| CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions | Dec. 31, 2017 | Dec. 31, 2016 |
| Current assets: |
| Cash and cash equivalents | $ 418.6 | $ 560.9 |
| Accounts and other receivables: |
| Trade, less allowance for doubtful accounts of $17.2 and $10.7, respectively | 728.3 | 654.4 |
| Affiliate receivables | 5.5 | 15.1 |
| Other receivables, less allowance for doubtful accounts of $0.5 and $0.6, respectively | 168.2 | 135.8 |
| Inventories: |
| Inventories, less allowance for obsolete inventories of $8.1 and $3.3, respectively | 591.5 | 592.7 |
| Other current assets, net | 277.6 | 210.7 |
| Total current assets | 2,189.7 | 2,169.6 |
| Properties, less accumulated depreciation of $2,096.6 and $1,499.3, respectively | 4,673.7 | 4,507.4 |
| Goodwill | 8,405.5 | 8,250.1 |
| Other intangibles, less accumulated amortization of $662.3 and $404.0, respectively | 14,296.5 | 14,031.9 |
| Other assets | 681.5 | 382.5 |
| Total assets | 30,246.9 | 29,341.5 |
| Current liabilities: |
| Accounts payable and other current liabilities (includes affiliate payable amounts of $0.4 and $2.1, respectively) | 2,679.6 | 2,467.7 |
| Current portion of long-term debt and short-term borrowings | 714.8 | 684.8 |
| Discontinued operations | 4.9 | 5 |
| Total current liabilities | 3,399.3 | 3,157.5 |
| Long-term debt | 10,598.7 | 11,387.7 |
| Pension and postretirement benefits | 848.5 | 1,196 |
| Deferred tax liabilities | 1,648.6 | 1,699 |
| Other liabilities | 304.4 | 267 |
| Discontinued operations | 12.4 | 12.6 |
| Total liabilities | 16,811.9 | 17,719.8 |
| Commitments and contingencies | | |
| Molson Coors Brewing Company stockholders' equity |
| Preferred stock, $0.01 par value (authorized: 25.0 shares; none issued) | 0 | 0 |
| Paid-in capital | 6,688.5 | 6,635.3 |
| Retained earnings | 7,206.1 | 6,145.3 |
| Accumulated other comprehensive income (loss) | (860) | (1,571.8) |
| Class B common stock held in treasury at cost (9.5 shares and 9.5 shares, respectively) | (471.4) | (471.4) |
| Total Molson Coors Brewing Company stockholders' equity | 13,226.1 | 11,418.7 |
| Noncontrolling interests | 208.9 | 203 |
| Total equity | 13,435 | 11,621.7 |
| Total liabilities and equity | 30,246.9 | 29,341.5 |