Excess of issue price over par or stated value of the entity's capital stock and amounts received from other transactions involving the entity's stock or stockholders. Includes adjustments to additional paid in capital. Some examples of such adjustments include recording the issuance of debt with a beneficial conversion feature and certain tax consequences of equity instruments awarded to employees. Use this element for the aggregate amount of additional paid-in capital associated with common and preferred stock. For additional paid-in capital associated with only common stock, use the element additional paid in capital, common stock. For additional paid-in capital associated with only preferred stock, use the element additional paid in capital, preferred stock.

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Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of cash inflow (outflow) from financing activities, including discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit.

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New Accounting Pronouncements (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended			6 Months Ended	9 Months Ended
	Sep. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Jun. 30, 2016	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net Cash Provided by (Used in) Operating Activities		$ (88.3)		$ 282.4	$ 630.2	$ 479.0
Net Cash Provided by (Used in) Financing Activities		(2,458.5)		(2,338.6)	(9,120.1)	327.6
Income Tax Expense (Benefit)	$ 19.6	(16.7)	$ (27.3)	(37.9)	57.5	43.9
Net income (loss) attributable to MCBC	$ 202.5	$ 162.7	$ 16.6	$ 335.0	$ 537.5	$ 326.7
Basic net income (loss) attributable to Molson Coors Brewing Company per share	$ 0.94	$ 0.80	$ 0.09	$ 1.60	$ 2.55	$ 1.76
Diluted net income (loss) attributable to Molson Coors Brewing Company per share	$ 0.94	$ 0.80	$ 0.09	$ 1.59	$ 2.53	$ 1.75
Weighted average shares - diluted (in shares)	216.3	205.1	186.0	210.5	212.6	186.6
Paid-in capital	$ 6,565.6	$ 6,546.1		$ 6,552.7	$ 6,565.6		$ 4,000.4
Retained earnings	4,768.9	4,570.4		4,654.5	4,768.9		$ 4,496.0
Scenario, Previously Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net Cash Provided by (Used in) Operating Activities		(93.4)		264.4		$ 461.5
Net Cash Provided by (Used in) Financing Activities		(2,463.6)		(2,356.6)		$ 310.1
Income Tax Expense (Benefit)		(20.6)		(41.8)
Net income (loss) attributable to MCBC		$ 158.8		$ 331.1
Basic net income (loss) attributable to Molson Coors Brewing Company per share		$ 0.78		$ 1.58
Diluted net income (loss) attributable to Molson Coors Brewing Company per share		$ 0.78		$ 1.58
Weighted average shares - diluted (in shares)		204.8		210.2
Paid-in capital		$ 6,550.0		$ 6,556.6
Retained earnings		$ 4,566.5		$ 4,650.6
New Accounting Pronouncement, Early Adoption, Effect [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net Cash Provided by (Used in) Operating Activities					25.4
Net Cash Provided by (Used in) Financing Activities					25.4
Other Expense [Member] \| New Accounting Pronouncement, Early Adoption, Effect [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption	4.1				4.1
Additional Paid-in Capital [Member] \| New Accounting Pronouncement, Early Adoption, Effect [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption	$ 8.0				$ 8.0