact		$ 0.0

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