INCOME TAXES (Details 3) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of the Company's changes in gross uncertain tax positions
Gross reserve for uncertain tax positions related to foreign and domestic matters, including penalties and interest	$ 127.3us-gaap_UnrecognizedTaxBenefits	$ 102.6us-gaap_UnrecognizedTaxBenefits	$ 64.7us-gaap_UnrecognizedTaxBenefits	$ 29.7us-gaap_UnrecognizedTaxBenefits
Increases based on current year tax positions	26.6	23.8	17.8
Decreases based on current year tax positions	0	0	0
Increases based on prior year tax positions	10.4	18.9	21.4
Decreases based on prior year tax positions	(1.6)	0	0
Settlements	0	0	0
Lapse of statute of limitations	(9.9)mjn_LapseOfStatuteOfLimitations	(3.8)mjn_LapseOfStatuteOfLimitations	(5.2)mjn_LapseOfStatuteOfLimitations
Cumulative translation adjustment	(0.8)	(1.0)	1.0
Unrecognized Tax Benefits reversing within 12 months	5
Amounts of uncertain tax positions that, if recognized, would impact effective tax rate	69.8	48.6	18.9
Interest and penalties related to uncertain tax positions, included in other liabilities	19.5	14.8
Amount of interest and penalties included as a component of provision for income taxes	$ 3.7	$ 3.0	$ 5.0

Lapse of statute of limitations

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The amount of increase (decrease) in unrecognized tax benefits resulting from cumulative translation adjustment.

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Unrecognized Tax Benefits reversing within 12 months

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Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns.

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-Name Accounting Standards Codification

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Amount of decrease in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

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Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

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Amount of expense for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

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Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

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