betfred sportsbook|Welcome_SEGMENT REPORTING SEGMENT

Betfred	12 Months Ended	11 Months Ended
Betfred	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2013	Jan. 26, 2015	Sep. 30, 2014	May 31, 2015	Jan. 22, 2015
Subsequent Event [Line Items]
Debt Instrument, Par Value	$ 4,144,800,000clf_DebtInstrumentParValue		$ 4,814,800,000clf_DebtInstrumentParValue
Estimated Capital Costs to Develop Bloom Lake Phase II	1,200,000,000
Elimination of Dividend [Member]
Subsequent Event [Line Items]
Elimination of Dividend				$ 0.15
Free Cash Flow Due to Quarterly Dividend Elimination				92,000,000
Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Debt Instrument, Par Value	1,125,000,000		1,750,000,000		1,250,000,000
Revolving Credit Facility [Member] \| Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount, Subsequent Event - Revolving Credit Facility Amendment						750,000,000	900,000,000
Permit Costs and Expenses in connection with Canadian Restructuring EBITDA Add back- Subsequent Event - Revolving Credit Facility Amendment		$ 75,000,000
betfred sportsbookLimit on Dividend per Share - Subsequent Event - Revolving Credit Facility Amendment		$ 0.01