Comprehensive Earnings (Accumulated Other Comprehensive Loss) (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	Mar. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision (benefit)	$ 15.5	$ 91.3	$ (79.9)	$ 124.2
Net unrealized gain on marketable securities, net of tax	0.0		0.0		$ 0.0		$ 10.1
Net unrecognized losses and prior service cost related to defined benefit plans, net of tax	(0.5)		(0.5)		4.3		6.0
Foreign currency translation adjustment	(1,231.4)		(1,231.4)		(960.6)		(133.8)
Accumulated other comprehensive loss	(1,490.9)		(1,490.9)		(1,199.3)	$ (368.7)	(361.2)
Other comprehensive (loss) earnings, before tax	(310.7)	338.6	(1,173.4)	1,663.8
Net unrealized (loss) gain on marketable securities	0.0	(8.9)	(0.1)	3.5
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	6.8	(1.1)	8.3	(2.4)
Sales Revenue, Goods, Net	2,827.3	2,956.3	8,233.2	8,570.2
Interest expense	136.2	131.8	407.1	406.3
Cash Flow Hedging
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net unrecognized gain (loss) on derivatives	(51.9)	(4.5)	(146.1)	29.2
Net Investment Hedging
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulate Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Net Investment Hedges, Effect Net of Taxx	(162.1)		(162.1)		(180.0)		(239.8)
Net unrecognized gain (loss) on derivatives	18.8	(72.1)	78.7	(203.2)
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision (benefit)		(5.8)		11.3
Accumulated other comprehensive loss		(611.2)		(611.2)				$ (955.6)	$ (2,263.7)
Other comprehensive earnings (loss) before reclassifications, before tax	(311.9)	338.4	(1,171.4)	1,653.8
Gains and Losses on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision (benefit)		(2.8)		9.4
Net unrecognized losses on derivatives in cash flow hedging relationships, net of tax		(18.8)		(18.8)				(17.1)	(38.6)
Other comprehensive earnings (loss) before reclassifications, before tax		(4.4)		19.9
Gains and Losses on Derivatives | Cash Flow Hedging
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision (benefit)	(18.0)		(50.4)
Cumulative Effect of New Accounting Principle in Period of Adoption	2.5		2.5
Net unrecognized losses on derivatives in cash flow hedging relationships, net of tax	(96.9)		(96.9)		$ (63.0)		$ (3.7)
Other comprehensive earnings (loss) before reclassifications, before tax	(52.9)		(143.7)
Gains and Losses on Derivatives | Net Investment Hedging
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision (benefit)	0.9	0.0	1.0	0.0
Cumulative Effect of New Accounting Principle in Period of Adoption	0.0		0.0
Net unrecognized losses on derivatives in cash flow hedging relationships, net of tax		(204.6)		(204.6)				(132.5)	(1.4)
Other comprehensive earnings (loss) before reclassifications, before tax		(72.1)		(203.2)
Gains and Losses on Marketable Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision (benefit)		(3.2)		1.4
Net unrealized gain on marketable securities, net of tax		16.6		16.6				22.3	14.5
Other comprehensive earnings (loss) before reclassifications, before tax		(8.9)		3.5
Defined Benefit Plan Items
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision (benefit)		0.2		(0.5)
Net unrecognized losses and prior service cost related to defined benefit plans, net of tax		1.4		1.4				(0.5)	(0.5)
Other comprehensive earnings (loss) before reclassifications, before tax	(7.0)	0.8	(8.7)	1.7
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision (benefit)		0.0		0.0
Foreign currency translation adjustment		(405.8)		(405.8)				$ (828.8)	$ (2,237.7)
Other comprehensive earnings (loss) before reclassifications, before tax	(270.8)		(1,097.6)
Reclassification out of Accumulated Other Comprehensive Earnings | AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision (benefit)	(19.1)		(51.2)
Cumulative Effect of New Accounting Principle in Period of Adoption	(7.5)		(7.5)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	(0.1)	0.1	(0.3)	(0.2)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax	(0.1)	0.2	(0.1)	(0.5)
Reclassification out of Accumulated Other Comprehensive Earnings | Gains and Losses on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net unrecognized gain (loss) on derivatives		(4.5)		29.2
Reclassification out of Accumulated Other Comprehensive Earnings | Gains and Losses on Marketable Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision (benefit)	0.0		0.0
Cumulative Effect of New Accounting Principle in Period of Adoption	(10.0)		(10.0)
Net unrealized (loss) gain on marketable securities		(8.9)		3.5
Reclassification out of Accumulated Other Comprehensive Earnings | Defined Benefit Plan Items
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision (benefit)	(2.0)		(1.8)
Cumulative Effect of New Accounting Principle in Period of Adoption	0.0		0.0
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax		1.1		(2.4)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax		0.1		0.2
Reclassification out of Accumulated Other Comprehensive Earnings | Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision (benefit)	0.0		0.0
Cumulative Effect of New Accounting Principle in Period of Adoption	0.0		0.0
Other comprehensive (loss) earnings, before tax		423.0		1,831.9
Mylan N.V.
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision (benefit)	(8.0)	2.4	(23.3)	1.4
Other comprehensive (loss) earnings, before tax	(310.7)	338.6	(1,173.4)	1,663.8
Net unrealized (loss) gain on marketable securities		(8.9)	(0.1)	3.5
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	6.8	(1.1)	8.3	(2.4)
Sales Revenue, Goods, Net	0.0	0.0	0.0	0.0
Interest expense	84.0	93.3	266.1	285.6
Mylan N.V. | Cash Flow Hedging
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net unrecognized gain (loss) on derivatives	(51.9)	(4.5)	(146.1)	29.2
Mylan N.V. | Net Investment Hedging
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net unrecognized gain (loss) on derivatives	18.8	(72.1)	78.7	(203.2)
Foreign currency forward contracts | Gains and Losses on Derivatives | Cash Flow Hedging
Accumulated Other Comprehensive Income (Loss) [Line Items]
Sales Revenue, Goods, Net	(0.9)		(8.1)
Foreign currency forward contracts | Reclassification out of Accumulated Other Comprehensive Earnings | AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Sales Revenue, Goods, Net	(0.9)	(2.0)	(8.1)	3.8
Foreign currency forward contracts | Reclassification out of Accumulated Other Comprehensive Earnings | Gains and Losses on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Sales Revenue, Goods, Net	(0.9)	(2.0)	(8.1)	3.8
Interest rate swaps | Gains and Losses on Derivatives | Cash Flow Hedging
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest expense	1.9		5.7
Interest rate swaps | Reclassification out of Accumulated Other Comprehensive Earnings | AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest expense	1.9	1.9	5.7	5.5
Interest rate swaps | Reclassification out of Accumulated Other Comprehensive Earnings | Gains and Losses on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest expense	1.9	1.9	5.7	5.5
Pension and other postretirement benefits
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	(0.1)	(0.1)	(0.3)	(0.2)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	(0.1)		(0.1)
Pension and other postretirement benefits | Reclassification out of Accumulated Other Comprehensive Earnings | Defined Benefit Plan Items
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	$ (0.1)		$ (0.3)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement		$ (0.2)		$ (0.5)